Recent Journal Articles: Anatomy and Morphology -- Neurotransmitter.net

Recent Articles in Journal of Pineal Research

Furio AM, Brusco LI, Cardinali DP
Possible therapeutic value of melatonin in mild cognitive impairment: a retrospective study.
J Pineal Res. 2007 Nov;43(4):404-9.
Mild cognitive impairment (MCI) is an etiologically heterogeneous syndrome characterized by cognitive impairment preceding dementia. Approximately 12% of MCI patients convert to Alzheimer's disease (AD) or other dementia disorders every year. In the present report we retrospectively examined the initial and final neuropsychological assessment of 50 MCI outpatients, 25 of whom had received daily 3-9 mg of a fast-release melatonin preparation p.o. at bedtime for 9-18 months. Melatonin was given in addition to the standard medication prescribed by the attending psychiatrist. Patients treated with melatonin showed significantly better performance in Mini Mental State Examination and the cognitive subscale of the Alzheimer's Disease Assessment Scale. After application of a battery of neuropsychological tests including Mattis' test, Digit-symbol test, Trail A and B tasks and the Rey's verbal test, better performance was found in melatonin-treated patients, except for the Digit-symbol test score which remained unchanged. Abnormally high Beck Depression Inventory scores decreased in melatonin-treated patients, concomitantly with an improvement in wakefulness and sleep quality. The results suggest that melatonin can be a useful add-on drug for treating MCI in a clinical setting. [Abstract]

Jou MJ, Peng TI, Yu PZ, Jou SB, Reiter RJ, Chen JY, Wu HY, Chen CC, Hsu LF
Melatonin protects against common deletion of mitochondrial DNA-augmented mitochondrial oxidative stress and apoptosis.
J Pineal Res. 2007 Nov;43(4):389-403.
Defected mitochondrial respiratory chain (RC), in addition to causing a severe ATP deficiency, often augments reactive oxygen species (ROS) generation in mitochondria (mROS) which enhances pathological conditions and diseases. Previously, we demonstrated a potent endogenously RC defect-augmented mROS associated dose-dependently with a commonly seen large-scale deletion of 4977 base pairs of mitochondrial DNA (mtDNA), i.e. the common deletion (CD). As current treatments for CD-associated diseases are rather supplementary and ineffective, we investigated whether melatonin, a potential mitochondrial protector, provides beneficial protection for CD-augmented mitochondrial oxidative stress and apoptosis particularly upon the induction of a secondary oxidative stress. Detailed mechanistic investigations were performed by using laser scanning dual fluorescence imaging microscopy to provide precise spatial and temporal resolution of mitochondrial events at single cell level. We demonstrate, for the first time, that melatonin significantly prevents CD-augmented mROS formation under basal conditions as well as at early time-points upon secondary oxidative stress induced by H2O2 exposure. Thus, melatonin prevents mROS-mediated depolarization of mitochondrial membrane potential (DeltaPsim) and subsequent opening of the mitochondrial permeability transition pore (MPTP) and cytochrome c release. Moreover, melatonin prevents depletion of cardiolipin which appears to be crucial for postponing later MPTP opening, disruption of the mitochondrial membrane and apoptosis. Finally, the protection provided by melatonin is superior to those caused by the suppression of mitochondrial Ca2+ regulators including the mitochondrial Na+-Ca2) exchanger, the MPTP, and the mitochondrial Ca2+ uniporter and by antioxidants including vitamin E and mitochondria-targeted coenzyme Q, MitoQ. As RC defect-augmented endogenous mitochondrial oxidative stress is centrally involved in a variety of pathological conditions and diseases, melatonin thus may serve as a therapeutic drug to benefit many clinical conditions that involve malfunction of the mitochondria. [Abstract]

Hardeland R, Backhaus C, Fadavi A
Reactions of the NO redox forms NO+, *NO and HNO (protonated NO-) with the melatonin metabolite N1-acetyl-5-methoxykynuramine.
J Pineal Res. 2007 Nov;43(4):382-8.
The different NO redox forms, NO+, *NO and HNO (=protonated NO-), were compared for their capabilities of interacting with the melatonin metabolite N1-acetyl-5-methoxykynuramine (AMK), using NO+SbF6-, PAPA-NONOate and Angeli's salt as donors of the respective NO species. Particular attention was paid to stability and possible interconversions of the redox forms. *NO formation was followed by measuring the decolorization of 2-(trimethylammonio-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (TMA-PTIO), at different pH values, at which NO+ is, in aqueous solution, either highly unstable (pH 7.4) or relatively stable (pH 2.0). *NO donation by PAPA-NONOate, as indicated by TMA-PTIO decolorization, was similar at either pH and 3-acetamidomethyl-6-methoxycinnolinone (AMMC) was formed as the major product from AMK, at pH 7.4 more efficiently than at pH 2.0. At pH 2.0, TMA-PTIO decolorization by NO+SbF6- was much weaker than by PAPA-NONOate, but AMMC was produced at substantial rates, whereas neither TMA-PTIO decolorization nor AMMC formation was observed with the NO+ donor at pH 7.4. As NO+ is also stable in organic, especially aprotic solvents, NO+SbF6- was reacted with AMK in acetonitrile, ethanol, butanol, and ethyl acetate. In all these cases, AMMC was the only or major product. In ethyl acetate, N1-acetyl-5-methoxy-3-nitrokynuramine (AMNK) was also formed, presumably as a consequence of organic peroxides emerging in that solvent. Presence of tert-butylhydroperoxide in an ethanolic solution of NO+SbF6- and AMK also resulted in AMNK formation, in addition to AMMC and two red-fluoresecent, to date unknown products. However, hydrogen peroxide enhanced *NO-dependent AMMC production from AMK and also from N1-acetyl-N2-formyl-5-methoxykynuramine. HNO donation by Angeli's salt (Na2N2O3) also caused AMMC formation from AMK at pH 7.4, with a somewhat lower efficiency than PAPA-NONOate, but no AMNK nor any other product was detected. Therefore, all three NO congeners are, in principle, capable of nitrosating AMK and forming AMMC, but in biological material the reaction with NO+ is strongly limited by the extremely short life-time of this redox form. [Abstract]

Guha M, Maity P, Choubey V, Mitra K, Reiter RJ, Bandyopadhyay U
Melatonin inhibits free radical-mediated mitochondrial-dependent hepatocyte apoptosis and liver damage induced during malarial infection.
J Pineal Res. 2007 Nov;43(4):372-81.
We showed earlier that malarial infection significantly induces liver apoptosis mediated by oxidative stress mechanisms. Thus, a nontoxic antioxidant-antiapoptotic molecule may be beneficial for hepatoprotection. Melatonin remarkably prevents hepatocyte apoptosis in mice induced during malaria as indicated by caspase 3 and TUNEL assays as well as transmission electron microscopy (TEM) of the liver tissue. The mitochondrial apoptotic pathway, which plays a critical role in liver cell death during malarial infection, was almost completely suppressed by melatonin as it corrects both the overexpression of Bax and down-regulation of bcl-2 as revealed by semiquantitative RT-PCR. Fluorometric studies using JC-1 documented that melatonin also restores mitochondrial transmembrane potential (DeltaPsim) in malaria-infected mice liver. The antiapoptotic effect of melatonin is associated with its antioxidant role because melatonin protects liver from oxidative stress induced during malaria by scavenging the hydroxyl radicals, preventing the depletion of reduced glutathione, inhibiting lipid peroxidation and protein carbonyl formation. The effective antioxidant dose of melatonin to protect liver from oxidative stress during malaria is 20 times lower than that of known antioxidants, vitamin C and vitamin E. Apoptosis of hepatocytes during malarial infection is well correlated with dysfunction of the liver while melatonin offers hepatoprotective effects as indicated by different liver function tests. Thus, melatonin may well be effective in combating oxidative stress-induced apoptosis and liver damage during malaria infection. [Abstract]

