5-HT5 Receptor Research -- Neurotransmitter.net

(Updated 8/10/04)

Nelson DL.
5-HT5 receptors.
Curr Drug Targets CNS Neurol Disord. 2004 Feb;3(1):53-8.
"The 5-HT(5) receptor family consists of two members designated as 5-HT(5A) and 5-HT(5B). To date the 5-HT(5A) receptor has been identified in the mouse, rat, and human. The 5-HT(5B) receptor also is expressed in the mouse and rat, but not in the human where the coding sequence is interrupted by stop codons. Both receptors are essentially limited in distribution to the central nervous system (CNS), although the 5-HT(5A) receptor has also been found on neurons and neuronal-like cells of the carotid body. Within the CNS the 5-HT(5A) receptor shows a relatively broad distribution, while the 5-HT(5B) receptor has a very restricted distribution. The 5-HT(5A) receptor has been demonstrated to couple to G proteins, and the primary coupling appears to be through Gi/o to inhibit adenylyl cyclase activity. The 5-HT(5) receptors have not been extensively characterized pharmacologically. Both receptors show their highest affinity for LSD, which appears to act as a partial agonist at the 5-HT(5A) receptor. Amongst agonist-like molecules, 5-CT (5-carboxamidotryptamine) also has high affinity and has greater potency and affinity at the 5-HT(5A) receptor than does 5-HT itself. Both [(125)I]LSD and [(5)H]5-CT have been used as radioligands to study the receptors in vitro. Nothing is known about the role of the 5-HT(5B) receptor in vivo. A mouse line has been developed where the 5-HT(5A) receptor has been knocked out and these animals have been shown to have a diminished response to LSD-induced increases in locomotion. The 5-HT(5) receptors remain as two of the least studied and understood of the 5-HT receptor subtypes." [Abstract]

Regis Grailhe, Gregg W. Grabtree, Rene Hen
Human 5-HT5 receptors: the 5-HT5A receptor is functional but the 5-HT5B receptor was lost during mammalian evolution
European Journal of Pharmacology 418 2001 157–167
We have isolated from a human genomic library the human 5-hydroxytryptamine 5-HT5A and 5-HT5B genes. The human 5-HT5A gene encodes a protein with similar characteristics to its mouse homologue. When expressed in monkey COS-7 cells, the human 5-HT5A receptor displayed a high affinity for tritiated 5-carbamidotryptamine ([3H]5-CT; Kd = 2.8 nM) and iodinated lysergic acid diethylamide ([125I])LSD; Kd = 187 pM) . These binding sites displayed the following displacement profile: Ergotamine > Methiothepin > 5-CT, Ritanserin > 5-HT. Reverse transcriptase polymerase chain reaction RT-PCR experiments revealed the presence of human 5-HT5A mRNA in the central nervous system but not in peripheral organs. When expressed in Xenopus oocytes, the 5-HT5A receptor was able to couple to the inwardly rectifying K+ channel, GIRK1. In contrast to the human 5-HT5A gene and the mouse 5-HT5B gene, the human 5-HT5B gene does not encode a functional protein because its coding sequence is interrupted by stop codons. Our results suggest, therefore, that the 5-HT5B receptor has been lost during evolution after the divergence between rodents and primates. The 5-HT5B receptor is the first example of a brain-specific protein that is absent in human. [PDF]

Grailhe R, Waeber C, Dulawa SC, Hornung JP, Zhuang X, Brunner D, Geyer MA, Hen R.
Increased exploratory activity and altered response to LSD in mice lacking the 5-HT(5A) receptor.
Neuron 1999 Mar;22(3):581-91
"In order to determine the distribution and function of the 5-HT5A serotonin receptor subtype, we generated knockout mice lacking the 5-HT5A gene. Comparative autoradiography studies of brains of wild-type (wt) and 5-HT5A knockout (5A-KO) mice revealed the existence of binding sites with high affinity for [125I]LSD that correspond to 5-HT5A receptors and that are concentrated in the olfactory bulb, neocortex, and medial habenula. When exposed to novel environments, the 5A-KO mice displayed increased exploratory activity but no change in anxiety-related behaviors. In addition, the stimulatory effect of LSD on exploratory activity was attenuated in 5A-KO mice. These results suggest that 5-HT5A receptors modulate the activity of neural circuits involved specifically in exploratory behavior and suggest that some of the psychotropic effects of LSD may be mediated by 5-HT5A receptors." [Abstract]

Pasqualetti M, Ori M, Nardi I, Castagna M, Cassano GB, Marazziti D.
Distribution of the 5-HT5A serotonin receptor mRNA in the human brain.
Brain Res Mol Brain Res 1998 May;56(1-2):1-8
"The 5-HT5A receptor is a member of a new subfamily of serotonin [5-hydroxytryptamine (5-HT)] receptors recently cloned from the human and rodent brain. The role of this receptor in normal brain functions as well as its possible involvement in pathological states is still to be determined. We therefore studied the regional distribution and cellular localization of 5-HT5A receptor mRNA in human brain sections from autopsy samples by in situ hybridization histochemistry, in order to obtain anatomical information which might be useful in formulating hypotheses on possible functions subserved by this receptor in the central nervous system (CNS). Our results showed that the main sites of 5-HT5A mRNA expression were the cerebral cortex, hippocampus and cerebellum. In the neocortical regions, the 5-HT5A receptor mRNA was mainly distributed in the layers II-III and V-VI. In the hippocampus, the dentate gyrus and the pyramidal cell layer of the CA1 and CA3 fields expressed 5-HT5A mRNA at high levels. The broad distribution in the neocortex and hippocampus supports the view that the 5-HT5A receptor in these areas might be implicated in high cortical and limbic functions. The 5-HT5A mRNA was widely distributed in the cerebellum where it was highly expressed in the Purkinje cells, in the dentate nucleus and, at a lower level, in the granule cells. Since the cerebellum receives diffuse serotonergic afferents, this finding suggests that the 5-HT5A receptor may have an important role in mediating the effects of 5-HT on cerebellar functions. Copyright 1998 Elsevier Science B.V." [Abstract]

Carson MJ, Thomas EA, Danielson PE, Sutcliffe JG.
The 5HT5A serotonin receptor is expressed predominantly by astrocytes in which it inhibits cAMP accumulation: a mechanism for neuronal suppression of reactive astrocytes.
Glia 1996 Aug;17(4):317-26
"The mRNA for the 5-hydroxytryptamine receptor 5-HT5A was detected at embryonic day 18 in the rat central nervous system and peaked by postnatal day 20. At all time points examined, 5-HT5A immunoreactivity observed on astrocyte cell bodies and in the stellate processes not only colocalized with the astrocyte-specific marker glial fibrillary acidic protein (GFAP) but was coordinately regulated with GFAP, increasing during development and during gliosis. Transfection of 5-HT5A into glioma cells prevented the 5-HT-induced increase in cAMP observed in untransfected cells and decreased the relative forskolin response by approximately 20%, suggesting that the 5-HT5A receptor couples negatively to adenylyl cyclase in astrocytes. Together, these results indicate a neuron-to-astrocyte serotonergic signaling pathway mediating cAMP concentrations, which could provide a neuronally driven mechanism for regulating astrocyte physiology with relevance to gliosis." [Abstract]

Wang ZY, Keith IM, Beckman MJ, Brownfield MS, Vidruk EH, Bisgard GE.
5-HT5a receptors in the carotid body chemoreception pathway of rat.
Neurosci Lett 2000 Jan 7;278(1-2):9-12
"By using a specific antibody, 5-HT5a receptor-like immunoreactivity was revealed in the chemoreceptive, oxygen sensitive, carotid body (CB) type I cells, and neurons of the petrosal ganglion (PG) and the superior cervical ganglion (SCG) in rat. mRNA encoding for the 5-HTa receptor was also detected in these tissues by RT-PCR, and confirmed with DNA sequencing. The present study provides direct evidence that 5-HT5a receptors are expressed in the CB, PG and SCG, which all likely play fundamental roles in arterial chemoreception." [Abstract]

