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Query: UNIPROT:P08908 (
5-HT1A
)
5,574
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Antisocial behaviour is both heterogeneous and the product of interacting genetic and environmental factors acting at different levels of causation. Heritability studies show that individual differences in predisposition to antisocial behaviour are transmitted vertically in families by genetic mechanisms. Owing to aetiological heterogeneity and complexity, study of a variety of other behavioural phenotypes may shed more light on the antecedents of antisocial behaviour than direct studies on antisocial behaviour. Identification of genetic vulnerability factors would clarify mechanisms of vulnerability and the role of the environment. Direct gene analysis and genetic linkage analysis have identified structural variants in genes involved in neurotransmitter function, and some progress has been made towards relating these genetic variants to antisocial personality and other behaviours. Thyroid hormone receptor variants can cause attention deficit/hyperactivity disorder, and a monoamine oxidase A variant leads to aggressive behaviour in one family. Direct gene analyses have revealed non-conservative amino acid substitutions and structural variants (generally rare) at DRD2, DRD3 and DRD4 dopamine receptors and
5-HT1A
, 5-HT2A,
5-HT2C
and 5-HT7 serotonin receptors. The stage is set to identify the phenotypic significance of these as well as genetic variants at other loci which may be relevant as candidate genes for antisocial behaviour and related behavioural differences.
...
PMID:Direct analysis of candidate genes in impulsive behaviours. 886 74
Intraperitoneal administration of m-chlorophenylpiperazine (m-CPP) to Wistar rats produced hyperthermia with a peak effect at 30 min. Pretreatment with low doses of metergoline (5-HT1/5-HT2 antagonist), mesulergine and mianserin (
5-HT2C
/5-HT2A antagonists) blocked m-CPP-induced hyperthermia. Pretreatment with propranolol (beta-adrenergic receptor antagonist that also has binding affinity for
5-HT1A
, 5-HT1B and 5-HT2B sites), yohimbine (alpha 2-noradrenergic antagonist that also has binding affinity for 5-HT2B sites), MDL-72222 or ondansetron (5-HT3 antagonists) did not attenuate m-CPP-induced hyperthermia. Only high doses of ketanserin, LY-53857 and ritanserin (5-HT2A/
5-HT2C
antagonists) as well as spiperone (
5-HT1A
/5-HT2A/D2 antagonist) attenuated m-CPP-induced hyperthermia. Daily administration of m-CPP produced complete tolerance to its hyperthermic effect by day 5. However, there was no cross-tolerance to 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI, a 5-HT2A agonist that also has high affinity for
5-HT2C
receptors)-induced hyperthermia. m-CPP-induced increases in temperature were found to be significantly less in the Fawn-Hooded (FH) rat strain as compared to the Wistar rat strain; in prior studies, FH rats have been found to be subsensitive to other
5-HT2C
-mediated pharmacologic responses. Altogether, these findings suggest that m-CPP-induced hyperthermia in rats is mediated by selective stimulation of
5-HT2C
receptors.
...
PMID:Evidence that m-chlorophenylpiperazine-induced hyperthermia in rats is mediated by stimulation of 5-HT2C receptors. 886 72
Effects of paroxetine (10 mg/kg PO, twice daily, 14 days) on 5-HT receptor subpopulations in the brain were evaluated pharmacologically, electrophysiologically and biochemically in male Wistar rats. Imipramine was used for comparison. Repeated paroxetine antagonized the 8-OH-DPAT-induced behavioural syndrome (a
5-HT1A
effect); imipramine showed similar, yet weaker, activity. The 5-HT-or 8-OH-DPAT-induced inhibition of population spikes in hippocampal slices was increased by both those repeated antidepressants. Repeated (or acute) paroxetine decreased the density of and increased the affinity for
5-HT1A
receptors ([3H]-8-OH-DPAT used as ligand) in the hippocampus, while imipramine induced opposite effects. m-Chlorophenyl piperazine (m-CPP)-evoked exploratory hypoactivity, a
5-HT2C
effect, was reduced by repeated paroxetine, but not by imipramine. Either of the antidepressants given repeatedly antagonized TFMPP-induced hyperthermia (another putative
5-HT2C
effect). 5-HTP-induced head twitches (a 5-HT2A effect) were inhibited by repeated paroxetine or imipramine. Either antidepressant given repeatedly decreased the density of 5-HT2A receptors ([3H]-ketanserin as a ligand) in the brain cortex, but did not change their affinity. The present results indicate that paroxetine given repeatedly induces secondary changes in 5-HT2 receptors, which lead to reduction of the 5-HT2 neurotransmission (reduced responsiveness of 5-HT2 postsynaptic receptors). The consequences of the secondary changes in
5-HT1A
receptors, found here still await clarification.
