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Query: UNIPROT:P08908 (5-HT1A)
 5,574 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effects of the non-selective 5-hydroxytryptamine (5-HT) receptor agonist m-chlorophenylpiperazine (m-CPP) on the nociceptive responsiveness in a hot plate and tail flick tests were examined in mice. Intraperitoneal administration of m-CPP (1-10 mg/kg) produced a dose-dependent antinociception in both those tests; the effect of m-CPP in the hot plate test was stronger. The antinociceptive effect of m-CPP in either test was abolished by pretreatment with mesulergine (2 mg/kg), ritanserin (1-2 mg/kg), 5-HT2A/5-HT2C receptor antagonists, and metergoline (0.5-2 mg/kg), a non-selective 5-HT receptor antagonist. On the other hand, spiperone (0.25-0.5 mg/kg), a dopamine, 5-HT1A and 5-HT2A receptor antagonist; pindolol (4-8 mg/kg), a beta-adrenoceptor, 5-HT1A and 5-HT1B receptor antagonist and zacopride (0.1-1 mg/kg) a 5-HT3 receptor antagonist, did not affect the analgesia induced by m-CPP. Neither of the drugs used as putative receptor antagonists changed the nociceptive responsiveness in mice. The obtained results suggest that the analgesia induced by m-CPP is mediated by 5-HT2C receptors.
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PMID:Involvement of 5-HT2C receptors in the m-CPP-induced antinociception in mice. 789 29

1. The pharmacology of a novel 5-HT4 receptor antagonist, SB 204070 has been evaluated in the guinea-pig isolated distal colon longitudinal muscle-myenteric plexus (LMMP). 2. SB 204070 is a highly potent antagonist of 5-HT-evoked cholinergically-mediated contractions in the guinea-pig distal colon. Low concentrations (10-100 pM) produced a shift to the right of the curve (apparent pA2 10.8 +/- 0.1) with no significant effect on the maximum response. With higher concentrations of SB 204070 (300 pM and above), the maximum response to 5-HT was reduced. 3. When tested against the partial 5-HT4 receptor agonist, BIMU 1, SB 204070 was active at similar low concentrations (10 pM and above) but produced a reduction in maximum, with no prior shift to the right of the curve, at all concentrations tested (10-300 pM). 4. The antagonism seen with SB 204070 is unlikely to be due to a non-selective effect since high concentrations (10 nM and 1 microM) of the compound had no effect on cholinergically-mediated contractions evoked by the nicotinic receptor agonist, DMPP, in the same preparation. SB 204070 is unlikely to be an irreversible antagonist since the effects of the compound could be reversed upon washing of the tissue. 5. Radioligand binding studies show that SB 204070 has a greater that 5000 fold selectivity for the 5-HT4 receptor over 5-HT1A, 5-HT1D, 5-HT1E, 5-HT2A, 5-HT2C, 5-HT3, GABAA, BDZ, TBPS, A1 adenosine receptors, alpha 1, alpha 2, beta 1, beta 2 adrenoceptors and D1, D2 and D3 dopamine receptors. 6. SB 204070 is a highly potent, highly selective 5-HT4 receptor antagonist and as such is an important new tool in evaluating the functional role of the 5-HT4 receptor.
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PMID:The effects of SB 204070, a highly potent and selective 5-HT4 receptor antagonist, on guinea-pig distal colon. 792 4

The phenylisopropylamine hallucinogen 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) produced dose-related increases in plasma concentrations of prolactin, adrenocorticotropic hormone (ACTH) and corticosterone but not growth hormone in rats. Pretreatment with metergoline (serotonin, 5-HT1/5-HT2 antagonist), ritanserin and mianserin (5-HT2A/5-HT2C antagonists) significantly attenuated DOM-induced increases in prolactin, ACTH and corticosterone, whereas mesulergine (5-HT2A/5-HT2C antagonist) pretreatment significantly attenuated DOM-induced increases in plasma prolactin and ACTH but not corticosterone. Pretreatment with propranolol (beta adrenoceptor antagonist that also has high binding affinity for 5-HT1A, 5-HT1B and 5-HT2C sites), MDL-72222 and ondansetron (5-HT3 antagonists) attenuated DOM's effect on plasma prolactin, but did not attenuate DOM-induced increases in either ACTH or corticosterone. On the other hand, spiperone (5-HT1A/5-HT2A/D2 antagonist) pretreatment significantly attenuated DOM-induced increases in ACTH but not corticosterone. These findings demonstrate involvement of 5-HT2A/5-HT2C and 5-HT3 receptors in mediating DOM-induced increases in plasma prolactin, whereas DOM-induced increases in ACTH appear to be mediated by stimulation of 5-HT2A receptors. DOM-induced corticosterone secretion appears to be mediated by stimulation of 5-HT2A and/or 5-HT2C receptors. DOM does not affect growth hormone secretion in rats.
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PMID:Role of various 5-HT receptor subtypes in mediating neuroendocrine effects of 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) in rats. 796 7