Pontes GN, Cardoso EC, Carneiro-Sampaio MM, Markus RP
Pineal melatonin and the innate immune response: the TNF-alpha increase after cesarean section suppresses nocturnal melatonin production.
J Pineal Res. 2007 Nov;43(4):365-71.
The nocturnal surge of melatonin is the endocrine expression of the circadian system and is essential for organizing the timing of various endogenous processes. Previous works suggest that, in the beginning of a defense response, the increase in circulating tumor necrosis factor-alpha (TNF-alpha) leads to a transient block of nocturnal melatonin production and promotes a disruption of internal time organization. In the present paper, the concentration of melatonin and cytokines [TNF-alpha, interferon-gamma (IFN-gamma), interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12] in the colostrum (postdelivery day 3) and in the milk (postdelivery days 10, 15, 20 and 30) obtained at midday and midnight from mothers who gave birth by vaginal or cesarean section were compared. The nocturnal melatonin surge observed 3 days after vaginal delivery was absent after cesarean section. IL-12 presented no daily variation in either case, while daily variations in IFN-gamma, IL-10, IL-4 and IL-5 were observed after vaginal delivery and cesarean section. On the other hand, the increase in TNF-alpha after cesarean section resulted in suppression of the nocturnal melatonin surge. Daily variation of IL-2 was only observed after recovery of the nocturnal melatonin surge, 30 days after cesarean section. The present paper supports the hypothesis of a cross-talk between the pineal gland and the immune system, which could represent a putative immune-pineal axis. [Abstract]

Beraldo FH, Mikoshiba K, Garcia CR
Human malarial parasite, Plasmodium falciparum, displays capacitative calcium entry: 2-aminoethyl diphenylborinate blocks the signal transduction pathway of melatonin action on the P. falciparum cell cycle.
J Pineal Res. 2007 Nov;43(4):360-4.
The malarial parasite senses the environment to modulate its own cycle. Knowledge of the mechanisms for regulation signaling processes at the invasion, maturation, as well as division of Plasmodium falciparum before reinvasion would represent a major breakthrough and, therefore, might open new avenues for therapy. We have previously reported that melatonin modulates the circadian rhythm of malarial parasites through the activation of phospholipase C (PLC), production of InsP3, and induction of calcium release from intracellular stores. To further investigate the molecular mechanism of melatonin's action, we have used the InsP3 modulator 2-aminoethyl diphenylborinate (2-APB) given in a culture of P. falciparum parasites. Here we show that the melatonin acts on Plasmodium cell cycle through InsP3 signaling as 2-APB blocks melatonin's effect on calcium release. The function of the InsP3 signaling can be regarded as an important event for parasite invasion and maturation process, since addition of the PLC inhibitor, U73122 into Plasmodium-infected red blood cells impairs parasite invasion in vitro. By using 8BrcAMP, we also report here that Plasmodia displays a 'capacitative calcium entry' mechanism for amplification of calcium signals throughout the cytoplasm. [Abstract]

Carr R, Wasdell MB, Hamilton D, Weiss MD, Freeman RD, Tai J, Rietveld WJ, Jan JE
Long-term effectiveness outcome of melatonin therapy in children with treatment-resistant circadian rhythm sleep disorders.
J Pineal Res. 2007 Nov;43(4):351-9.
To date, there have been no prospective long-term studies of melatonin therapy in children. We report here data from a prospective follow-up study of 44 children with neurodevelopmental disabilities and treatment-resistant circadian rhythm sleep disorders (CRSD) who had participated in a placebo controlled, double blind cross-over trial of sustained-release melatonin. The follow-up study involved a structured telephone interview of caregivers every 3 months for upto 3.8 yr. The caregivers provided ratings of satisfaction, adverse effects, benefits, persistence with treatment and additional medications. Changes in melatonin dose were recorded. Open ended questions were included to capture caregivers' impressions and comments concerning melatonin therapy. Adverse reaction to melatonin therapy and development of tolerance were not evident. Better sleep was associated with reported improvement in health, behavior and learning. At the end of the study, the parental comments regarding the effectiveness of long-term melatonin therapy were highly positive. Parents whose children had sleep maintenance difficulties expressed a wish to have a commercially available controlled-release melatonin product which would promote sleep for 8-10 hr. Hypnotics for children with CRSD should be considered a second line of treatment for those who fail to respond to sleep hygiene and/or melatonin. [Abstract]

Kopczak A, Korth HG, de Groot H, Kirsch M
N-nitroso-melatonin releases nitric oxide in the presence of serotonin and its derivatives.
J Pineal Res. 2007 Nov;43(4):343-50.
A novel reaction was observed between 5-hydroxytryptophan derivatives like serotonin and N-nitroso-melatonin (NOMela). This reaction decreased the concentration of serotonin by about 50% and generated initially as detectable products nitric oxide and melatonin with stoichiometrical yields. The other expected product, a serotonin-derived radical, could not be detected by electron spin resonance (ESR) spectrometry, probably because the self-decay of phenoxyl type radicals proceed at the diffusion-controlled limit. From the facts that the decay rate of NOMela corresponded very well with the nitric oxide releasing rate and that nitrite was the only thermodynamically stable nitrogen oxide-containing product, it is concluded that the NOMela-serotonin reaction proceeded quantitatively. The observed reaction might be a possibility to counteract a pharmacologically abnormal high serotonin concentration in various diseases. [Abstract]

Gorfine T, Yeshurun Y, Zisapel N
Nap and melatonin-induced changes in hippocampal activation and their role in verbal memory consolidation.
J Pineal Res. 2007 Nov;43(4):336-42.
Overnight sleep contributes to memory consolidation; even a short nap improves memory performance. Such improvement has been linked to hippocampal activity during sleep. Melatonin has been shown to affect the human hippocampus and to induce 'sleep like' changes in brain activation. We therefore conducted and compared two functional magnetic resonance imaging studies: the first study assessed the effect of a 2-hr mid-day nap versus an equal amount of wakefulness on a verbal memory task (unrelated word pair association); the second assessed the effect of melatonin versus placebo (both conditions without nap) on a similar task. We report that following a nap relative to wakefulness, successful retrieval-related activation in the parahippocampus is decreased. A smaller decrease is seen in wakefulness with melatonin but not placebo. In parallel, an improvement in verbal memory recall was found after a nap compared with wakefulness but not with melatonin during wakefulness compared with placebo. Our findings demonstrate effects of melatonin that resemble those of sleep on verbal memory processing in the hippocampus thus suggesting that melatonin, like sleep, can initiate offline plastic changes underlying memory consolidation; they also suggest that concomitant rest without interferences is necessary for enhanced performance. [Abstract]

Migaud H, Davie A, Martinez Chavez CC, Al-Khamees S
Evidence for differential photic regulation of pineal melatonin synthesis in teleosts.
J Pineal Res. 2007 Nov;43(4):327-35.
The aim of this study was to compare the circadian control of melatonin production in teleosts. To do so, the effects of ophthalmectomy on circulating melatonin rhythms were studied along with ex vivo pineal culture in six different teleosts. Results strongly suggested that the circadian control of melatonin production could have dramatically changed with at least three different systems being present in teleosts when one considers the photic regulation of pineal melatonin production. First, salmonids presented a decentralized system in which the pineal gland responds directly to light independently of the eyes. Then, in seabass and cod both the eyes and the pineal gland are required to sustain full night-time melatonin production. Finally, a third type of circadian control of melatonin production is proposed in tilapia and catfish in which the pineal gland would not be light sensitive (or only slightly) and required the eyes to perceive light and inhibit melatonin synthesis. Further studies (anatomical, ultrastructural, retinal projections) are needed to confirm these results. Ex vivo experiments indirectly confirmed these results, as while the pineal gland responded normally to day-night rhythms in salmonids, seabass and cod, only very low levels were obtained at night in tilapia and no melatonin could be measured from isolated pineal glands in catfish. Together, these findings suggest that mechanisms involved in the perception of light and the transduction of this signal through the circadian axis has changed in teleosts possibly as a reflection of the photic environment in which they have evolved in. [Abstract]

