Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P08908 (5-HT1A)
 5,574 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Administration of various doses of clonidine increased plasma growth hormone levels. Pretreatment with the alpha 2 adrenergic antagonists, yohimbine and 1-(2-pyrimidyl)piperazine, completely blocked clonidine's effect on growth hormone levels. Pretreatment with the 5-hydroxytryptamine3 (5-HT3) receptor antagonist, MDL-72222, the 5-HT1A/5-HT2 antagonist, spiperone, and the mixed beta adrenergic/5-HT1B antagonists, l-propranolol and CGP361A, did not attenuate clonidine-induced increases in growth hormone levels. In contrast, pretreatment with the non-selective 5-HT1/2 antagonist, metergoline, and the 5-HT1C/5-HT2-selective antagonist, mesulergine, reduced clonidine-induced increases in growth hormone levels 81 to 87% without affecting clonidine-induced decreases in locomotor activity. Two other 5-HT1C/5-HT2 antagonists, ritanserin and mianserin, also attenuated (47%) clonidine-induced increases in growth hormone levels. Pretreatment with the noradrenergic neurotoxin, DSP4, did not block clonidine's effect on growth hormone levels. Clonidine administration decreased locomotor activity in both the Fawn-Hooded and the Wistar rat strains to the same extent. On the other hand, clonidine administration failed to increase growth hormone levels in the Fawn-Hooded rat strain. These findings suggest that clonidine stimulates growth hormone secretion by activation of alpha 2 adrenergic heteroreceptors present on 5-HT nerve terminals which, in turn, enhance 5-HT activity via stimulation of postsynaptic 5-HT1C receptors to promote growth hormone releasing factor. Furthermore, either 5-HT1C receptors or alpha 2 adrenergic heteroreceptors or both are functionally sub-sensitive in the Fawn-Hooded rat strain relative to the Wistar rat strain.
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PMID:Functional subsensitivity of 5-hydroxytryptamine1C or alpha 2 adrenergic heteroreceptors mediating clonidine-induced growth hormone release in the Fawn-Hooded rat strain relative to the Wistar rat strain. 135 49

1. Rats were administered either desipramine (DMI) or sertraline daily at doses 7.5 mg kg-1 or 10 mg kg-1, i.p., respectively and the effects on the functional state of hypothalamic neuroendocrine control mechanisms assessed by measurements of plasma hormones following acute drug challenge. The effects of treatment on gross behaviour and brain adrenoceptor density were also determined. 2. Both DMI and sertraline caused significant reduction in activity measured as ambulation and rearing at 14 days of treatment. 3. All animals were chronically cannulated after 14 days of treatment and tested for neuroendocrine response to acute i.v. clonidine (50 micrograms kg-1) or 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, 250 micrograms kg-1) after 21 or more days of treatment. 4. Rats treated with DMI but not sertraline showed a virtually complete suppression of the growth hormone (GH) secretion elicited by clonidine in controls, while the secretion of corticosterone was augmented. 5. Treatment with DMI but not sertraline led to a significantly greater 8-OH-DPAT-induced secretion of prolactin than in the control rats, while the plasma concentrations of corticosterone following 8-OH-DPAT were not influenced by either DMI or sertraline treatment. 6. The density (but not the affinity) of cerebral cortical binding of [3H]-dihydroalprenolol was significantly reduced by DMI treatment. 7. These results show that DMI treatment blunted the sensitivity of post-synaptic alpha 2-adrenoceptors, accompanied by complex interactions manifested as increased responsiveness of alpha 1-adrenoceptors and 5-HT1A receptors. Sertraline had no significant neurendocrine effects at a dose which significantly reduced gross activity.
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PMID:Neuroendocrine response to clonidine and 8-OH-DPAT in rats following chronic administration of desipramine or sertraline. 138 21

Ten healthy subjects received buspirone (30 mg orally) with and without pre-treatment with the 5-HT1A receptor antagonist, pindolol (80 mg over 3 days). Following pindolol treatment the growth hormone and hypothermic responses to buspirone were significantly decreased. There was also a delay in the onset of the prolactin response to buspirone but the total amount of prolactin secretion, calculated as area under the curve, was not significantly reduced. The data suggest that the growth hormone and hypothermic responses to buspirone in humans are mediated by 5-HT1A receptors, but an explanation founded on pharmacokinetic factors cannot presently be excluded. Both this latter possibility and the lack of selectivity of pindolol for 5-HT receptors indicate the need for the further neuroendocrine studies of the mode of action of buspirone, preferably with more selective 5-HT1A receptor antagonists.
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PMID:Effect of pindolol on endocrine and temperature responses to buspirone in healthy volunteers. 157 Mar 92

The effect of lithium administration (800 mg daily for 7 days) on the neuroendocrine and temperature responses to the 5-HT1A receptor agonist, gepirone, was studied in eight healthy male volunteers. Gepirone (20 mg orally) significantly increased plasma levels of prolactin, growth hormone, corticotropin and cortisol, and lowered oral temperature. None of these responses was significantly altered by lithium treatment. The results suggest that the ability of short-term lithium treatment to increase 5-HT-mediated neuroendocrine responses in humans is unlikely to be related to changes in the sensitivity of pre- or post-synaptic 5-HT1A receptors.
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PMID:Lithium and 5-HT1A receptor sensitivity: a neuroendocrine study in healthy volunteers. 166 54