In this study, we examined the interaction of 5-HT1A and 5-HT2A receptors in the rat medial prefrontal cortex (mPFc) using the techniques of extracellular single unit recording and microiontophoresis. The iontophoresis of the selective 5-HT1A receptor agonist (+-)-8-hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT) produced a current-dependent suppression (2.5-20 nA) of the basal firing rate of spontaneously active mPFc cells. The iontophoretic (5-10 nA) and systemic administration (0.1-0.5 mg/kg, i.v.) of the 5-HT2A/5-HT2C receptor antagonist ritanserin and the selective 5-HT2A receptor antagonist MDL 28727 significantly potentiated and prolonged 8-OHDPAT's suppressant action. In addition, the systemic administration of another selective 5-HT2A antagonist MDL 100907, but not its less active enantiomer MDL 100009, also potentiated and prolonged 8-OHDPAT's action. The potentiating effect of the 5-HT2A receptor antagonists on the action of 8-OHDPAT is specific in that neither the iontophoresis of ritanserin nor MDL 28727 altered the suppressant action produced by the iontophoresis of the 5-HT3 receptor agonist 2-methylserotonin onto mPFc cells. Moreover, the suppressant action of 8-OHDPAT was not altered by the systemic administration of the selective 5-HT3 receptor antagonist granisetron (0.1-0.5 mg/kg, i.v.). On the other hand, the iontophoresis of a low current (0.5 nA) of the 5-HT2A,2C receptor agonist (+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) potentiated the excitation induced by the iontophoresis of l-glutamate on quiescent mPFc cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Electrophysiological evidence for a functional interaction between 5-HT1A and 5-HT2A receptors in the rat medial prefrontal cortex: an iontophoretic study. 797

The influence of cocaine exposure on serotonergic neurons and postsynaptic 5-HT1A receptor-mediated responses was evaluated by measuring neuroendocrine responses to a serotonin (5-HT) releaser or a 5-HT1A agonist. Male rats received cocaine (15 mg/kg, i.p.) or saline twice daily for 7 days. Forty-two hr after the final cocaine injection, the 5-HT releaser d-fenfluramine (0, 0.2, 0.6, 2, or 5 mg/kg, i.p.) or the 5-HT1A agonist, 8-OH-DPAT (0, 10, 50, 200 or 500 micrograms/kg, s.c.) were administered. Blood samples were then collected for analysis of plasma ACTH, prolactin, and renin concentrations. The ACTH responses to d-fenfluramine and 8-OH-DPAT were inhibited in cocaine pretreated rats. However, the prolactin responses to d-fenfluramine and 8-OH-DPAT were not significantly modified by cocaine exposure. Additionally, the renin response to d-fenfluramine was unaltered by repeated cocaine administration, while 8-OH-DPAT did not alter renin secretion in either pretreatment group. In contrast to published reports which show that cocaine exposure produces supersensitive 5-HT2A and/or 5-HT2C receptor-mediated responses, the present data suggest that repeated cocaine exposure produces subsensitivity to at least some postsynaptic 5-HT1A receptors. Cocaine-induced deficits in the ACTH response to 5-HT releasers may reflect 5-HT1A receptor subsensitivity, but presynaptic deficits cannot be excluded. Examination of the ACTH response to 5-HT1A agonists may represent a valuable approach to determine deficits in 5-HT function in human cocaine abusers.
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PMID:Repeated cocaine exposure inhibits the adrenocorticotropic hormone response to the serotonin releaser d-fenfluramine and the 5-HT1A agonist, 8-OH-DPAT. 798 71