Papis K, Poleszczuk O, Wenta-Muchalska E, Modlinski JA
Melatonin effect on bovine embryo development in vitro in relation to oxygen concentration.
J Pineal Res. 2007 Nov;43(4):321-6.
Melatonin promotes mouse embryo development in vitro. An effect of melatonin on bovine embryo development is described here. Slaughterhouse derived oocytes were subjected to standard in vitro maturation and fertilization procedures. Presumptive zygotes were cultured for 2 days in CR1aaLA medium supplemented with melatonin (10(-4) m) or without melatonin (control). Culture was performed under two different gas atmospheres containing physiological (7%) or atmospheric (20%) oxygen concentrations (2x2 factorial analysis). After day 2, embryos from each treatment group developed to at least four-cell stage, were cultured without melatonin until day 10 at optimum 7% O2 atmosphere. Blastocyst formation rates of presumptive zygotes and of four-cell embryos were calculated for each group. Significant interactions between oxygen tension and the melatonin treatment were found. Out of four-cell embryos put into in vitro culture after initial incubation in medium containing melatonin, decreased blastocyst rate was observed in melatonin group (47.7%) compared with control (67.7%; P=0.0327) when lower oxygen concentration was applied. A beneficial effect of melatonin was observed in 20% O2: out of 61 embryos, 42 (68.9%) developed to the blastocyst stage after treatment in melatonin versus 32 of 63 (50.8%; P=0.0458) blastocysts that developed in control group. In conclusion, beneficial or harmful effects of melatonin on bovine embryo development in vitro were observed, depending on the oxygen tension during the treatment. [Abstract]

Tan DX, Manchester LC, Terron MP, Flores LJ, Tamura H, Reiter RJ
Melatonin as a naturally occurring co-substrate of quinone reductase-2, the putative MT3 melatonin membrane receptor: hypothesis and significance.
J Pineal Res. 2007 Nov;43(4):317-20.
The nature of the MT3 melatonin receptor/binding site has been a long pondered mystery for scientists. Even though it is a presumptive membrane receptor, neither its transduction cascade nor its biological consequences, after its stimulation, have been uncovered. Moreover, solid data support the idea that the MT3 melatonin binding site is an enzyme, quinone reductase 2 (QR2), rather than a membrane melatonin receptor. Based on the data available and our preliminary studies, we hypothesize that melatonin is a co-substrate of QR2. We surmise that melatonin binds to a co-substrate binding site (MT3 binding site) donating an electron to the enzyme co-factor, flavin adenine dinucleotide (FAD). FAD can be reduced to either FADH or FADH2 while melatonin is converted to N1-acetyl-N2-formyl-5-methoxykynuramine and/or cyclic 3-hydroxymelatonin. QR2 is considered to be a detoxifying and antioxidant enzyme and its behavior changes depending on available co-substrates. As a naturally occurring substance, melatonin's levels fluctuate with the light/dark cycle, with aging and with health/disease state. As a result, these alterations in melatonin production under physiological or pathological conditions would probably influence the activity of QR2. [Abstract]

Morera AL, Abreu P
Daytime/night-time and summer/winter melatonin and malondialdehyde rhythms: an inverse relationship.
J Pineal Res. 2007 Oct;43(3):313-4. [Abstract]

Subramanian P, Mirunalini S, Dakshayani KB, Pandi-Perumal SR, Trakht I, Cardinali DP
Prevention by melatonin of hepatocarcinogenesis in rats injected with N-nitrosodiethylamine.
J Pineal Res. 2007 Oct;43(3):305-12.
N-nitrosodiethylamine (NDEA) is a potent carcinogenic agent that induces liver cancer. To evaluate the chemopreventive function of melatonin in this experimental model, Wistar male rats received a single i.p. injection of NDEA or vehicle followed by weekly s.c. injections of carbon tetrachloride or vehicle for 6 weeks. Melatonin (5 mg/kg body weight) or its vehicle (0.5 mL saline) was given i.p. on a daily basis 2 hr before lights off for 20 wk. At the end of this period the rats were killed and liver and blood samples were taken for histological and biochemical studies. As markers for liver function, the activity of aspartate transaminase (AST) and alanine transaminase (ALT) and the levels of alpha-fetoprotein were measured in serum. To assess lipid peroxidation and the antioxidant status in liver and blood, the levels of thiobarbituric acid reactive substances (TBARS) and of reduced glutathione (GSH) were measured. The activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) was assessed in liver and erythrocyte fraction of NDEA-treated rats. NDEA administration inhibited body weight, macro- and microscopically detectable liver tumors and increased levels of plasma AST, ALT and alpha-fetoprotein. NDEA treatment decreased liver TBARS levels and CAT and SOD activities and increased liver GSH levels and GST and GPx activities. Plasma TBARS were augmented, while plasma GSH levels and the activities of erythrocyte CAT, SOD, GST and GPx decreased, in NDEA-treated rats. Melatonin administration significantly curtailed tumor development and counteracted all the biochemical effects. [Abstract]

St Hilaire MA, Gronfier C, Zeitzer JM, Klerman EB
A physiologically based mathematical model of melatonin including ocular light suppression and interactions with the circadian pacemaker.
J Pineal Res. 2007 Oct;43(3):294-304.
The rhythm of plasma melatonin concentration is currently the most accurate marker of the endogenous human circadian pacemaker. A number of methods exist to estimate circadian phase and amplitude from the observed melatonin rhythm. However, almost all these methods are limited because they depend on the shape and amplitude of the melatonin pulse, which vary among individuals and can be affected by environmental influences, especially light. Furthermore, these methods are not based on the underlying known physiology of melatonin secretion and clearance, and therefore cannot accurately quantify changes in secretion and clearance observed under different experimental conditions. A published physiologically-based mathematical model of plasma melatonin can estimate synthesis onset and offset of melatonin under dim light conditions. We amended this model to include the known effect of melatonin suppression by ocular light exposure and to include a new compartment to model salivary melatonin concentration, which is widely used in clinical settings to determine circadian phase. This updated model has been incorporated into an existing mathematical model of the human circadian pacemaker and can be used to simulate experimental protocols under a number of conditions. [Abstract]

Stokkan KA, van Oort BE, Tyler NJ, Loudon AS
Adaptations for life in the Arctic: evidence that melatonin rhythms in reindeer are not driven by a circadian oscillator but remain acutely sensitive to environmental photoperiod.
J Pineal Res. 2007 Oct;43(3):289-93.
In reindeer Rangifer tarandus, a high latitude species, the rhythmic production of melatonin periodically dissipates under natural photoperiods when, in mid-winter, there is near permanent darkness and again, in summer, when there is permanent light. In spring and autumn, as expected, melatonin production reflects the ambient light:dark (LD) cycle. We investigated the expression of circadian mechanisms on blood levels of melatonin in reindeer. Two experiments were conducted in which animals were transferred from natural photic conditions into continuous darkness for 3 days: (i) in February, when they had been exposed to an LD cycle (11L:13D) and (ii) in July, when they had been exposed to permanent light. In July, plasma levels of melatonin rose abruptly on exposure to darkness but then declined over 24 hr before displaying a second rise and decline over the following 36 hr. In contrast, in February, levels of melatonin rose abruptly but then remained elevated for more than 60 hr in darkness. Melatonin secretion upon exposure to darkness did not conform to a circadian pattern and did not, therefore, support the hypothesis that pineal activity in reindeer is tightly regulated by circadian mechanisms. Instead the secretion of melatonin appeared to be acutely and directly sensitive to ambient lighting. The results are consistent with a model in which Arctic resident animals have adapted to extreme photic conditions by disconnecting the generation of the pineal melatonin signal from their circadian machinery and relying, instead, on its being driven by the LD cycle for just a few weeks annually in spring and autumn. [Abstract]