...
PMID:The effects of paroxetine given repeatedly on the 5-HT receptor subpopulations in the rat brain. 888 Sep 46
The immediate serotonin (5-HT) precursor, 5-hydroxy-L-tryptophan (L-5-HTP), is an investigational treatment for myoclonic disorders. Its mechanism of action in humans is incompletely understood. We measured the density of subtypes of 5-HT1 and 5-HT2 receptors and the affinity of 5-HT and L-5-HTP in vitro in the human brainstem and cortex, regions associated with subcortical and cortical myoclonus, respectively. In the cortex, the rank order of 5-HT receptor subtype Bmax was 5-HT2A (low-affinity),
5-HT1A
, 5-HT uptake sites, 5-HT1D,
5-HT2C
, 5-HT1E/F, and 5-HT2A (high-affinity) sites. In the brainstem, the rank order was 5-HT uptake sites, 5-HT1D,
5-HT2C
,
5-HT1A
, and 5-HT2A(L) sites. Specific binding at 5-HT1E/F and high-affinity 5-HT2A sites was too low for characterization. In competition studies, 5-HT had high affinity for
5-HT1A
and
5-HT2C
sites in the brainstem and cortex, but L-5-HTP was > 1,000-fold less active. These data support the hypothesis that in humans L-5-HTP stimulates 5-HT receptors in the CNS only after conversion to 5-HT. They also indicate in the human brainstem a prominence of
5-HT1A
sites and paucity of 5-HT1D, 5-HT1E/F, and 5-HT2A sites, which has implications for brainstem-mediated myoclonus and response to serotonergic drugs.
...
PMID:Human brainstem serotonin receptors: characterization and implications for subcortical myoclonus. 893 89
In recent years the family of mammalian serotonin receptors has grown to 14 different subtypes, characterized by pharmacological or molecular biological techniques. In parallel, new ligand molecules have been developed for their study. However, selective ligands are not yet available to study every one of them. In addition the degree of selectivity of ligands, hitherto regarded as specific for a particular receptor subtype has been called in question by their affinities for newly discovered receptors. Consequently, a re-evaluation of past ligand receptor autoradiography work is necessary in view of the redefined receptor profiles of these ligands, and the introduction of newly developed ligands. A further difficulty for the characterization of these receptors is the absence of selective antagonist ligands which, for some of the subtypes, have become available only recently. In an attempt to overcome these difficulties we have combined in situ hybridization histochemistry and receptor ligand autoradiography to study the regional and cellular localization of several serotonin receptors in the rodent brain. In addition, for some receptors, we have expanded these studies to primates, including humans. We have found that the distribution of
5-HT1A
receptors in monkey brain, labelled with the agonist 3H-8-OH-DPAT and the antagonist 3H-WAY 100635 was very similar at the levels examined, and corresponded well with that observed for the cells containing mRNA coding for this receptor, confirming the somatodendritic localization of
5-HT1A
receptors in monkey brain. The labelling conditions to visualize 5-HT1F receptors in guinea pig brain, namely 3H-sumatriptan in the presence of 10(-8) M 5-CT to block 5-HT1D receptors, are suitable for visualizing this receptor, since the results agreed with those observed by in situ hybridization. By using 3H-ketanserin and 3H-mesulergine in parallel with in situ hybridization using the corresponding oligonucleotides, we were able to show that these ligands label respectively 5-HT2A and
5-HT2C
binding sites in monkey brain. 5-HT4 receptors were localized in the brain of several species including humans by using 125I-SB 207710. In situ hybridization experiments performed in guinea pig confirmed that 5-HT4 receptors are localized on the terminals of the striatopallidal and striatonigral projections. 5-HT7 binding sites were labelled in rat and guinea pig brains by incubating with 3H-5-CT in the presence of 100 microM WAY 100135 and 250 microM GR 127935; the distribution obtained in both species agreed, in general, with that of the corresponding mRNA coding for them. These results are an illustration of the understanding of our current knowledge of the chemical neuroanatomy of the mammalian 5-HT system.