MG Erlander, TW Lovenberg, BM Baron, L de Lecea, PE Danielson, M Racke, AL Slone, BW Siegel, PE Foye, K Cannon, JE Burns, and JG Sutcliffe
Two Members of a Distinct Subfamily of 5-Hydroxytryptamine Receptors Differentially Expressed in Rat Brain
PNAS 90: 3452-3456, 1993. [Abstract/Full Text]

Rees S, den Daas I, Foord S, Goodson S, Bull D, Kilpatrick G, Lee M.
Cloning and characterisation of the human 5-HT5A serotonin receptor.
FEBS Lett 1994 Dec 5;355(3):242-6
"The human 5-HT5A serotonin receptor has been cloned. As with the mouse and rat 5-HT5A receptors, the gene consists of two coding exons separated by a large intron. The deduced amino acid sequence of the gene reveals a protein of 357 residues which shares 93% (nucleotide) and 84% (amino acid) identity to the cloned mouse 5-HT5A receptor. We have determined the tissue distribution of the receptor by reverse transcriptase-PCR and found expression in all regions of the brain examined with little or no expression in peripheral tissues. The receptor has been transiently expressed in Cos M6 cells and exhibits a pharmacological profile closely resembling the mouse and rat 5-HT5A receptors with high, specific binding for ergotamine and methiothepin." [Abstract]

Dubertret C, Hanoun N, Ades J, Hamon M, Gorwood P.
Family-based association studies between 5-HT5A receptor gene and schizophrenia.
J Psychiatr Res. 2004 Jul-Aug;38(4):371-6.
"BACKGROUND: Pharmacological and neurodevelopmental data support the idea that the gene, which codes for the 5-HT(5A) receptor is an important candidate gene for schizophrenia susceptibility. However, previous genetic studies focusing on this gene yielded conflicting results, potentially because of: (i) stratification biases of case-control association studies, (ii) genetic and phenotypic heterogeneity of schizophrenia, and (iii) variability in the loci analyzed (the 5-HT(5A) gene having many polymorphic sites). METHODS: A transmission disequilibrium test was used in the present study aimed at investigating two polymorphisms in exon 1 of the 5-HT(5A) gene, the A12T silent substitution and the C43T transversion leading to a 15Pro --> Ser substitution, in 103 patients with DSM-IV diagnosis of schizophrenia, and their 206 parents. RESULTS: We found an excess of transmission of the 12T allele from the parents to their affected children (P = 0.02), with evidence for linkage disequilibrium between the 12T-43C haplotype and schizophrenia (P = 0.002). Furthermore, patients with the 12T allele had a significantly later age at onset (P = 0.003), and the Q-TDT approach confirmed that this allele was transmitted with an older age at onset (P = 0.01). CONCLUSIONS: These data provided convergent evidence for a significant role of the 5-HT(5A) gene in schizophrenia and more specifically in patients with later age at onset." [Abstract]

Birkett JT, Arranz MJ, Munro J, Osbourn S, Kerwin RW, Collier DA.
Association analysis of the 5-HT5A gene in depression, psychosis and antipsychotic response.
Neuroreport. 2000 Jun 26;11(9):2017-20.
"The serotonergic system is targeted by both antidepressants and atypical antipsychotic drugs such as clozapine. Genetic variation in the 5-HT5A gene might be involved in susceptibility to depression, the major psychoses or in influencing clinical response to treatment. To examine this hypothesis we genotyped two polymorphisms (-19G/C; 12A/T) in the human 5-HT5A receptor gene in a sample of 269 unrelated schizophrenic patients treated with clozapine, 112 bipolar patients, 75 unipolar patients and 187 controls. After five-fold correction for multiple testing, allelic association was found with the -19G/C polymorphism and bipolar affective disorder, (p = 0.025; OR 0.56), unipolar depression (p = 0.004; OR 0.52) and schizophrenia (p = 0.036; OR 0.67) indicating a potential protective effect of the G19 allele. For the 12A/T polymorphism allelic association was observed with unipolar depression only (p = 0.004). We conclude that allelic variation in the human 5-HT5A receptor gene may be involved in susceptibility to schizophrenia and affective disorders but not in determining response to clozapine." [Abstract]

Arias B, Collier DA, Gasto C, Pintor L, Gutierrez B, Valles V, Fananas L.
Genetic variation in the 5-HT5A receptor gene in patients with bipolar disorder and major depression.
Neurosci Lett 2001 May 4;303(2):111-4
"Our results suggest that the polymorphisms analyzed in the 5-HT5A receptor gene do not play a major role in the pathogenesis of affective disorders." [Abstract]

Shimron-Abarbanell D, Erdmann J, Vogt IR, Bryant SP, Spurr NK, Knapp M, Propping P, Nothen MM.
Human 5-HT5A receptor gene: systematic screening for DNA sequence variation and linkage mapping on chromosome 7q34-q36 using a polymorphism in the 5' untranslated region.
Biochem Biophys Res Commun 1997 Apr 7;233(1):6-9
"Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter that mediates a wide range of sensory, motor, and cortical functions by activating multiple 5-HT receptor subtypes. In the present study we performed a systematic mutation scan of the complete coding region of the 5-HT5A receptor to explore its variability in the general population. Investigating 46 unrelated healthy subjects by single-strand conformation analysis no sequence changes of likely functional relevance were observed. The detection of a frequent G-->C substitution at position -19 was used for fine scale linkage mapping of the 5-HT5A gene. Employing a polymerase-chain-reaction based assay we genotyped 7 CEPH families (Centre d'Etude du Polymorphisme Humaine) and mapped the receptor to genetic markers on chromosome 7q34-q36." [Abstract]