Rodriguez-Osorio N, Kim IJ, Wang H, Kaya A, Memili E
Melatonin increases cleavage rate of porcine preimplantation embryos in vitro.
J Pineal Res. 2007 Oct;43(3):283-8.
Melatonin has been used to promote in vitro embryo development in different species. This study determined the effects of melatonin on in vitro porcine embryo development; in particular, cleavage rate, blastocyst rate, and blastocyst cell number. Starting 5 hr after insemination, porcine zygotes were cultured in porcine zygote medium 3 (PZM-3) culture medium supplemented with melatonin at increasing concentrations (10(-12) M, 10(-9) M, 10(-6) M, 10(-3) M). Melatonin at a concentration of 10(-9) M had a positive effect on cleavage rates, while the highest concentration of melatonin (10(-3) M) significantly decreased cleavage rates. Although blastocyst rates were not increased by 10(-9) M melatonin, blastocyst cell numbers were significantly higher for embryos subjected to 10(-9) M melatonin. The expression levels of the pro-apoptotic gene BAX and anti-apoptotic gene BCL2L1 in blastocysts were not affected by the presence of melatonin in the culture medium. To further study the protective properties of 10(-9) M melatonin against stressful conditions, hydrogen peroxide (0.01 mm) and heat (40 degrees C) were used during embryo culture. The addition of melatonin to embryos subjected to 40 degrees C for 3 hr increased cleavage rates, but had no protective effect for embryos subjected to 0.01 mm H(2)O(2), probably because the physiological levels of melatonin could not counteract the pharmacological levels of H(2)O(2). Our data indicate that 10(-9) M melatonin has a positive effect on porcine embryo cleavage rates and blastocyst total cell numbers and it might have a protective effect against heat stress. [Abstract]

de Lima VR, Caro MS, Tavares MI, Creczynski-Pasa TB
Melatonin location in egg phosphatidylcholine liposomes: possible relation to its antioxidant mechanisms.
J Pineal Res. 2007 Oct;43(3):276-82.
Although it is known that the antioxidant properties of melatonin can be modulated by its effect on membrane fluidity, there are few studies on this subject reported in the literature and they are controversial. In this study, viscosimetry and nuclear magnetic resonance (NMR) techniques were used to determine melatonin's effect and location on egg phosphatidylcholine bilayers mobility. Melatonin decreases the dynamic viscosity of the lipid dispersion. (31)P-NMR line width analysis indicated that melatonin induces a slight but uniform restriction of the lipid motional freedom in the polar head. However, melatonin changes in choline (13)C dynamics was only observed through chemical shift analysis. On the other hand, melatonin can induce an increase in the lipid nonpolar chain mobility, as observed by (13)C and (1)H relaxation time analysis. These results suggest the interfacial location of melatonin in the membrane. Additionally, the results of the analysis of the lipid (1)H-fitted exponential relaxation times suggest that melatonin promotes a molecular rearrangement of the bilayers. The melatonin effect and location in the lipid membrane may explain its antioxidant properties against lipid peroxidation induced by reactive species. [Abstract]

Ruiz-Rabelo JF, V�zquez R, Perea MD, Cruz A, Gonz�lez R, Romero A, Mu�oz-Villanueva MC, T�nez I, Montilla P, Muntan� J, Padillo FJ
Beneficial properties of melatonin in an experimental model of pancreatic cancer.
J Pineal Res. 2007 Oct;43(3):270-5.
Pancreatic cancer is a major health problem because of the aggressiveness of the disease and the lack of effective systemic therapies. Melatonin has antioxidant activity and prevents experimental genotoxicity. However, the effect of melatonin in pancreatic cancer has not been tested. Pancreatic carcinogenesis was induced by N-nitrosobis (2-oxopropyl)amine (BOP) in Syrian hamsters. Melatonin was administered during the BOP-induction phase (12 wk) and/or following the postinduction phase (12 wk). Different parameters of oxidative stress including lipid peroxides (LPO) and antioxidants (superoxide dismutase, catalase, reduced glutathione and glutathione peroxidase) were determined in pancreatic tissue. Also, the presence of atypical hyperplasia (AH), well and moderately differentiated adenomacarcinoma (ADC-WD and ADC-MD, respectively) were studied. The administration of BOP induced an intense oxidative stress and ADC induction in the pancreas. The administration of melatonin during the induction or postinduction phase reduced LPO and improved the antioxidant status, as well as drastically reducing the presence of ADC but some AH remained. In conclusion, treatment with melatonin reduced oxidative damage and cancer nodules induced by BOP in the pancreas. [Abstract]

Pe�a C, Rincon J, Pedreanez A, Viera N, Mosquera J
Chemotactic effect of melatonin on leukocytes.
J Pineal Res. 2007 Oct;43(3):263-9.
Melatonin seems to be an important stimulatory factor of the immune system. This indolamine is capable of inducing activation of leukocytes. Tissue leukocyte infiltration is a key feature of inflammatory and immune responses; however, there is no information about the effect of melatonin on leukocyte chemotaxis. Therefore, the aim of this study was to examine the in vitro and in vivo effects of melatonin on leukocyte chemotaxis, on modulation of leukocyte chemotaxis to other chemoattractants and on the in vivo induction of leukocyte chemokines. Neutrophils and mononuclear leukocytes (PBMC) were isolated by a discontinuous gradient on Hystopaque. Chemotaxis was performed in blind well Boyden's chambers. In vivo chemotaxis was determined after intraperitoneal injection of melatonin into rats. Leukocyte chemotactic response and leukocyte chemokine expression were determined in human volunteers treated with 20 mg daily of melatonin. Increased neutrophils and PBMC chemotaxis in response to 1.2 nm melatonin was observed in vitro. Peritoneal leukocytes were found increased after melatonin injection. Humans treated with melatonin showed an increased neutrophil chemotactic response to a physiological chemoattractant and increased expression of intracellular chemokines; however, decreased chemotactic response and no chemokine expression were observed in PBMC. These data suggest that melatonin could have a relevant role during the tissue leukocyte infiltration in inflammatory and immune responses. [Abstract]

Kokkola T, Vaittinen M, Laitinen JT
Inverse agonist exposure enhances ligand binding and G protein activation of the human MT1 melatonin receptor, but leads to receptor down-regulation.
J Pineal Res. 2007 Oct;43(3):255-62.
Melatonin binds and activates G protein-coupled melatonin receptors. The density and affinity of the endogenous melatonin receptors change throughout the 24-hr day, and the exposure of recombinant melatonin receptors to melatonin often results in desensitization of the receptors. Receptor density, G protein activation and expression level were analyzed in CHO cell lines stably expressing the human MT1 receptors after 1 or 72 hr of exposure to melatonin (agonist, 10 nm) and luzindole (antagonist/inverse agonist, 10 microm). The 72-hr exposure to luzindole significantly increased the apparent receptor density in cell lines with both high and low MT1 receptor expression levels (MT1(high) and MT1(low) cells, respectively). In the constitutively active MT1(high) cells, luzindole pretreatment also stimulated the functional response to melatonin in [(35)S]GTPgammaS binding assays, whereas melatonin pretreatment attenuated the functional response at both time points. Receptor ELISA was used to analyze the cell membrane and total expression level of the MT1 receptor in intact and permeabilized cells, respectively. Luzindole pretreatment decreased the total cellular level of MT1 receptor in the MT1(high) cells at both time points but increased the cell surface expression of MT1 receptor at 72 hr. Melatonin significantly decreased MT1 receptor cell surface expression only in MT1(high) cells after a 1-hr treatment. These results indicate that melatonin treatment desensitizes MT1 receptors, whereas luzindole increases ligand binding and G-protein activation. Luzindole also stimulates downregulation of the MT1 receptor protein, interfering with the synthesis and/or degradation of the receptor. [Abstract]