In healthy volunteers, the azapirones--buspirone, ipsapirone, and gepirone--increase plasma cortisol and decrease body temperature; buspirone and gepirone also increase plasma prolactin and growth hormone. Data from animal studies suggest that the ability of azapirones to decrease body temperature and increase corticotropin and corticosterone is mediated by stimulation of presynaptic and postsynaptic serotonin (5-hydroxytryptamine, 5-HT) type 1A subtype receptors, respectively. The mechanism of altered growth hormone and prolactin secretion is less clear. While animal studies implicate changes in dopamine function, current human investigations suggest that 5-HT1A receptors also may be involved in these endocrine responses. Further investigations, using more selective 5-HT receptor antagonists, will be required to resolve this issue.
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PMID:Neuroendocrine effects of azapirones. 197 37

The effects of pindolol on the prolactin (PRL) and growth hormone (GH) responses to intravenous tryptophan (LTP) were studied in eight healthy male volunteers. Pindolol pretreatment (40 mg over 48 h) markedly attenuated the GH response to LTP and modestly, but significantly, reduced the LTP-induced increase in plasma PRL. The disposition of LTP following infusion was not altered by pindolol. While the data are consistent with 5-HT1A receptor mediation of PRL and GH responses to LTP, the intrinsic sympathomimetic actions of pindolol might also be involved in the attenuation of the endocrine responses to LTP.
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PMID:Pindolol decreases prolactin and growth hormone responses to intravenous L-tryptophan. 200 40

The effects of the selective 5-HT1A receptor agonist gepirone (10 and 20 mg orally) on neuroendocrine function and temperature were assessed using a single-blind cross-over design in 12 healthy male volunteers. Gepirone significantly increased plasma levels of ACTH, beta-endorphin, cortisol, prolactin and growth hormone. Following gepirone there was a significant decrease in body temperature and moderate increases in subjective reports of light-headedness, nausea and drowsiness. Our results are consistent with studies in rodents suggesting that 5-HT1A receptor agonists increase ACTH and prolactin secretion and decrease body temperature. Further investigations are needed to determine if the neuroendocrine and temperature effects of gepirone in humans are mediated by 5-HT1A receptors.
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PMID:The effects of gepirone on neuroendocrine function and temperature in humans. 215 31

Increasing brain 5-hydroxytryptamine (5-HT) function in humans raises plasma concentrations of prolactin, growth hormone and ACTH. Measurement of these hormonal responses provides an index of the functional activity of brain 5-HT pathways. More recent strategies have included the use of directly-acting 5-HT receptor agonists to probe the function of specific receptor subtypes; at present these studies are limited by the questionable selectivity of the agonists employed. Using 5-HT neuroendocrine testing it can be shown that lithium specifically increases the prolactin release mediated by 5-HT pathways. Further studies are needed to determine if this effect is caused by an enhanced sensitivity of post-synaptic 5-HT1A receptors.
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PMID:5-HT neuroendocrine responses during psychotropic drug treatment: an investigation of the effects of lithium. 225 42

Certain evidence suggests that buspirone, a novel nonbenzodiazepine anxiolytic, may be a 5-HT1A serotonergic agonist and may antagonize postsynaptic dopaminergic receptors. The latter property raises questions regarding a dyskinesia- or extrapyramidal symptom-inducing potential. We monitored serum prolactin and growth hormone in 10 subjects with generalized anxiety disorder and 10 matched controls before and after 4 weeks of pharmacotherapy. A drug effect upon serotonin-modulated prolactin release or on the tubero-infundibular dopamine axis (prolactin; growth hormone) was negligible at clinically effective dosages of buspirone. Concomitant buspirone levels also failed to demonstrate any significant relationships.
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PMID:Buspirone: effects on prolactin and growth hormone as a function of drug level in generalized anxiety. 272 31

Administration of various doses of DOI (a 5-HT2A/5-HT2C agonist) produced hyperthermia that was significantly less in the FH rat strain relative to the Wistar rat strain. Similarly, administration of various doses of ipsapirone (a 5-HT1A agonist) produced hypothermia that was significantly less in the FH rat strain relative to the Wistar rat strain. Furthermore, m-CPP (a 5-HT agonist)-induced increases in growth hormone levels were also significantly less in the FH rat strain relative to the Wistar rat strain. There was no significant difference in the levels of either 5-HT or 5-HIAA between the two rat strains in the frontal cortex, hippocampus, hypothalamus, and striatum. In the brain stem, however, both 5-HT and 5-HIAA levels were significantly lower in the FH rat strain relative to the Wistar rat strain. On the other hand, 5-HT turnover rate was significantly higher in the hypothalamus and striatum and significantly lower in the hippocampus in the FH rat strain relative to the Wistar rat strain. These findings provide further evidence for altered serotonergic function in the FH rat strain and, in addition, suggest that the FH rat strain may prove to be a useful genetic model for some neuropsychiatric disorders with possible abnormalities in serotonergic function such as depression, obsessive-compulsive disorder, and the eating disorders.
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PMID:Functional and biochemical evidence for altered serotonergic function in the fawn-hooded rat strain. 753 10


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