Francken, Bart J. B., Josson, Katty, Lijnen, Peter, Jurzak, Mirek, Luyten, Walter H. M. L., Leysen, Josee E.
Human 5-Hydroxytryptamine5A Receptors Activate Coexpressed Gi and Go Proteins in Spodoptera frugiperda 9 Cells
Mol Pharmacol 2000 57: 1034-1044
"In summary, the h5-HT5A receptor selectively coupled to mammalian Gi1/Gi2/Gi3 and Go but not to Gz/Gs/Gq/11/16 or G12/13 proteins, when coexpressed in Sf9 insect cells. Although Go displayed different receptor coupling characteristics than Gi proteins, no clear coupling preference was evident." [Full Text]
Francken BJ, Jurzak M, Vanhauwe JF, Luyten WH, Leysen JE.
The human 5-ht5A receptor couples to Gi/Go proteins and inhibits adenylate cyclase in HEK 293 cells.
Eur J Pharmacol 1998 Nov 20;361(2-3):299-309 [Abstract]
Hurley, PT, McMahon, RA, Fanning, P, O'Boyle, KM, Rogers, M, Martin, F
Functional coupling of a recombinant human 5-HT5A receptor to G- proteins in HEK-293 cells
Br. J. Pharmacol. 1998 124: 1238-1244 [Abstract/Full Text]
Noda M, Yasuda S, Okada M, Higashida H, Shimada A, Iwata N, Ozaki N, Nishikawa K, Shirasawa S, Uchida M, Aoki S, Wada K.
Recombinant human serotonin 5A receptors stably expressed in C6 glioma cells couple to multiple signal transduction pathways.
J Neurochem. 2003 Jan;84(2):222-32.
"Human serotonin 5A (5-HT5A) receptors were stably expressed in undifferentiated C6 glioma. In 5-HT5A receptors-expressing cells, accumulation of cAMP by forskolin was inhibited by 5-HT as reported previously. Pertussis toxin-sensitive inhibition of ADP-ribosyl cyclase was also observed, indicating a decrease of cyclic ADP ribose, a potential intracellular second messenger mediating ryanodine-sensitive Ca2+ mobilization. On the other hand, 5-HT-induced outward currents were observed using the patch-clamp technique in whole-cell configuration. The 5-HT-induced outward current was observed in 84% of the patched 5-HT5A receptor-expressing cells and was concentration-dependent. The 5-HT-induced current was inhibited when intracellular K+ was replaced with Cs+ but was not significantly inhibited by typical K+ channel blockers. The 5-HT-induced current was significantly attenuated by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) in the patch pipette. Depleting intracellular Ca2+ stores by application of caffeine or thapsigargin also blocked the 5-HT-induced current. Blocking G protein, the inositol triphosphate (IP3) receptor, or pretreatment with pertussis toxin, all inhibited the 5-HT-induced current. IP3 showed a transient increase after application of 5-HT in 5-HT5A receptor-expressing cells. It was concluded that in addition to the inhibition of cAMP accumulation and ADP-ribosyl cyclase activity, 5-HT5A receptors regulate intracellular Ca2+ mobilization which is probably a result of the IP3-sensitive Ca2+ store. These multiple signal transduction systems may induce complex changes in the serotonergic system in brain function." [Abstract]
Thomas DR, Larminie CG, Lyons HR, Fosberry A, Hill MJ, Hayes PD.
Cloning and pharmacological characterisation of the guinea pig 5-ht5A receptor.
Eur J Pharmacol. 2004 Jun 28;494(2-3):91-9.
"The guinea pig 5-hydroxytryptamine(5A) (gp5-ht(5A)) receptor was cloned from guinea pig brain using degenerate polymerase chain reaction (PCR) and shows 88%, 85% and 84% amino acid sequence identity versus the human, rat and mouse 5-ht(5A) receptors, respectively. The receptor was transiently expressed in human embryonic kidney (HEK) 293 cells. [(3)H]-Lysergic acid diethylamide (LSD) bound saturably to gp5-ht(5A)/HEK293 membranes with a K(d) of 2.3+/-0.1 nM and B(max) of 15.7+/-3.4 pmol/mg protein. The receptor binding profile, determined by competition with [(3)H]LSD, correlated well with that for the human 5-ht(5A) receptor. 5-HT stimulated [(35)S]GTPgammaS binding to gp5-ht(5A)/HEK293 membranes (pEC(50) 8.1+/-0.2), and the response was surmountably antagonised by methiothepin and ritanserin, giving apparent pK(B) values of 8.0 and 7.2, respectively. The 5-HT response was absent using membranes prepared from gp5-ht(5A)/HEK293 cells pretreated with pertussis toxin (PTX). These data suggest that the gp5-ht(5A) receptor couples to G(i)-proteins in this expression system and shows a similar pharmacological profile to that for the human 5-ht(5A) receptor." [Abstract]

Geurts FJ, De Schutter E, Timmermans JP.
Localization of 5-HT2A, 5-HT3, 5-HT5A and 5-HT7 receptor-like immunoreactivity in the rat cerebellum.
J Chem Neuroanat 2002 Jun;24(1):65-74
"Although serotonin (5-hydroxytryptamine, 5-HT) is known to exert a modulatory action on cerebellar function, our current knowledge of the nature of receptor subtypes mediating serotonergic activity in this part of the brain remains fragmentary. In this study, we report the presence and distribution of 5-HT3, 5-HT5A and 5-HT7 receptor-like immunoreactivity in the rat cerebellum using immunofluorescence histochemistry. 5-HT3 immunoreactivity was found in fibers sparsely distributed throughout the cerebellum. Most of them were seen in the cerebellar cortex as fine varicose 5-HT3-positive axonal processes. 5-HT5A immunoreactivity, on the other hand, was observed in neuronal somata of the cerebellar cortex and deep cerebellar nuclei. Based upon cell morphology and the use of cell-specific markers, Purkinje cells, molecular layer interneurons and Golgi cells were found to be 5-HT5A immunopositive." [Abstract]
Waeber C, Grailhe R, Yu XJ, Hen R, Moskowitz MA.
Putative 5-ht5 receptors: localization in the mouse CNS and lack of effect in the inhibition of dural protein extravasation.
Ann N Y Acad Sci 1998 Dec 15;861:85-90
"Putative 5-ht5 receptor binding sites were visualized by in vitro autoradiography using [125I]LSD (in the presence of clozapine and spiperone) or [3H]5-carboxamidotryptamine (in the presence 8-OH-DPAT, GR127935 and spiperone). Under these conditions, no [3H]5-carboxamidotryptamine labeling was detected in the brain of mice lacking the gene encoding the putative 5-ht5a receptor (knockout mice), whereas intermediate densities of binding sites were seen in the olfactory bulb and neocortex of wild-type mice. [125I]LSD labeled the same areas as [3H]5-carboxamidotryptamine in wild-type mice. High densities of [125I]LSD binding sites were observed in the medial habenula of wild type and knockout mice. 5-CT competed for [125I]LSD binding sites with an affinity of 2 nM in the olfactory bulb and neocortex of wild-type mice and an affinity of 30 nM in the habenula of knockout mice, suggesting that habenular labeling might be accounted for by putative 5-ht5b receptors. In the presence of 5'-guanylylimidodiphosphate, 5-CT displaced [125I]LSD from putative 5-ht5a and 5-ht5b sites with a 6-times and 3-times lower affinity, respectively, suggesting that both receptor subtypes are coupled to G proteins in brain. We also studied the inhibitory effect of 5-CT on dural neurogenic inflammation in knockout mice. In wild type mice, 3 ng/kg 5-CT inhibited dural protein extravasation by 60%. A similar effect was observed in knockout mice, even in the presence of the 5-HT1B receptor antagonist GR127935. These results suggest that the inhibitory effects of 5-CT are not mediated by a site with the characteristics of the putative 5-ht5 receptor." [Abstract]
Ramage AG.
Identification of one of the least well understood 5-HT receptors (5-ht(5A)) in the spinal cord.
J Comp Neurol. 2004 Aug 30;476(4):313-315. [Abstract]
McLean DL, Sillar KT.
Divergent actions of serotonin receptor activation during fictive swimming in frog embryos.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2004 May;190(5):391-402. Epub 2004 Feb 26.
"We have investigated the pharmacology underlying locomotor system responses to serotonin (5-HT) in embryos of the frog, Rana temporaria, to provide a comparison to studies in embryos of its close relative, Xenopus laevis. Our findings suggest that two divergent mechanisms underlie the modulation of locomotion by 5-HT in Rana. Bath-applied 5-HT or 5-carboxamidotyptamine, a 5-HT(1,5A,7) receptor agonist, can modulate fictive swimming in a dose-dependent manner, increasing burst durations and cycle periods. However, activation of 5-HT(1,7) receptors with R8-OHDPAT or 8-OHDPAT fails to mimic 5-HT, and in some cases exerts exactly the opposite response; decreasing burst durations and cycle periods. Elevating endogenous 5-HT levels by blocking re-uptake with clomipramine transiently increases burst durations. The receptors involved in this endogenous response include 5-HT(1A) receptors, as in Xenopus, but also 5-HT(7) receptors. However, like the 8-OHDPAT enantiomers, prolonged re-uptake inhibition can result in a motor response in the opposite direction to exogenous 5-HT. This effect is not reversed by 5-HT(1A) and/or 5-HT(7) receptor antagonism, implicating 5-HT(1B/1D) receptors. Remarkably, antagonism of these receptors using methiothepin unmasks a dose-dependent response to clomipramine, reminiscent of exogenous 5-HT. Our data suggest that 5-HT(1A,7) and 5-HT(1B/1D) receptors act as gain-setters of burst durations, whilst 5-HT(5A) receptors are involved in the effects of bath-applied 5-HT on locomotion." [Abstract]
Wisden W, Parker EM, Mahle CD, Grisel DA, Nowak HP, Yocca FD, Felder CC, Seeburg PH, Voigt MM.
Cloning and characterization of the rat 5-HT5B receptor. Evidence that the 5-HT5B receptor couples to a G protein in mammalian cell membranes.
FEBS Lett 1993 Oct 25;333(1-2):25-31
"A gene encoding a novel G protein-coupled 5-hydroxytryptamine (5-HT) receptor, termed 5-HT5B, was cloned. The ligand binding profile of this receptor is distinct from that of other cloned 5-HT receptors. The 5-HT5B receptor couples to a G protein in COS1 cell membranes; however, activation of the 5-HT5B receptor does not appear to alter either cAMP accumulation or phosphoinositide turnover in a variety of fibroblast cell lines. In the rat brain, 5-HT5B gene expression occurs predominantly in the medial habenulae and hippocampal CA1 cells of the adult. Little expression is seen during embryonic development." [Abstract]