Sharma R, McMillan CR, Niles LP
Neural stem cell transplantation and melatonin treatment in a 6-hydroxydopamine model of Parkinson's disease.
J Pineal Res. 2007 Oct;43(3):245-54.
Melatonin has multiple roles including neuroprotection. Melatonin signaling involves diverse targets including two G-protein-coupled receptors, MT(1) and MT(2), which have both been localized to the nigrostriatal pathway. Previous studies in our laboratory demonstrated preservation of tyrosine hydroxylase immunoreactivity, following chronic treatment with a physiological dose of melatonin, in the 6-hydroxydopamine rat model of Parkinson's disease. Additionally, we reported the presence of the melatonin MT(1) receptor subtype in cultured C17.2 neural stem cells (NSCs). In the present study, we examined the effects of C17.2 NSC transplantation on dopaminergic denervation following 6-hydroxydopamine lesioning in the rat striatum. Moreover, based on our detection of the MT(1) in these cells, we examined the effects of combined C17.2 NSC transplantation and melatonin treatment, following striatal lesioning. Behavioral studies indicated a marked inhibition of apomorphine-induced rotations in lesioned animals that received C17.2 NSC transplantation, melatonin, or the combined regimen. In addition, these treatments resulted in a significant protection of tyrosine hydroxylase immunoreactivity in the striatum and substantia nigra of lesioned animals, when compared with untreated controls. Lesioned animals treated with C17.2 NSCs, melatonin or a combination of both agents exhibited no significant differences in the number of tyrosine hydroxylase-positive cells in the substantia nigra or ventral tegmental area ipsilateral or contralateral to the lesioned striatum. These findings suggest that stem cell therapy and concomitant use of neuroprotective agents such as melatonin could be a viable approach in Parkinson's disease. [Abstract]

Mart�n V, Herrera F, Garc�a-Santos G, Antol�n I, Rodriguez-Blanco J, Medina M, Rodriguez C
Involvement of protein kinase C in melatonin's oncostatic effect in C6 glioma cells.
J Pineal Res. 2007 Oct;43(3):239-44.
Classical anticancer therapies often are ineffective in patients with malignant glioma who have a survival of <1 year. Our previous studies showed a potent inhibitory effect of melatonin on glioma cell proliferation. This effect seems to be mediated by the well-known antioxidant properties of this molecule and the negative regulation of some intracellular effectors, such as the kinase Akt or the transcription factor nuclear factor (NF)-kappaB. Finally, protein kinase C (PKC) also seems to be implicated in this effect although the intracellular pathways involved have not been elucidated. In this study, we analyzed the role of PKC in the regulation by melatonin of intracellular effectors leading to inhibition of cell proliferation. Activation of PKC by incubation with triphorbol ester acetate (TPA) blocks the inhibitory effect of melatonin on Akt and NF-kappaB activity. Moreover, incubation with melatonin induces a decrease in p21 expression in these cells that is partially blocked by co-incubation with TPA. Taken together, these results suggest that melatonin's oncostatic effect on glioma cells is mediated, at least in part, by the inhibition of PKC activity which, in turn, results in Akt and NF-kappaB activity inhibition and modulation of cell cycle-related gene expression. [Abstract]

Liu YJ, Zhuang J, Zhu HY, Shen YX, Tan ZL, Zhou JN
Cultured rat cortical astrocytes synthesize melatonin: absence of a diurnal rhythm.
J Pineal Res. 2007 Oct;43(3):232-8.
Melatonin not only plays a major role in the regulation of circadian rhythms, but is also involved in antioxidative defense and immunomodulation. Circulating melatonin levels are derived primarily from the pineal gland while other sources of melatonin have also been reported. Here, we show for the first time that astrocytes from the rat cortex and glioma C6 cell line synthesize melatonin in vitro. In addition, we show the presence of serotonin, the precursor of melatonin and the two key enzymes in the pathway of melatonin synthesis, i.e. N-acetyltransferase and hydroxyndole-O-methyltransferase in the cultured rat cortical astrocytes. Release of melatonin into the culture medium showed no diurnal changes. These point to astrocytes as a local source of melatonin in the rat brain. Its exact physiological function remains a topic for future studies. [Abstract]

Baydas G, Koz ST, Tuzcu M, Etem E, Nedzvetsky VS
Melatonin inhibits oxidative stress and apoptosis in fetal brains of hyperhomocysteinemic rat dams.
J Pineal Res. 2007 Oct;43(3):225-31.
Moderate hyperhomocysteinemia is a risk factor for neurodegenerative diseases and complications during pregnancy. Increased homocysteine levels during pregnancy may elevate developmental risk on fetal brain structure and function. However, little is known about the mechanism of action of homocysteine on the degeneration of the fetal brain. Hence in this study, we examined the effects of maternal hyperhomocysteinemia on oxidative stress and apoptosis in brain tissues and investigated whether administration of melatonin to the mother would prevent homocysteine-induced oxidative cerebral damage in pups. Hyperhomocysteinemia was induced in female rats by administration of methionine at a dose of 1 g/kg body weight dissolved in drinking water during pregnancy. Some animals received methionine plus 10 mg/kg/day melatonin subcutaneously throughout pregnancy. After delivery, the level of lipid peroxidation (malondialdehyde + 4-hydroxyalkenals) was determined in different subfractions of pup brains. Furthermore, DNA fragmentation, levels of Bcl-2 protein and p53 mRNA expression were determined to evaluate apoptosis. Significant elevation was found in the levels of lipid peroxidation in subcellular fractions of the brain of pups of hyperhomocysteinemic dams. Increased DNA fragmentation and p53 mRNA expression was observed in the brain of pups of homocysteine-treated rats, while a significant reduction was seen in the levels of anti-apoptotic Bcl-2 levels. Melatonin administration prevented markers of oxidative stress and biochemical signs of apoptosis. In conclusion, therapeutic administration of melatonin protects against the induction of oxidative stress and neural tissue injury and might prevent congenital malformations of fetal brain caused by maternal hyperhomocysteinemia. [Abstract]

Navara KJ, Nelson RJ
The dark side of light at night: physiological, epidemiological, and ecological consequences.
J Pineal Res. 2007 Oct;43(3):215-24.
Organisms must adapt to the temporal characteristics of their surroundings to successfully survive and reproduce. Variation in the daily light cycle, for example, acts through endocrine and neurobiological mechanisms to control several downstream physiological and behavioral processes. Interruptions in normal circadian light cycles and the resulting disruption of normal melatonin rhythms cause widespread disruptive effects involving multiple body systems, the results of which can have serious medical consequences for individuals, as well as large-scale ecological implications for populations. With the invention of electrical lights about a century ago, the temporal organization of the environment has been drastically altered for many species, including humans. In addition to the incidental exposure to light at night through light pollution, humans also engage in increasing amounts of shift-work, resulting in repeated and often long-term circadian disruption. The increasing prevalence of exposure to light at night has significant social, ecological, behavioral, and health consequences that are only now becoming apparent. This review addresses the complicated web of potential behavioral and physiological consequences resulting from exposure to light at night, as well as the large-scale medical and ecological implications that may result. [Abstract]