...
PMID:5-HT receptors in mammalian brain: receptor autoradiography and in situ hybridization studies of new ligands and newly identified receptors. 896 27
YM992, (S)-2-[[(7-fluoro-4-indanyl)oxy]methyl]morpholine monohydrochloride, exhibited the biochemical profile of a selective serotonin (5-HT) reuptake inhibitor (SSRI) with 5-HT2A receptor antagonistic activity. YM922 showed the same high affinity as fluoxetine against the 5-HT reuptake site (Ki = 21 nM) and a similar affinity to that of crazodone against the 5-HT2A receptor (Ki = 86 nM). In other receptor binding studies, an affinity for the adrenergic alpha 1 receptor (Ki = 200 nM) and
5-HT2C
receptor (Ki = 680 nM) was observed. In a monoamine uptake study, YM992 showed a selective 5-HT uptake inhibition (IC50 = 0.15 microM), but only very weakly inhibited both noradrenaline (NA) and dopamine (DA) uptake (IC50 = 3.1 microM (NA), > 10 microM (DA)). YM992 was also found to potently inhibit the aggregation of human platelets (IC50 = 1.9 microM), revealing antagonistic activity for the 5-HT2A receptor in vitro. Enhanced serotonergic neurotransmission, in particular that mediated by the
5-HT1A
receptor, has recently been reported to be important in the long-term treatment of depressive disorders with antidepressants. In addition, some
5-HT1A
receptor-mediated responses are known to be potentiated by co-administration of 5-HT2A receptor antagonists. Thus, YM992, having both selective 5-HT reuptake inhibition and 5-HT2A antagonistic activity, might show potent therapeutic activity as a novel antidepressant in comparison with conventional SSRIs.
...
PMID:Biochemical profile of YM992, a novel selective serotonin reuptake inhibitor with 5-HT2A receptor antagonistic activity. 902 10
1. The authors have tested several 5-HT selective agonists and antagonists (
5-HT1A
/1B, 5-HT2A/2B/2C, 5-HT3 or 5-HT4), an uptake inhibitor and 5-HT depletors in the autoshaping learning task. 2. The present work deals with the receptors whose stimulation increases or decreases learning. 3. Impaired consolidation of learning was observed after the presynaptic activation of 5-HT1B, 5-HT3 or 5-HT4 or the blockade of postsynaptic
5-HT2C
/2B receptors. 4. In contrast, an improvement occurred after the presynaptic activation of
5-HT1A
,
5-HT2C
, and the blockade of presynaptic 5-HT2A,
5-HT2C
and 5-HT3 receptors. 5. The blockade of postsynaptic
5-HT1A
, 5-HT1B, 5-HT3 or 5-HT4 receptors and 5-HT inhibition of synthesis and its depletion did no alter learning by themselves. 6. The present data suggest that multiple pre- and postsynaptic serotonergic receptors are involved in the consolidation of learning. 7. Stimulation of most 5-HT receptors increases learning, however, some of 5-HT subtypes seem to limit the data storage. 8. Furthermore, the role of 5-HT receptors in learning seem to require an interaction with glutamatergic, GABAergic and cholinergic neurotransmission systems.
...