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Recent 5-HT5 Receptor Research
1) Harlos M, Ott I, Gust R, Alborzinia H, Wölfl S, Kromm A, Sheldrick WS
Synthesis, Biological Activity, and Structure-Activity Relationships for Potent Cytotoxic Rhodium(III) Polypyridyl Complexes.
J Med Chem. 2008 Jun 11;
The complexes mer-[RhCl 3(DMSO-kappa S)(pp)] 1a- 5a may be prepared by reaction of mer,cis-[RhCl 3(DMSO-kappa S) 2(DMSO-kappa O)] with the appropriate polypyridyl ligand (pp = bpy, phen, dpq, dppz, dppn) in CH 3OH/H 2O solution at 75 degrees C. The mer isomers of 1a- 5a are stable in chloroform solution but those of 1a and 2a isomerize rapidly to a mixture of fac and mer isomers in DMSO. The complexes are potent in vitro cytotoxic agents and exhibit IC 50 values that are strongly dependent on the size of the polypyridyl ligand. IC 50 values of, respectively, 4.0 (0.5) and 1.9 (0.5), 0.40 (0.06) and 0.19 (0.05), and 0.079 (0.012) and 0.069 (0.021) microM are observed for 1a- 3a against the human cell lines MCF-7 (breast cancer) and HT-29 (colon cancer). Cellular uptake studies showed a rapid and high accumulation of the polypyridyl compounds. Treatment of HT-29 and MCF-7 cells with 3a leads to significant decreases in cellular oxygen consumption and the rate of extracellular acidification. [PubMed Citation] [Order full text from Infotrieve]

2) Scharwitz MA, Ott I, Gust R, Kromm A, Sheldrick WS
Synthesis, cellular uptake and structure-activity relationships for potent cytotoxic trichloridoiridium(III) polypyridyl complexes.
J Inorg Biochem. 2008 Mar 28;
The complexes fac-[IrCl(3)(DMSO)(pp)] 1a-5a may be prepared by stepwise reaction of IrCl(3).3H(2)O with the appropriate polypyridyl ligand (pp=bpy, phen, dpq, dppz, dppn) and DMSO in CH(3)OH solution in the dark. The fac isomers of 1a-5a are stable in light-protected CD(2)Cl(2) solution but, with the exception of 5a, isomerize rapidly to a mixture of the fac and mer isomers in the presence of light. In contrast, solutions of the fac isomers in the polar solvents D(2)O and CD(3)OD are stable under such conditions. The isomer mer-[IrCl(3)(DMSO-kappaS)(phen)] 2b was, however, isolated by slow evaporation of an H(2)O/CH(3)OH solution of 2a and characterized by X-ray structural analysis. UV/Vis and CD studies of the interaction of 1a-5a with calf thymus DNA are in accordance with an effective absence of intercalation. (1)H NMR studies indicate that the complexes react slowly with compounds containing soft S donor atoms (e. g. N-acetylmethionine) but do not react with the guanine base of 5'-GMP(2-). The complexes 2a-5a are potent in vitro cytotoxic agents toward the human cell lines MCF-7 and HT-29 and their IC(50) values are dependent on the size of the polypyridyl ligand in the order phen, dpq>dppz>dppn. For instance IC(50) values of 5.5 (0.9), 0.8 (0.3) and 0.21 (0.11)muM were established for 3a-5a against MCF-7 cells and 6.1 (0.7), 1.5 (0.2) and 1.3 (0.4)muM against HT-29 cells. These values correlate with the cellular uptake efficiency which, on exposure to 10muM solutions, reaches its highest levels (19.3(0.8) and 37.4(8.9) ng Ir/mg protein for MCF-7 and HT-29, respectively) for the dppn compound 5a. [PubMed Citation] [Order full text from Infotrieve]

3) Schultz DM, Prescher JA, Kidd S, Marona-Lewicka D, Nichols DE, Monte A
'Hybrid' benzofuran-benzopyran congeners as rigid analogs of hallucinogenic phenethylamines.
Bioorg Med Chem. 2008 Jun 1;16(11):6242-51.
Phenylalkylamines that possess conformationally rigidified furanyl moieties in place of alkoxy arene ring substituents have been shown previously to possess the highest affinities and agonist functional potencies at the serotonin 5-HT(2A) receptor among this chemical class. Further, affinity declines when both furanyl rings are expanded to the larger dipyranyl ring system. The present paper reports the synthesis and pharmacological evaluation of a series of 'hybrid' benzofuranyl-benzopyranyl phenylalkylamines to probe further the sizes of the binding pockets within the serotonin 5-HT(2A) agonist binding site. Thus, 4(a-b), 5(a-b), and 6 were prepared as homologs of the parent compound, 8-bromo-1-(2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran-4-yl)-2-aminopropane 2, and their affinity, functional potency, and intrinsic activity were assessed using cells stably expressing the rat 5-HT(2A) receptor. The behavioral pharmacology of these new analogs was also evaluated in the two-lever drug discrimination paradigm. Although all of the hybrid isomers had similar, nanomolar range receptor affinities, those with the smaller furanyl ring at the arene 2-position (4a-b) displayed a 4- to 15-fold greater functional potency than those with the larger pyranyl ring at that position (5a-b). When the furan ring of the more potent agonist 4b was aromatized to give 6, a receptor affinity similar to the parent difuranyl compound 2 was attained, along with a functional potency equivalent to 2, 4a, and 4b. In drug discrimination experiments using rats trained to discriminate LSD from saline, 4b was more than two times more potent than 5b, with the latter having a potency similar to the classic hallucinogenic amphetamine 1 (DOB). [PubMed Citation] [Order full text from Infotrieve]

4) Fish PV, Deur C, Gan X, Greene K, Hoople D, Mackenny M, Para KS, Reeves K, Ryckmans T, Stiff C, Stobie A, Wakenhut F, Whitlock GA
Design and synthesis of morpholine derivatives. SAR for dual serotonin & noradrenaline reuptake inhibition.
Bioorg Med Chem Lett. 2008 Apr 15;18(8):2562-6.
Single enantiomer (SS) and (RR) 2-[(phenoxy)(phenyl)methyl]morpholine derivatives 5, 8-23 are inhibitors of monoamine reuptake. Target compounds were prepared using an enantioselective synthesis employing a highly specific enzyme-catalysed resolution of racemic n-butyl 4-benzylmorpholine-2-carboxylate (26) as the key step. Structure-activity relationships established that serotonin and noradrenaline reuptake inhibition are functions of stereochemistry and aryl/aryloxy ring substitution. Consequently, selective SRI, selective NRI and dual SNRIs were all identified. One of these compounds, a potent and selective dual SNRI, (SS)-5a was selected as a candidate for further pre-clinical evaluation. [PubMed Citation] [Order full text from Infotrieve]