Todisco M
Melatonin makes splenectomy unnecessary in two patients with idiopathic thrombocytopenic purpura refractory to corticosteroids.
J Pineal Res. 2007 Sep;43(2):214. [Abstract]

Toma CD, Svoboda M, Arrich F, Ekmekcioglu C, Assadian O, Thalhammer T
Expression of the melatonin receptor (MT) 1 in benign and malignant human bone tumors.
J Pineal Res. 2007 Sep;43(2):206-13.
The beneficial effects of melatonin on bone homeostasis have been shown in various diseases. As this indoleamine causes dose-dependent modulation of bone-forming osteoblast and bone-resorbing osteoclast activities by receptor-independent and -dependent pathways, we investigated the expression of G-protein-coupled melatonin receptors (MTs) in malignant and non-malignant human bone lesions. By TaqMan polymerase chain reaction (PCR), we analyzed 30 specimens from osteosarcoma and 11 from benign bone tumors for MT1-mRNA expression. Furthermore, we determined mRNA expression levels of the osteoclast activity-stimulating receptor activator of nuclear factor-kappa B ligand (RANKL) and its counterpart osteoprotegerin (OPG). Although mean MT1-mRNA levels were similar (P = 0.596) in malignant (4.39 +/- 4.98-fold) and benign samples (4.64 +/- 6.81-fold), the highest MT1-mRNA levels (up to 27-fold) were observed in individual osteosarcomas, particularly, in two specimens of patients with local recurrence of the tumor. Moreover, mean RANKL- and OPG-mRNA levels were similar in malignant and benign specimens (RANKL: 7.38 +/- 9.61-fold versus 3.57 +/- 3.11-fold, P = 0.207; OPG: 23.45 +/- 32.76 versus 8.07 +/- 7.23-fold, P = 0.133). Again, highest RANKL- and OPG-mRNA levels (up to 41- and 160-fold, respectively) were observed in individual osteosarcomas. Expression of MT1-mRNA was confirmed in two human osteosarcoma cell lines (HOS, MG63). High expression levels of MT1-mRNA together with low OPG-mRNA were found in both osteosarcoma cell lines, while in normal human osteoblasts and bone marrow stromal cells, high OPG-mRNA levels were associated with low MT1-mRNA levels. These data on the abundant expression of MT1-mRNA in human bone tumors and osteosarcoma cells lines suggest an important role for MT1 in bone pathology. [Abstract]

Garc�a-Navarro A, Gonz�lez-Puga C, Escames G, L�pez LC, L�pez A, L�pez-Cantarero M, Camacho E, Espinosa A, Gallo MA, Acu�a-Castroviejo D
Cellular mechanisms involved in the melatonin inhibition of HT-29 human colon cancer cell proliferation in culture.
J Pineal Res. 2007 Sep;43(2):195-205.
The antiproliferative and proapoptotic properties of melatonin in human colon cancer cells in culture were recently reported. To address the mechanisms involved in these actions, HT-29 human colon cancer cells were cultured in RPMI 1640 medium supplemented with fetal bovine serum at 37 degrees C. Cell proliferation was assessed by the incorporation of [(3)H]-thymidine into DNA. Cyclic nucleotide levels, nitrite concentration, glutathione peroxidase and reductase activities, and glutathione levels were assessed after the incubation of these cells with the following drugs: melatonin membrane receptor agonists 2-iodo-melatonin, 2-iodo-N-butanoyl-5-methoxytryptamine, 5-methoxycarbonylamino-N-acetyltryptamine (GR-135,531), and the antagonists luzindole, 4-phenyl-2-propionamidotetralin, and prazosin; the melatonin nuclear receptor agonist CGP 52608, and four synthetic kynurenines analogs to melatonin 2-acetamide-4-(3-methoxyphenyl)-4-oxobutyric acid, 2-acetamide-4-(2-amino-5-methoxyphenyl)-4-oxobutyric acid, 2-butyramide-4-(3-methoxyphenyl)-4-oxobutyric acid and 2-butyramide-4-(2-amino-5-methoxyphenyl)-4-oxobutyric acid. The results show that the membrane receptors are not necessary for the antiproliferative effect of melatonin and the participation of the nuclear receptor in this effect is suggested. Moreover, the antioxidative and anti-inflammatory actions of melatonin, counteracting the oxidative status and reducing the production of nitric oxide by cultured HT-29 cells seem to be directly involved in the oncostatic properties of melatonin. Some of the synthetic kynurenines exert higher antiproliferative effects than melatonin. The results reinforce the clinical interest of melatonin due to the different mechanisms involved in its oncostatic role, and suggest a new synthetic pathway to obtain melatonin agonists with clinical applications to oncology. [Abstract]

Ackermann K, Dehghani F, Bux R, Kauert G, Stehle JH
Day-night expression patterns of clock genes in the human pineal gland.
J Pineal Res. 2007 Sep;43(2):185-94.
Rhythm generation within the mammalian circadian system is achieved by clock genes and their protein products. As an integral part of this system, the pineal gland serves the need to tune the body to the temporal environment by the rhythmic synthesis and release of melatonin. A number of human disorders and syndromes are associated with alterations in circadian rhythms of clock genes and their protein products and/or a dysfunction in melatonin synthesis. In the human, little is known about the molecular signature of time management. Pineal tissue from regular autopsies was allocated to asserted time-of-death groups (dawn, day, dusk, night), and analyzed by RT-PCR, immunoblotting, immunohistochemistry, and confocal laser scanning microscopy for expression of clock genes. Despite the observed diurnal rhythms in activity of the arylalkylamine N-acetyltransferase and in melatonin content, mRNA levels for the clock genes Period1, Cryptochrome1, Clock, and Bmal1, and also amounts of corresponding clock gene proteins showed no differences between time- of-death groups. In contrast, a time-of-day-dependent nucleocytoplasmic shuttling of clock gene proteins was detected. These data confirm the minor importance of a transcriptional regulation for dynamics in the human pineal gland, and offer a novel twist in the molecular competence of clock gene proteins. [Abstract]

G�genur I, Middleton B, Burgdorf S, Rasmussen LS, Skene DJ, Rosenberg J
Impact of sleep and circadian disturbances in urinary 6-sulphatoxymelatonin levels, on cognitive function after major surgery.
J Pineal Res. 2007 Sep;43(2):179-84.
Sleep and circadian disturbances may underlie cognitive dysfunction after major surgery. The aim of this study was to examine the association between sleep and circadian disturbances (as assessed by changes in the melatonin rhythm) and postoperative cognitive dysfunction (POCD). We measured subjective and objective sleep quality, excretion of the major metabolite of melatonin, 6-sulphatoxymelatonin (aMT6s) in urine and cognitive function before and 4 days after major abdominal surgery in 36 patients. Subjective sleep quality was measured by visual analogue scale, objective sleep quality was measured by actigraphy, and cognitive function was assessed by neuropsychological testing. Eighteen patients (50%) had POCD on day 4 after surgery. At that time, the excretion of aMT6s was disturbed with significantly higher daytime excretion and a reduced night/day ratio compared with the preoperative measure (P = 0.05). Patients with POCD had significantly worse sleep quality and more night awakenings (P < 0.05) but we found no significant differences in day time (06:00-22:00 hr), night-time (22:00-06:00 hr) or total aMT6s excretion (mug/24 hr). A significant correlation was found between the total excretion of aMT6s and actigraphically measured sleep efficiency (r(s) = 0.45, P = 0.03) and wakefulness after sleep onset (r(s) = -0.44, P = 0.04). In conclusion, POCD was associated with worse subjective sleep quality and more awakenings. Circadian rhythmicity as assessed by aMT6s excretion was disturbed after surgery but we were unable to show an association with POCD. Strategies to improve postoperative sleep quality should be investigated in the future. [Abstract]