The phenomenon of prepulse inhibition (PPI) of the acoustic startle reflex is widely used as an operational measure of sensorimotor gating mechanisms. Because sensorimotor gating abnormalities have been identified in schizophrenic patients, the exploration of the neural substrates involved in PPI may provide insight into the neural dysfunctions underlying this disorder. Both dopaminergic and glutamatergic systems are involved in the modulation of PPI in rats. In addition, the present studies demonstrate complex serotonergic influences in this phenomenon. Specifically, both the 5-HT2 agonist, DOI, (2,5-dimethoxy-4-iodoamphetamine), and the 5-HT1B agonist, RU 24969, [5-methoxy-3(1,2,3,6)tetrahydropyridin-4- yl]-1H-indole, potently and reversibly disrupted PPI. The 5-HT2C agonist mCPP, [1-(m)-chlorophenyl-piperazine], was ineffective. Furthermore, ketanserin (2.0 mg/kg) and haloperidol (0.1 mg/kg) but not (+/-)propranolol (20.0 mg/kg) blocked the effect of DOI. In addition, the same doses of haloperidol, and, to a lesser extent, (+/-)propranolol, prevented the disruption of PPI induced by RU 24969. Together with previous reports of 5-HT1A involvement in PPI, these results argue for multiple serotonergic mechanisms in the modulation of PPI.
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PMID:Multiple serotonin receptor subtypes modulate prepulse inhibition of the startle response in rats. 798 82

1-(3-Chlorophenyl)piperazine (mCPP) (0.125-1.0 mg/kg i.p.), previously shown to inhibit social interaction, dose-dependently reduced exploration of the open arms of an elevated plus-maze. These findings suggest anxiogenic properties. The effect of mCPP was more potently inhibited by 1-(1-naphthyl)piperazine than by ketanserin, indicative of its mediation via activation of 5-HT2C rather than 5-HT2A receptors. The 5-HT1B receptor agonist CGS 12066B did not antagonise the anxiety-like response to mCPP, and further reduced exploration at the highest dose tested (10 mg/kg i.p.). Depletion of serotonin (5-HT) by p-chlorophenylalanine (PCPA, 150 mg/kg/day x 3) did not prevent the response, although PCPA itself increased open arm exploration. The 5-HT1A/B and beta-adrenoceptor antagonist 1-propanolol (5 mg/kg i.p.) and the peripheral beta 1-receptor antagonist atenolol (20 mg/kg i.p.) showed no significant activity on the plus-maze either alone or against the anxiogenic effect of mCPP. These results indicate that mCPP induces anxiety in the rat in the elevated plus-maze primarily by stimulation of postsynaptic 5-HT2C receptors, and suggest that sympathomimetic effects of mCPP are not involved.
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PMID:Evidence that mCPP-induced anxiety in the plus-maze is mediated by postsynaptic 5-HT2C receptors but not by sympathomimetic effects. 798 84

The serotonin (5-HT) is implicated in many centrally-regulated functions and has shown to be involved in affective disorders, such as depression and anxiety disorders. Recent progress in pharmacology and molecular neurobiology have confirmed the concept of the heterogeneity of 5-HT receptors and permitted reformulation of new hypothesis concerning antidepressant mechanisms of action, in particular those concerning serotoninergic receptors. Up to date, among the 5-HT defined sites, only 13 have been cloned, and several subfamilies have been described. Particularly, the 5-HT1 family containing receptors: 5-HT1A, 5-HT1B/1D, 5-HT1E and 5-HT1F. The 5-HT2 family includes receptors that stimulate phospholipase C: 5-HT2A (previously termed 5-HT2), 5-HT2B and 5-HT2C (previously termed 5-HT1C). Concerning 5-HT2 family, it is possible that some 5-HT binding drugs properties initially attributed to 5-HT2A receptors, might well be mediated by 5-HT2C receptors. Recently, medifoxamine (Cledial) activities on 5-HT systems have been shown. In particular, these activities are related on 5-HT2C and/or 5-HT2A binding sites. Results indicate that, in vitro, medifoxamine affinities (Ki) are near to 1 microM, for both 5-HT2C and 5-HT2A sites (ratio = 1.42). On the other hand, m-CPP, an 5-HT2C agonist, considered as a reference compound, has the same affinities that medifoxamine, but a higher one for 5-HT2A (ratio = 3.42). In animals models considered as predictive for psychotropic activity in human, we investigate in rat the impact of medifoxamine on 5-HT2C receptors, using Learned-Helplessness model (LH) and the social interaction test.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The role of type 2 serotonin receptors, 5-HT2A and 5-HT2C, in depressive disorders: effect of medifoxamine]. 798 7