5) Lindemann MJ, Hu Z, Benczik M, Liu KD, Gaffen SL
Differential regulation of the IL-17 receptor by gammac cytokines: inhibitory signaling by the phosphatidylinositol 3-kinase pathway.
J Biol Chem. 2008 May 16;283(20):14100-8.
The gammac-family cytokine IL-2 activates signaling events that contribute to cell survival and proliferation, the best-studied of which are the STAT-5 and phosphatidylinositol 3-kinase (PI3K) pathways. The starting point of this study was to define genes regulated by the IL-2R-mediated PI3K pathway in T cells. Accordingly, we used an erythropoietin (EPO) receptor chimeric receptor system in which IL-2-dependent HT-2 T cells expressed a mutant EPO-IL-2Rbeta construct where Tyr-338 is mutated to Phe. Cells expressing this mutant IL-2Rbeta chain fail to induce phosphorylation of PI3K-p85alpha/beta or activate Akt, but mediate normal IL-2-dependent proliferation and activation of JAK1 and STAT-5A/B. Microarray analyses revealed differential regulation of numerous genes compared with cells expressing a wild-type IL-2Rbeta, including up-regulation of the IL-17 receptor subunit IL-17RA. Blockade of the PI3K pathway but not p70S6K led to up-regulation of IL-17RA, and constitutive Akt activation was associated with suppressed IL-17RA expression. Moreover, similar to the mutant EPO-IL-2Rbeta chimera, IL-15 and IL-21 induced IL-17RA preferentially compared with IL-2, and IL-2 but not IL-15 or IL-21 mediated prolonged activation of the PI3K p85 regulatory subunit. Thus, there are intrinsic signaling differences between IL-2 and IL-15 that can be attributed to differences in activation of the PI3K pathway. [PubMed Citation] [Order full text from Infotrieve]

6) Thomsen WJ, Grottick AJ, Menzaghi F, Reyes-Saldana H, Espitia S, Yuskin D, Whelan K, Martin M, Morgan M, Chen W, Al-Shamma H, Smith B, Chalmers D, Behan D
Lorcaserin, a novel selective human 5-hydroxytryptamine2C agonist: in vitro and in vivo pharmacological characterization.
J Pharmacol Exp Ther. 2008 May;325(2):577-87.
5-Hydroxytryptamine (5-HT)(2C) receptor agonists hold promise for the treatment of obesity. In this study, we describe the in vitro and in vivo characteristics of lorcaserin [(1R)-8-chloro-2,3,4,5-tetrahydro-1-methyl-1H-3 benzazepine], a selective, high affinity 5-HT(2C) full agonist. Lorcaserin bound to human and rat 5-HT(2C) receptors with high affinity (K(i) = 15 +/- 1 nM, 29 +/- 7 nM, respectively), and it was a full agonist for the human 5-HT(2C) receptor in a functional inositol phosphate accumulation assay, with 18- and 104-fold selectivity over 5-HT(2A) and 5-HT(2B) receptors, respectively. Lorcaserin was also highly selective for human 5-HT(2C) over other human 5-HT receptors (5-HT(1A), 5-HT(3), 5-HT(4C), 5-HT5(5A), 5-HT(6), and 5-HT(7)), in addition to a panel of 67 other G protein-coupled receptors and ion channels. Lorcaserin did not compete for binding of ligands to serotonin, dopamine, and norepinephrine transporters, and it did not alter their function in vitro. Behavioral observations indicated that unlike the 5-HT(2A) agonist (+/-)-1-(2,5-dimethoxy-4-phenyl)-2-aminopropane, lorcaserin did not induce behavioral changes indicative of functional 5-HT(2A) agonist activity. Acutely, lorcaserin reduced food intake in rats, an effect that was reversed by pretreatment with the 5-HT(2C)-selective antagonist 6-chloro-5-methyl-1-[6-(2-methylpyridin-3-yloxy)pyridin-3-yl-carbamoyl]indoline (SB242,084) but not the 5-HT(2A) antagonist (R)-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine-methanol (MDL 100,907), demonstrating mediation by the 5-HT(2C) receptor. Chronic daily treatment with lorcaserin to rats maintained on a high fat diet produced dose-dependent reductions in food intake and body weight gain that were maintained during the 4-week study. Upon discontinuation, body weight returned to control levels. These data demonstrate lorcaserin to be a potent, selective, and efficacious agonist of the 5-HT(2C) receptor, with potential for the treatment of obesity. [PubMed Citation] [Order full text from Infotrieve]

7) Mysliwiec J, Zbucki R, Winnicka M, Sawicki B, Nikolajuk A, Kaminski K, Mysliwiec P, Musial W, Bondyra Z, Walecki J, Gorska M
Interleukin-6 is not essential for bone turnover in hypothyroid mice.
Folia Histochem Cytobiol. 2007;45(4):387-92.
Interleukin-6 (IL-6) has been shown to be involved in the pathogenesis of several bone diseases characterized by an imbalance between bone resorption and formation. The aim of the study was to estimate serum markers of bone turnover: osteoclast-derived tartrate-resistant acid phosphatase form 5a (TRACP 5b) and osteocalcin in IL-6-deficient mice to assess the role of IL-6 in bone metabolism in hypothyroidism in mice. C57BL/6J (wild-type; WT) and C57BL/6J(IL6-/-Kopf) (IL-6 knock-out; IL6KO) mice randomly divided into 4 groups with 10 in each one: 1/ WT mice in hypothyroidism (WT-ht), 2/ WT controls, 3/ IL6KO mice with hypothyroidism (IL6KO-ht) and 4/ IL6KO controls. Experimental model of hypothyroidism was induced by intraperitoneal injection of propylthiouracyl. The serum levels of TRACP 5b and osteocalcin were determined by ELISA. Serum concentrations of TRACP 5b (median and interquartile ranges) were significantly decreased in both groups of mice with hypothyroidism: WT (3.2 (2.5-4.7) U/l) and IL6KO (2.6 (1.8-3.5) U/l) as compared to the respective controls. Similarly, serum osteocalcin levels were significantly reduced in both groups of mice in experimental hypothyroidism: WT (25.8 (23.0-28.2) ng/ml) and IL6KO (21.5(19.0-24.6) ng/ml) in comparison to the respective controls. There were no significant differences in bone turnover markers between IL6KO and WT mice both in hypothyroid and control animals. The results of the present study suggest that IL-6 does not play an important role in bone turnover in both euthyroid and hypothyroid mice. [PDF] [Free Full Text] [PubMed Citation] [Order full text from Infotrieve]

8) Dutton AC, Massoura AN, Dover TJ, Andrews NA, Barnes NM
Identification and functional significance of N-glycosylation of the 5-ht5A receptor.
Neurochem Int. 2008 Feb;52(3):419-25.
The presence and roles of N-glycosylation of the human (h) 5-ht(5A) receptor were investigated using a heterologous expression system. Following transient transfection of COS-7 cells with h5-ht(5A) receptor cDNA, SDS-PAGE/Western blot analysis of immunoreactivity demonstrated two protein species; a predominant species with a molecular weight of approximately 35-45 kDa and a minor species of approximately 45-55 kDa. Transfected cells grown in the presence of the N-glycosylation inhibitor tunicamycin, failed to express the minor immunoreactive species indicating this represented the N-glycosylated form of the h5-ht(5A) receptor. Comparison of the molecular weights of immunoreactive bands arising from the wild-type and each of the mutant 5-ht(5A) receptors with disruption of the predicted N-glycosylation sites (N6S and N21S) demonstrated that both identified asparagines were N-glycosylated. Immunocytochemical and ELISA studies demonstrated that the [N6S]h5-ht(5A) receptor mutation, but not the [N21S]h5-ht(5A) receptor mutation, reduced protein expression in the cell membrane, indicating that N-glycosylation of the N6 residue is important for the membrane expression of this neurotransmitter receptor; a requirement for receptor function. [PubMed Citation] [Order full text from Infotrieve]