PMID:A pharmacological analysis of serotonergic receptors: effects of their activation of blockade in learning. 906 74
The behavioral profiles of five clinically used selective serotonin reuptake inhibitors (SSRIs) citalopram, paroxetine, sertraline, fluvoxamine and fluoxetine, have been compared in animal models of antidepressant (mouse forced swim test), anxiolytic (exploration of black and white test box and foot-shock-induced ultrasonic vocalization in the rat) and antiaggressive (isolation-induced aggressive behavior in the mouse) activity. the results are discussed in relation to receptor binding data from the literature. Furthermore, affinities for the sigma 1 and sigma 2 binding sites are presented. Citalopram reversed the immobility induced by forced swimming with a potency similar to that of imipramine. Paroxetine, fluvoxamine and fluoxetine reversed swim-induced immobility less potently and with a maximum of 40-50% reversal. Citalopram produced a mixed anxiogenic-/anxiolytic-like response in rats tested in the two-compartment black and white box. Paroxetine induced an anxiogenic-like response at low doses and the other SSRIs were without major effects. Citalopram and paroxetine inhibited footshock-induced ultrasonic vocalization with high potencies. The dose-response curve was biphasic for citalopram with a maximum of 64% inhibition. Sertraline and fluvoxamine inhibited the vocalization less potently, and fluoxetine induced a weak inhibitory effect corresponding to a maximum of 32%. Sertraline, fluvoxamine and fluoxetine inhibited isolation-induced aggressive behavior, whereas citalopram and paroxetine were inactive. Both 5-HT1 and 5-HT2 receptors are involved, and there was a functional interaction between
5-HT1A
and 5-HT2A or
5-HT2C
receptors, as ritanserin potentiated the antiaggressive effect of 1,5-HTP as well as that of 8-OH-DPAT.
...
PMID:Behavioral profiles of SSRIs in animal models of depression, anxiety and aggression. Are they all alike? 908 57
The serotonin reuptake inhibitor, fluoxetine (10.0 mg/kg, s.c.), elicited penile erections in rats. Selective blockade of
5-HT1A
autoreceptors with WAY 100,635 ((N-(2-[4-(2-methoxyphenyl)-1- piperazinyl]ethyl)-N-(2-pyridinyl) cyclo-hexanecarboxamide) (0.16 mg/kg, s.c.), or of 5-HT1B autoreceptors with GR 127,935 (N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-2'-methyl-4'-(5-me thyl- 1,2,4-oxadiazol-3-yl)biphenyl-4-carboxamide) (2.5 mg/kg, s.c.), slightly (1.5- to 2-fold) increased fluoxetine-induced penile erections. However, conjoint administration of WAY 100,635 and GR 127,935 markedly (5-fold) potentiated induction of penile erections by fluoxetine. Penile erections were abolished by the novel
5-HT2C
receptor antagonist, SB 206,553 (5 methyl-1-(3-pyridil-carbamoyl)-1,2,3,5- tetrahydropyrrolo[2,3-f]indole). These data provide functional evidence for redundancy in autoreceptor control of 5-HT release. Combined blockade of
5-HT1A
and 5-HT1B autoreceptors markedly enhances the actions of serotonin reuptake inhibitors.
...
PMID:Potentiation of fluoxetine-induced penile erections by combined blockade of 5-HT1A and 5-HT1B receptors. 908 55
The influence of 5-HT receptor agonists on the expression of BDNF in brain was determined. Administration of a hallucinogenic 5-HT2A /2C receptor agonist, but not a
5-HT1A
receptor agonist, resulted in a significant but differential regulation of BDNF mRNA levels in hippocampus and neocortex. In the hippocampus, the 5-HT2A /2C receptor agonist significantly decreased BDNF mRNA expression in the dentate gyrus granule cell layer but did not influence expression of the neurotrophin in the CA subfields. In parietal cortex and other neocortical areas, but not piriform cortex, the 5-HT2A /2C receptor agonist dramatically increased the expression of BDNF mRNA. The effect of the 5-HT2A /2C receptor agonist on BDNF mRNA in both the hippocampus and the neocortex was blocked by pretreatment with a selective 5-HT2A, but not
5-HT2C
, receptor antagonist. The expression of BDNF mRNA in the hippocampus is reported to be decreased by stress, raising the possibility that the 5-HT2A receptor mediates this effect. Pretreatment with ketanserin, a 5-HT2A /2C receptor antagonist, significantly blocked the stress-induced downregulation of BDNF mRNA in hippocampus, in support of this hypothesis. The results of this study raise the possibility that regulation of BDNF expression by hallucinogenic 5-HT2A receptor agonists leads to adaptations of synaptic strength in the hippocampus and the neocortex that may mediate some of the acute and long-term behavioral effects of these agents.
...
PMID:5-HT2A receptor-mediated regulation of brain-derived neurotrophic factor mRNA in the hippocampus and the neocortex. 909
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