Kurcer Z, Oguz E, Ozbilge H, Baba F, Aksoy N, Celik H, Cakir H, Gezen MR
Melatonin protects from ischemia/reperfusion-induced renal injury in rats: this effect is not mediated by proinflammatory cytokines.
J Pineal Res. 2007 Sep;43(2):172-8.
The pathophysiologic mechanisms leading to acute ischemic renal failure are not completely understood. Melatonin, a compound with well-known antioxidant properties, reduces IR-induced renal injury. The purpose of the present study was to investigate the changes in levels of tumor necrosis factor (TNF)-alpha, IL-beta, and IL-6 in postischemic reperfused renal tissue, and to determine whether the protective effect of melatonin is related the modulation of the production of these inflammatory molecules. Male Wistar albino rats were unilaterally nephrectomized and subjected to 1 hr of renal pedicle occlusion followed by 2 hr or 24 hr of reperfusion. Melatonin (10 mg/kg, i.p.) or vehicle was administrated at 10 min prior to ischemia. After 24 hr of the reperfusion, following decapitation, kidney samples were taken both for histologic examination and for the determination of malondialdehyde (MDA), myeloperoxidase (MPO) activity, total antioxidant capacity (TAC), total oxidative stress (TOS), creatinine, and blood urea nitrogen (BUN). These were measured in serum samples. TNF-alpha, IL-beta, and IL-6 were measured in kidney samples after 2 hr of reperfusion. IR caused a significant increase in renal MDA, MPO, TOS, creatinine, and BUN while decrease TAC without any change in TNF-alpha, IL-beta, and IL-6 levels. Melatonin treatment reduced the biochemical indices without any change in the cytokine levels and ameliorated histopathologic alterations induced by IR. The protective effect of melatonin on IR-induced renal injury is related to its antioxidant properties but not to proinflammatory cytokines. [Abstract]

Lin AM, Fang SF, Chao PL, Yang CH
Melatonin attenuates arsenite-induced apoptosis in rat brain: involvement of mitochondrial and endoplasmic reticulum pathways and aggregation of alpha-synuclein.
J Pineal Res. 2007 Sep;43(2):163-71.
In the present study, the protective effect of melatonin on sodium arsenite (arsenite)-induced apoptosis was investigated. Local infusion of arsenite elevated lipid peroxidation and depleted glutathione content in the infused substantia nigra (SN), as well as reduced striatal dopamine content. Systemic administration of melatonin diminished arsenite-induced oxidative injury. Furthermore, melatonin attenuated arsenite-induced increases in heat shock protein 70 and heme oxygenase-1 as well as phosphorylation of p38 mitogen-activated protein kinase and elevations in cyclooxygenase II and inducible nitric oxide synthase expression. Inhibition by melatonin of arsenite-induced apoptosis was determined by its attenuation of DNA fragmentation and terminal deoxytransferase-mediated dUTP-nick end labeling's positive cells in the infused SN of melatonin-treated rats. Melatonin reduced arsenite-induced apoptosis through mitochondrial and endoplasmic reticulum (ER) pathways. In the mitochondrial pathway, systemic melatonin inhibited arsenite-induced elevations in Bcl-2 and cytosolic cytochrome c as well as arsenite-induced reductions in procaspase-3 levels and elevations in active caspase-3 levels in the infused SN. Regarding the ER pathway, melatonin attenuated arsenite-induced elevations in activating transcription factor-4, CCAAT/enhancer binding protein (C/EBP) homologues protein, X-bon binding protein (XBP-1) and cytosolic immunoglobulin binding protein (BIP) as well as reductions in procaspase 12 levels. Moreover, aggregation of alpha-synuclein was reduced in the arsenite-infused SN of melatonin-treated rats. Our in vitro data showed that melatonin ameliorated arsenite-induced lipid peroxidation. Taken together, our data suggest that melatonin is neuroprotective against arsenite-induced oxidative injury in the nigrostriatal dopaminergic system of rat brain. Furthermore, the neuroprotective effects by melatonin on arsenite-induced apoptosis were mediated via inhibiting both mitochondrial and ER pathways. Accordingly, melatonin may be therapeutically useful for the treatment of arsenite-induced apoptosis in central nervous system. [Abstract]

Radogna F, Paternoster L, Albertini MC, Cerella C, Accorsi A, Bucchini A, Spadoni G, Diamantini G, Tarzia G, De Nicola M, D'Alessio M, Ghibelli L
Melatonin antagonizes apoptosis via receptor interaction in U937 monocytic cells.
J Pineal Res. 2007 Sep;43(2):154-62.
Among the non-neurological functions of melatonin, much attention is being directed to the ability of melatonin to modulate the immune system, whose cells possess melatonin-specific receptors and biosynthetic enzymes. Melatonin controls cell behaviour by eliciting specific signal transduction actions after its interaction with plasma membrane receptors (MT(1), MT(2)); additionally, melatonin potently neutralizes free radicals. Melatonin regulates immune cell loss by antagonizing apoptosis. A major unsolved question is whether this is due to receptor involvement, or to radical scavenging considering that apoptosis is often dependent on oxidative alterations. Here, we provide evidence that on U937 monocytic cells, apoptosis is antagonized by melatonin by receptor interaction rather than by radical scavenging. First, melatonin and a set of synthetic analogues prevented apoptosis in a manner that is proportional to their affinity for plasma membrane receptors but not to their antioxidant ability. Secondly, melatonin's antiapoptotic effect required key signal transduction events including G protein, phospholipase C and Ca(2+) influx and, more important, it is sensitive to the specific melatonin receptor antagonist luzindole. [Abstract]

Recent Articles in Developmental Dynamics: An Official Publication of the American Association of Anatomists

Warkman AS, Yatskievych TA, Hardy KM, Krieg PA, Antin PB
Myocardin expression during avian embryonic heart development requires the endoderm but is independent of BMP signaling.
Dev Dyn. 2007 Dec 10;
Myocardin, a serum response factor cofactor, plays an important role in regulating heart and smooth muscle development. To investigate myocardin function during early stages of heart development, we isolated the chicken orthologue of myocardin and characterized its expression between Hamburger and Hamilton stages 3 and 15. At stage 4, myocardin transcripts are detected in the lateral and extraembryonic mesoderm, become progressively localized to the precardiac mesoderm and the differentiated myocardium and are also seen in smooth muscle cells of the developing vascular plexus. Surprisingly, myocardin expression within the developing chicken embryo precedes that of the homeodomain transcription factor Nkx2.5. Embryonic dissection studies demonstrate that signals from the endoderm are required for myocardin expression within the precardiac mesoderm. However, unlike Nkx2.5, myocardin expression is not regulated by bone morphogenetic protein (BMP) signaling. These results suggest that initial expression of myocardin in the precardiac mesoderm is regulated by a signaling pathway that is parallel to, and independent of, Nkx2.5 expression. Developmental Dynamics, 2008. (c) 2007 Wiley-Liss, Inc. [Abstract]

Singh S, Robinson M, Ismail I, Saha M, Auer H, Kornacker K, Robinson ML, Bates CM, McHugh KM
Transcriptional profiling of the megabladder mouse: A unique model of bladder dysmorphogenesis.
Dev Dyn. 2007 Dec 10;
Recent studies in our lab identified a mutant mouse model of obstructive nephropathy designated mgb for megabladder. Homozygotic mgb mice (mgb-/-) develop lower urinary tract obstruction in utero due to a lack of bladder smooth muscle differentiation. This defect is the result of a random transgene insertion/translocation into chromosomes 11 and 16. Transcriptional profiling identified a significantly over-expressed cluster of gene products located on the translocated fragment of chromosome 16 including urotensin II-related peptide (Urp), which was shown to be preferentially over-expressed in developing mgb-/- bladders. Pathway analysis of mgb microarray data indicated dysregulation of at least 60 gene products associated with smooth muscle development. In conclusion, the results of this study indicate that the molecular pathways controlling normal smooth muscle development are severely altered in mgb-/- bladders, and provide the first evidence that Urp may play a critical role in bladder smooth muscle development. Developmental Dynamics, 2008. (c) 2007 Wiley-Liss, Inc. [Abstract]