9) Villal�n CM, Centuri�n D
Cardiovascular responses produced by 5-hydroxytriptamine:a pharmacological update on the receptors/mechanisms involved and therapeutic implications.
Naunyn Schmiedebergs Arch Pharmacol. 2007 Oct;376(1-2):45-63.
The complexity of cardiovascular responses produced by 5-hydroxytryptamine (5-HT, serotonin), including bradycardia or tachycardia, hypotension or hypertension, and vasodilatation or vasoconstriction, has been explained by the capability of this monoamine to interact with different receptors in the central nervous system (CNS), on the autonomic ganglia and postganglionic nerve endings, on vascular smooth muscle and endothelium, and on the cardiac tissue. Depending, among other factors, on the species, the vascular bed under study, and the experimental conditions, these responses are mainly mediated by 5-HT(1), 5-HT(2), 5-HT(3), 5-HT(4), 5-ht(5A/5B), and 5-HT(7) receptors as well as by a tyramine-like action or unidentified mechanisms. It is noteworthy that 5-HT(6) receptors do not seem to be involved in the cardiovascular responses to 5-HT. Regarding heart rate, intravenous (i.v.) administration of 5-HT usually lowers this variable by eliciting a von Bezold-Jarisch-like reflex via 5-HT(3) receptors located on sensory vagal nerve endings in the heart. Other bradycardic mechanisms include cardiac sympatho-inhibition by prejunctional 5-HT(1B/1D) receptors and, in the case of the rat, an additional 5-ht(5A/5B) receptor component. Moreover, i.v. 5-HT can increase heart rate in different species (after vagotomy) by a variety of mechanisms/receptors including activation of: (1) myocardial 5-HT(2A) (rat), 5-HT(3) (dog), 5-HT(4) (pig, human), and 5-HT(7) (cat) receptors; (2) adrenomedullary 5-HT(2) (dog) and prejunctional sympatho-excitatory 5-HT(3) (rabbit) receptors associated with a release of catecholamines; (3) a tyramine-like action mechanism (guinea pig); and (4) unidentified mechanisms (certain lamellibranch and gastropod species). Furthermore, central administration of 5-HT can cause, in general, bradycardia and/or tachycardia mediated by activation of, respectively, 5-HT(1A) and 5-HT(2) receptors. On the other hand, the blood pressure response to i.v. administration of 5-HT is usually triphasic and consists of an initial short-lasting vasodepressor response due to a reflex bradycardia (mediated by 5-HT(3) receptors located on vagal afferents, via the von Bezold-Jarisch-like reflex), a middle vasopressor phase, and a late, longer-lasting, vasodepressor response. The vasopressor response is a consequence of vasoconstriction mainly mediated by 5-HT(2A) receptors; however, vasoconstriction in the canine saphenous vein and external carotid bed as well as in the porcine cephalic arteries and arteriovenous anastomoses is due to activation of 5-HT(1B) receptors. The late vasodepressor response may involve three different mechanisms: (1) direct vasorelaxation by activation of 5-HT(7) receptors located on vascular smooth muscle; (2) inhibition of the vasopressor sympathetic outflow by sympatho-inhibitory 5-HT(1A/1B/1D) receptors; and (3) release of endothelium-derived relaxing factor (nitric oxide) by 5-HT(2B) and/or 5-HT(1B/1D) receptors. Furthermore, central administration of 5-HT can cause both hypotension (mainly mediated by 5-HT(1A) receptors) and hypertension (mainly mediated by 5-HT(2) receptors). The increasing availability of new compounds with high affinity and selectivity for the different 5-HT receptor subtypes makes it possible to develop drugs with potential therapeutic usefulness in the treatment of some cardiovascular illnesses including hypertension, migraine, some peripheral vascular diseases, and heart failure. [PubMed Citation] [Order full text from Infotrieve]

10) Rua�o G, Thompson PD, Windemuth A, Seip RL, Dande A, Sorokin A, Kocherla M, Smith A, Holford TR, Wu AH
Physiogenomic association of statin-related myalgia to serotonin receptors.
Muscle Nerve. 2007 Sep;36(3):329-35.
We employed physiogenomic analyses to investigate the relationship between myalgia and selected polymorphisms in serotonergic genes, based on their involvement with pain perception and transduction of nociceptive stimuli. We screened 195 hypercholesterolemic, statin-treated patients, all of whom received either atorvastatin, simvastatin, or pravastatin. Patients were classified as having no myalgia, probable myalgia, or definite myalgia, and assigned a myalgia score of 0, 0.5, or 1, respectively. Fourteen single nucleotide polymorphisms (SNPs) were selected from candidates within the 5-HT receptor gene families [5a-hydroxytryptamine receptor genes (HTR) 1D, 2A, 2C, 3A, 3B, 5A, 6, 7] and the serotonin transporter gene (SLC6A4). SNPs in the HTR3B and HTR7 genes, rs2276307 and rs1935349, respectively, were significantly associated with the myalgia score. Individual differences in pain perception and nociception related to specific serotonergic gene variants may affect the development of myalgia in statin-treated patients. [PubMed Citation] [Order full text from Infotrieve]

11) Papageorgiou A, Denef C
Stimulation of growth hormone release by 5-hydroxytryptamine (5-HT) in cultured rat anterior pituitary cell aggregates: evidence for mediation by 5-HT2B, 5-HT7, 5-HT1B, and ketanserin-sensitive receptors.
Endocrinology. 2007 Sep;148(9):4509-22.
5-Hydroxytryptamine (5-HT) promotes the release of GH by a hypothalamic site of action. The present study explores a putative pituitary action in a perifused rat anterior pituitary aggregate cell culture system. In aggregates cultured with 1 nM estradiol for expression of the 5-HT4, -5, and -6 receptor (R), 5-HT promptly stimulated GH secretion with a dose dependency between 1 and 10 nM. The effect of 5-HT was partially blocked by methiothepin and methysergide; by SB-206553, a 5-HTR2B/C antagonist; SB-269970, a 5-HTR7/5A antagonist; and SB-224289, a 5-HTR1B antagonist. The GH response was fully blocked by combined administration of SB-206553+SB-269970 and SB-206553+ketanserin but not by SB-206553+spiperone. Culturing the aggregates without estradiol diminished the magnitude of the GH response to 5-HT as well as the impact of 5-HTR7/5 blockade on the response. Basal GH release was stimulated by the 5-HTR2 agonists 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane, m-chlorophenyl piperazine, and alpha-methyl 5-HT; 5-carboxytryptamine (agonist at 5-HTR1, -5, and -7); tryptamine (preferential 5-HTR7 agonist); and the selective 5-HTR1B agonist CP93129 but not the 5-HTR1A agonists 7-(dipropylamino)tetralin-1-ol-8-hydroxy-2-(di-n-propylamino)tetralin and the 5-HTR1B/D agonist sumatriptan. The selective 5-HTR2B agonist BW 723C86 stimulated GH release, and the selective 5-HTR2B antagonist SB-204741 attenuated the GH response to 5-HT. The present data suggest that 5-HT may release GH through a pituitary site of action, and that the 5-HTR2B, 5-HTR7 and 5-HTR1B mediate this response, with possibly an inhibitory component of the 5-HTR1D. The relative contribution of these receptors may be modulated by estrogen. [PubMed Citation] [Order full text from Infotrieve]