The present study characterized the serotonin (5-HT) receptor subtypes mediating adrenal corticotropic hormone (ACTH) and corticosterone responses to 5-HT agonists in conscious rats. The 5-HT2A/5-HT2C agonist (+/-(-)1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HC1 (DOI) increased plasma ACTH and corticosterone in a dose-dependent manner. The 5-HT2A/5-HT2C antagonist ritanserin (0.01 and 0.1 mg/kg sc) inhibited the DOI-induced increase in plasma ACTH, but not corticosterone. Low doses of spiperone (0.01 and 0.1 mg/kg sc) significantly reduced the ACTH response to DOI. Because spiperone has a higher affinity for 5-HT2A than 5-HT2C receptors, these data suggest that DOI stimulates ACTH secretion through 5-HT2A receptors. 5-methoxy-3-[1,2,3,4-tetrahydro-4-pyridinyl]-1H-indole (RU 24969) is a potent 5-HT1A/1B and moderate 5-HT2C agonist that also has been suggested to release 5-HT. However, p-chlorophenylalanine (PCPA) did not reduce the effect of RU 24969 on plasma ACTH, suggesting that RU 24969 only acts as a direct agonist. 6-methyl-1-[1-methylethyl]ergoline-8-carboxylic acid (LY53857) injected into the lateral cerebral ventricles (i.c.v.) inhibited the ACTH, but not corticosterone response to peripheral injection of RU 24969, suggesting that central 5-HT2A/2C receptors mediate the ACTH response. LY53857 injection (i.c.v.) also inhibited the effect of p-chloroamphetamine (i.c.v.) on plasma ACTH. However, the corticosterone response was not inhibited by LY53857, suggesting a distinct location of 5-HT receptors regulating corticosterone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evidence that ACTH secretion is regulated by serotonin2A/2C (5-HT2A/2C) receptors. 799 80

The administration of various doses of the phenylisopropylamine hallucinogen 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) to rats produced dose-related decreases in 1-hr food intake in a food-restricted paradigm and in locomotor activity. DOM also produced dose-related increases in temperature. Pretreatment with propranolol [a beta adrenoceptor antagonist that also has high binding affinity for serotonin (5-HT) 5-HT1A, 5-HT1B and 5-HT2C sites], bemesetron or ondansetron (5-HT3 antagonists) did not attenuate either DOM-induced hypophagia or hyperthermia. In contrast, pretreatment with metergoline (a 5-HT1/5-HT2 antagonist) and ritanserin (a 5-HT2A/5-HT2C antagonist) significantly attenuated both DOM-induced hypophagia and hyperthermia. However, pretreatment with mesulergine (a 5-HT2C/5-HT2A antagonist) significantly attenuated DOM-induced hyperthermia but not hypophagia. On the other hand, spiperone (5-HT1A/5-HT2A/D2 antagonist) pretreatment significantly attenuated DOM-induced hyperthermia but accentuated DOM-induced hypophagia. Daily administration of DOM (1.0 mg kg-1 day-1) produced complete tolerance to its hypophagic effect by day 4 but did not produce cross-tolerance to m-chlorophenylpiperazine-induced hypophagia. In contrast, daily administration of DOM for 7 days did not produce either tolerance to its hyperthermic effect or modify m-chlorophenylpiperazine-induced hyperthermia in rats. These findings suggest that DOM-induced hypophagia and hyperthermia in rats are mediated by stimulation of 5-HT2a receptors.
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PMID:Evidence that 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane-induced hypophagia and hyperthermia in rats is mediated by serotonin-2A receptors. 803 8


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