Cann GM, Guignabert C, Ying L, Deshpande N, Bekker JM, Wang L, Zhou B, Rabinovitch M
Developmental expression of LC3alpha and beta: Absence of fibronectin or autophagy phenotype in LC3beta knockout mice.
Dev Dyn. 2007 Dec 10;
Murine light chain 3 (LC3) exists as two isoforms, LC3alpha and beta: LC3beta is an RNA-binding protein that enhances fibronectin (FN) mRNA translation, and is also a marker of autophagy. We report embryonic expression patterns for LC3alpha and LC3beta, with some overlap but notable differences in the brain, and in tissues of non-neuronal origin. LC3beta knockout (-/-) mice develop normally without a compensatory increase in LC3alpha. LC3beta-/- embryonic fibroblasts (MEFs) exhibit reduced FN synthesis but maintain wild type (WT) levels of FN protein. No significant changes in proteins associated with FN turnover, i.e., caveolin-1, LRP-1, or matrix metalloproteinases were identified. Autophagosomes form in amino acid-starved LC3beta-/-MEFs, and Caesarean-delivered pups survive as long as WT pups without an increase in LC3-related proteins linked to autophagy. These results suggest novel compensatory mechanisms for loss of LC3beta, ensuring proper FN accumulation and autophagy during fetal and neonatal life. Developmental Dynamics, 2008. (c) 2007 Wiley-Liss, Inc. [Abstract]

Hakm� A, Huber A, Doll� P, Schreiber V
The macroPARP genes parp-9 and parp-14 are developmentally and differentially regulated in mouse tissues.
Dev Dyn. 2007 Dec 10;
The macroPARPs Parp-9 and Parp-14 are macro domain containing poly(ADP-ribose) polymerases involved in transcriptional regulation in response to immunoregulatory cytokines. Their genes reside in the same locus (16B3), and the Parp-9 gene lies head-to-head and shares its promoter with the gene encoding its partner, Bbap. Here, we provide a detailed analysis of Parp-9, Parp-14, and Bbap expression during mouse development and adulthood. Parp-9 is developmentally regulated, and prominently expressed in the thymus and specific regions of the brain and gut. In adults, highest expression is maintained in the thymus and intestine. Parp-14 is more weakly expressed, mainly in the thymus during development and in adulthood. In addition, we show that Bbap is essentially coexpressed with Parp-9 during development and in adult mouse. However, the different levels of their transcripts detected in the developing brain and gut suggest that Bbap and Parp-9 display both common and independent tissue-specific regulations. Developmental Dynamics 2008. (c) 2007 Wiley-Liss, Inc. [Abstract]

Wagstaff LJ, Bellett G, Mogensen MM, M�nsterberg A
Multicellular rosette formation during cell ingression in the avian primitive streak.
Dev Dyn. 2007 Dec 10;
Cell movements are a fundamental feature during the development of multi-cellular organisms. In amniote gastrulation, cells ingress through the primitive streak, which identifies the anterior-posterior axis of the embryo. We investigated the cytoskeletal architecture during these morphogenetic processes and characterized microtubule organisation in whole chick embryos. This revealed the distribution of cells with polarized and radial microtubule (MT) arrays across different regions of the embryo. Cells in the epiblast usually displayed radial MT-arrays, while the majority of cells in the primitive streak had polarized MT-arrays. Within the primitive streak, many cells organized into groups and were arranged in rosette-like structures with a distinct centre characterized by an accumulation of actin. Extended confocal microscopy and three-dimensional image reconstruction identified tips of polarized cells that were protruding from the plane of rosettes, usually from the centre. We propose that organization into higher order structures facilitates cell ingression during gastrulation. Developmental Dynamics, 2008. (c) 2007 Wiley-Liss, Inc. [Abstract]

Itman C, Loveland KL
SMAD expression in the testis: An insight into BMP regulation of spermatogenesis.
Dev Dyn. 2007 Dec 10;
Bone morphogenetic proteins (BMPs), members of the transforming growth factor-beta superfamily, extensively influence events that establish male fertility, affecting germ cells and somatic cells throughout fetal and postnatal life. BMP signals are relayed by SMAD proteins, transcription factors that translocate to the nucleus upon ligand stimulation. We show that BMP signaling in the testis may be regulated by selective expression of BMP-responsive and inhibitory SMADs, with expression differing between the first wave and adult spermatogenesis. Smad1, Smad5, Smad8, Smad4, Smad6, and Smad7 expression is ubiquitous during testis development but becomes cell-specific in the adult. Furthermore, regulated SMAD6 protein expression at the onset of spermatogenesis suggests differential responsiveness of spermatogonial subpopulations to ligands. In vitro, immature Sertoli cells and spermatogonia transduce BMP2 and BMP4 signals by means of SMAD1, SMAD5, and SMAD8. Based on these findings, we extrapolate these data to interpret BMP mutant testis phenotypes in terms of SMAD availability for signal transduction. Developmental Dynamics 2008. (c) 2007 Wiley-Liss, Inc. [Abstract]

Bracken CM, Mizeracka K, McLaughlin KA
Patterning the embryonic kidney: BMP signaling mediates the differentiation of the pronephric tubules and duct in Xenopus laevis.
Dev Dyn. 2007 Dec 10;
The Bone morphogenetic proteins (BMPs) mediate a wide range of diverse cellular behaviors throughout development. Previous studies implicated an important role for BMP signaling during the differentiation of the definitive mammalian kidney, the metanephros. In order to examine whether BMP signaling also plays an important role during the patterning of earlier renal systems, we examined the development of the earliest nephric system, the pronephros. Using the amphibian model system Xenopus laevis, in combination with reagents designed to inhibit BMP signaling during specific stages of nephric development, we revealed an evolutionarily conserved role for this signaling pathway during renal morphogenesis. Our results demonstrate that conditional BMP inhibition after specification of the pronephric anlagen is completed, but prior to the onset of morphogenesis and differentiation of renal tissues, results in the severe malformation of both the pronephric duct and tubules. Importantly, the effects of BMP signaling on the developing nephron during this developmental window are specific, only affecting the developing duct and tubules, but not the glomus. These data, combined with previous studies examining metanephric development in mice, provide further support that BMP functions to mediate morphogenesis of the specified renal field during vertebrate embryogenesis. Specifically, BMP signaling is required for the differentiation of two types of nephric structures, the pronephric tubules and duct. Developmental Dynamics, 2008. (c) 2007 Wiley-Liss, Inc. [Abstract]

O'Farrell F, Esfahani SS, Engstr�m Y, Kylsten P
Regulation of the Drosophila lin-41 homologue dappled by let-7 reveals conservation of a regulatory mechanism within the LIN-41 subclade.
Dev Dyn. 2007 Dec 10;
Drosophila Dappled (DPLD) is a member of the RBCC/TRIM superfamily, a protein family involved in numerous diverse processes such as developmental timing and asymmetric cell divisions. DPLD belongs to the LIN-41 subclade, several members of which are micro RNA (miRNA) regulated. We re-examined the LIN-41 subclade members and their relation to other RBCC/TRIMs and dpld paralogs, and identified a new Drosophila muscle specific RBCC/TRIM: Another B-Box Affiliate, ABBA. In silico predictions of candidate miRNA regulators of dpld identified let-7 as the strongest candidate. Overexpression of dpld led to abnormal eye development, indicating t