12) Prezzavento O, Campisi A, Ronsisvalle S, Li Volti G, Marrazzo A, Bramanti V, Cannav� G, Vanella L, Cagnotto A, Mennini T, Ientile R, Ronsisvalle G
Novel sigma receptor ligands: synthesis and biological profile.
J Med Chem. 2007 Mar 8;50(5):951-61.
The aim of the present study was to investigate the biological profile of new substituted 1-phenyl-2-cyclopropylmethylamines. High affinity for both sigma subtypes was achieved when 4-phenylpiperidin-4-ol (4a-e) and 4-benzylpiperidine moieties were present (5a-e). (1R,2S/1S,2R)-2-[4-Hydroxy-4-phenylpiperidin-1-yl)methyl]-1-(4-methylphenyl)cyclopropanecarboxylate (4b) showed high affinity for the sigma1 sites (Ki = 1.5 nM) and the most favorable sigma1/sigma2 selectivity (Ki(sigma2)/Ki(sigma1) = 33.9). Binding affinity studies showed that 4b binding on N-methyl-d-aspartate (NMDA), dopaminergic (D1, D2, D3), muscarinic, histaminergic H1, adrenergic (alpha1, alpha2), serotoninergic (5-HT2A, 5-HT2C, 5-HT3, 5-HT4, 5-HT6), DA (DAT), and 5-HT (SERT) transporters was not significant. Interestingly, sigma ligands differently induced the expression of tissue transglutaminase (TG-2) in primary astroglial cell cultures. We suggest that 4b may act as a sigma1/sigma2 agonist and that the sigma ligands may modulate TG-2 differently. [PubMed Citation] [Order full text from Infotrieve]

13) Cesari N, Biancalani C, Vergelli C, Dal Piaz V, Graziano A, Biagini P, Ghelardini C, Galeotti N, Giovannoni MP
Arylpiperazinylalkylpyridazinones and analogues as potent and orally active antinociceptive agents: synthesis and studies on mechanism of action.
J Med Chem. 2006 Dec 28;49(26):7826-35.
A number of arylpiperazinylalkylpyridazinones structurally related to the previously described lead A (5-{[4-(3-chlorophenyl)piperazin-1-yl]-propyl}-3-methyl-7-phenylisossazolo[4,5-d]pyridazin-4-(5H)-one) were synthesized and tested for their analgesic activity. Many of the tested molecules, at the dose of 20 mg kg-1 p.o., showed high antinociceptive activity, in particular, compounds 5a, 11c, 15a, 21 and 22, which were able to reduce the number of abdominal constrictions by more than 50% in writhing test. The pharmacological investigation of lead A led us to clarify the mechanism of action of this compound, showing that it carries out its analgesic action through the inhibition of reuptake of noradrenaline. The antinociception of some of the most interesting new molecules was completely prevented by pretreatment with alpha2-antagonist yohimbine, suggesting the involvement of alpha2-adrenoceptors, as with prototype A. [PubMed Citation] [Order full text from Infotrieve]

14) Canaparo R, Serpe L, Catalano MG, Bosco O, Zara GP, Berta L, Frairia R
High energy shock waves (HESW) for sonodynamic therapy: effects on HT-29 human colon cancer cells.
Anticancer Res. 2006 Sep-Oct;26(5A):3337-42.
BACKGROUND: Whether high energy shock waves (HESW), generated by a piezoelectric generator, were able to activate a sonosensitizer, 5-aminolevulinic acid (ALA) and induce inhibition of cell growth in HT-29 human colorectal cancer cells was investigated. MATERIALS AND METHODS: Cell survival and cell death pathways were investigated by cell growth curves, flow cytometry analysis and ELISA nucleosome evaluation. HT-29 cells were exposed to ALA and different HESW treatments: E1 (energy flux density = 0.22 mJ/mm2; 500 and 1000 shots) and E2 (energy flux density = 0.88 mJ/mm2; 500 and 1000 shots). RESULTS: A significant reduction of HT-29 cell growth with respect to untreated cells was observed only after treatment with ALA and HESW E2, 500 shots. In particular, HESWE2, 500 shots, was able to induce an arrest of HT-29 cells exposed to ALA in the G0/G1-phase of the cell cycle. CONCLUSION: HESW is proposed for the sonodynamic treatment of cancer cells. [PubMed Citation] [Order full text from Infotrieve]

15) Kusunoki N, Ito T, Sakurai N, Handa H, Kawai S
A celecoxib derivative potently inhibits proliferation of colon adenocarcinoma cells by induction of apoptosis.
Anticancer Res. 2006 Sep-Oct;26(5A):3229-36.
BACKGROUND: Celecoxib, a selective cyclooxygenase (COX)-2 inhibitor, has a pro-apoptotic effect on colon adenocarcinoma cells via COX-independent mechanisms. MATERIALS AND METHODS: The pro-apoptotic effect of N-(2-Aminoethyl)-4-[5- (4-tolyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzenesulfonamide (TT101), a new derivative of celecoxib, was investigated on the HT-29 and SW480 colon adenocarcinoma cells. Cell proliferation and viability were assessed by incorporation of 5-bromo-2'-deoxyuridine and by the 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt assay, respectively. Apoptosis was detected by identifying DNA fragmentation. Production of prostaglandin E2 by the HT-29 cells was analyzed. RESULTS: TT101 inhibited the proliferation of HT-29 and SW480 cells by inducing apoptosis more potently than celecoxib in a concentration-dependent manner. The COX-2 inhibitory effect of TT101 was weaker than that of celecoxib. CONCLUSION: A slight modification of celecoxib enhanced the pro-apoptotic effect on colon adenocarcinoma cells. [PubMed Citation] [Order full text from Infotrieve]

16) D'Addario C, Di Benedetto M, Izenwasser S, Candeletti S, Romualdi P
Role of serotonin in the regulation of the dynorphinergic system by a kappa-opioid agonist and cocaine treatment in rat CNS.
Neuroscience. 2007 Jan 5;144(1):157-64.
It has been shown that chronic cocaine increases prodynorphin mRNA in the caudate putamen and decreases it in the hypothalamus. In addition, treatment with a kappa-opioid receptor agonist produced the opposite effect on prodynorphin gene expression in these brain regions and also evoked a decrease in the hippocampus. It is already known that kappa-opioid receptor agonists decrease the development of sensitization to some of the behavioral effects of cocaine. The serotonin system has also been shown to regulate dynorphin gene expression and a continuous infusion of fluoxetine induced prodynorphin gene expression in the same pattern as the kappa-opioid agonist (+)(5a,7a,8b)-N-methyl-N-[7-(1-pyrrolidinyl)-1 oxaspiro[4.5]dec-8-yl]-benzeneacetamide (U-69593) in the brain regions investigated. It is interesting to note that treatment with a continuous infusion of cocaine produced different effects on this parameter. To determine whether serotonin plays a role in the regulation of prodynorphin mRNA by kappa-opioid agonists or cocaine, rats were treated with the serotonin depleter parachloroamphetamine (PCA). Beginning 24 h later, rats were treated with the selective kappa-opioid agonist U-69593 for 5 days or continuously with cocaine for 7 days and prodynorphin mRNA was measured. Prodynorphin mRNA was decreased significantly in the hypothalamus, caudate putamen, and hippocampus of rats treated with a single injection of PCA. Subsequent to PCA administration the effects of U-69593 or cocaine on prodynorphin mRNA were differentially affected across brain regions. Prodynorphin gene expression was still increased by U-69593 treatment in the hypothalamus and decreased in the caudate putamen. Cocaine treatment still produced a decrease in this parameter in the hypothalamus and an increase in the caudate putamen. In contrast, in the hippocampus, the decrease in prodynorphin mRNA produced by U-69593 was no longer evident after PCA and cocaine, which previously had no effect, now increased it in the serotonin-depleted group. These findings suggest that serotonin is necessary to maintain normal levels of dynorphin mRNA in all of the investigated brain areas and that the regulation of prodynorphin mRNA expression by chronic treatment with a kappa-opioid receptor agonist or cocaine requires serotonin in the hippocampus, but not in the hypothalamus or caudate putamen. [PubMed Citation] [Order full text from Infotrieve]

17) Paluchowska MH, Bugno R, Charakchieva-Minol S, Bojarski AJ, Tatarczyńska E, Chojnacka-W�jcik E
Conformational restriction in novel NAN-190 and MP3022 analogs and their 5-HT(1A) receptor activity.
Arch Pharm (Weinheim). 2006 Sep;339(9):498-506.
The newly synthesized analogs of NAN-190 containing m-Cl and m-CF(3) substituents in the arylpiperazine moiety and their conformationally restricted counterparts showed a very high 5-HT(1A )receptor affinity. In the LLR test, the flexible compounds 4a and 5a displayed features of a partial agonist and agonist, respectively. The conformational restriction in the tested structures caused alternations in the observed in vivo effects; compounds 4b and 5b were classified as an inactive agent and an antagonist of postsynaptic 5-HT(1A )receptors, respectively. Rigidification of MP3022 and its 5,6-dimethyl analog structures resulted in cis and trans stereoisomers 6b-9b with a 1- and 2-substituted benzotriazole moiety. In both series, in vitro experiments showed that the cis configurations of the compounds were better tolerated by 5-HT(1A) receptor sites than the trans ones. The conformational analysis revealed various spatial regions that can be explored by terminal benzotriazole fragments in those structures. Like the previously described cis-6b, the new ligand cis-7b, displayed features of a postsynaptic 5-HT(1A) receptor agonist, whereas cis-8b was characterized as a partial agonist of those receptor sites. It was suggested that the nonlinear geometry of the above agents has significant influence on the postsynaptic 5-HT(1A )receptor stimulation. [PubMed Citation] [Order full text from Infotrieve]

18) Carroll FI, Blough BE, Huang X, Nie Z, Mascarella SW, Deschamps J, Navarro HA
Synthesis and monoamine transporter binding properties of 2,3-cyclo analogues of 3beta-(4'-aminophenyl)-2beta-tropanemethanol.
J Med Chem. 2006 Jul 27;49(15):4589-94.
A series of cyclo-3beta-(4-aminophenyl)-2beta-tropanemethanol analogues (5a-m) possessing varying linker groups between the 2- and 3-position on the tropane ring were synthesized and evaluated for their monoamine transporter binding properties. The results show that binding to the dopamine and serotonin transporters (DAT and 5-HTT) is highly dependent on the specific linker used. Cyclo-3beta-(4-aminophenyl)-2beta-tropanemethanol pimelic acid ester/amide (5b) had an IC50 of 3.8 nM at the DAT. Cyclo-3beta-(4-aminophenyl)-2beta-tropanemethanol sebacic acid ester/amide (5e) had a Ki of 1.9 nM at the 5-HTT and was 68- and 737-fold selective for the 5-HTT relative to the DAT and NET. Small changes to the size as well as the electrostatic and hydrophobic properties of the 2,3-linker in 5b or 5e led to much less potent analogues at all three transporters. These results suggest that the high affinity for 5b and 5e at the DAT and 5-HTT may be due to their specific conformational properties. [PubMed Citation] [Order full text from Infotrieve]

19) Thomas DR, Soffin EM, Roberts C, Kew JN, de la Flor RM, Dawson LA, Fry VA, Coggon SA, Faedo S, Hayes PD, Corbett DF, Davies CH, Hagan JJ
SB-699551-A (3-cyclopentyl-N-[2-(dimethylamino)ethyl]-N-[(4'-{[(2-phenylethyl)amino]methyl}-4-biphenylyl)methyl]propanamide dihydrochloride), a novel 5-ht5A receptor-selective antagonist, enhances 5-HT neuronal function: Evidence for an autoreceptor role for the 5-ht5A receptor in guinea pig brain.
Neuropharmacology. 2006 Sep;51(3):566-77.
This study utilised the selective 5-ht(5A) receptor antagonist, SB-699551-A (3-cyclopentyl-N-[2-(dimethylamino)ethyl]-N-[(4'-{[(2-phenylethyl)amino]methyl}-4-biphenylyl)methyl]propanamide dihydrochloride), to investigate 5-ht5A receptor function in guinea pig brain. SB-699551-A competitively antagonised 5-HT-stimulated [35S]GTPgammaS binding to membranes from human embryonic kidney (HEK293) cells transiently expressing the guinea pig 5-ht5A receptor (pA2 8.1+/-0.1) and displayed 100-fold selectivity versus the serotonin transporter and those 5-HT receptor subtypes (5-HT(1A/B/D), 5-HT2A/C and 5-HT7) reported to modulate central 5-HT neurotransmission in the guinea pig. In guinea pig dorsal raphe slices, SB-699551-A (1 microM) did not alter neuronal firing per se but attenuated the 5-CT-induced depression in serotonergic neuronal firing in a subpopulation of cells insensitive to the 5-HT1A receptor-selective antagonist WAY-100635 (100 nM). In contrast, SB-699551-A (100 or 300 nM) failed to affect both electrically-evoked 5-HT release and 5-CT-induced inhibition of evoked release measured using fast cyclic voltammetry in vitro. SB-699551-A (0.3, 1 and 3 mg/kg s.c.) did not modulate extracellular levels of 5-HT in the guinea pig frontal cortex in vivo. However, when administered in combination with WAY-100635 (0.3 mg/kg s.c.), SB-699551-A (0.3, 1 or 3 mg/kg s.c.) produced a significant increase in extracellular 5-HT levels. These studies provide evidence for an autoreceptor role for the 5-ht5A receptor in guinea pig brain. [PubMed Citation] [Order full text from Infotrieve]

20) Garcia R, Gano L, Maria L, Paulo A, Santos I, Spies H
Synthesis and biological evaluation of tricarbonyl Re(I) and Tc(I) complexes anchored by poly(azolyl)borates: application on the design of radiopharmaceuticals for the targeting of 5-HT1A receptors.
J Biol Inorg Chem. 2006 Sep;11(6):769-82.
The building blocks fac-[(99m)Tc{kappa(3)-HB(tim(Me))(3)}(CO)(3)] and fac-[(99m)Tc{kappa(3)-R(mu-H)B(tim(Me))(2)}(CO)(3)] [R is H (4a), Ph (5a); tim(Me) is 2-mercapto-1-methylimidazolyl] were obtained almost quantitatively by reacting fac-[(99m)Tc(CO)(3)(H(2)O)(3)](+) with the corresponding scorpionate. These compounds cross the intact blood-brain barrier in mice, with significant retention in the case of 4a and 5a. Using 4a as the lead structure, we have synthesized the functionalized complexes fac-[M{kappa(3)-H(mu-H)B(tim(Bu-pip))(2)}(CO)(3)] [M is Re (8), (99m)Tc (8a); tim(Bu-pip) is methyl[4-((2-methoxyphenyl)-1-piperazinyl)butyl](2-mercapto-1-methylimidazol-5-yl)methanamide] and fac-[M{kappa (3)-H(mu-H)B(tim(Me))(tim(Bu-pip))}(CO)(3)] [M is Re (9), (99m)Tc (9a)] and evaluated their potential as radioactive probes for the targeting of brain 5-HT(1A) serotonergic receptors. The Re complexes exhibit excellent affinity [IC(50)=0.172 +/- 0.003 nM (8); IC(50)=0.65 +/- 0.01 nM (9)] for the 5-HT(1A) receptor. The radioactive congeners ((99m)Tc) have shown an initial brain uptake of 1.38 +/- 0.46%ID g(-1) (8a) and 0.43 +/- 0.12%ID g(-1) (9a), but suffer from a relatively fast washout. [PubMed Citation] [Order full text from Infotrieve]