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Query: UNIPROT:P08908 (
5-HT1A
)
5,574
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The effect of serotoninergic activation on gonadotropin and prolactin release were analysed in 16-day-old intact female rats. In the first experiment, females were decapitated 30 min after i.p. administration of 100 mg/kg of
5-hydroxytryptophan
(
5-HTP
) or vehicle; in the second experiment the rats were decapitated 15 and 30 min after i.p. injection of vehicle or some doses (0.1, 1 and 10 mg/kg) of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), a selective agonist of the serotonin (5-HT)1A receptors. We found that: 1) serum follicle-stimulating hormone (FSH), luteinizing-hormone (LH) and prolactin concentrations increased after
5-HTP
administration; 2) serum LH and prolactin concentrations and pituitary prolactin content increased after administration of 8-OH-DPAT. Our results indicate that in prepubertal rats, activation of serotoninergic system stimulated gonadotropin and prolactin release, and that
5-HT1A
receptors are involved in this effect. In addition, the simultaneous increase in serum and pituitary prolactin content suggests that 8-OH-DPAT enhances prolactin synthesis.
...
PMID:Gonadotropin and prolactin secretion in prepubertal female rats treated with 8-hydroxy-2-(di-n-propylamino) tetralin. 751 Jan 11
The role of the serotoninergic system in the control of prolactin (PRL) secretion has been studied in prepubertal male rats. Serum PRL concentration was measured in 16-day-old male rats at different times after the administration of
5-hydroxytryptophan
(
5-HTP
), a precursor of serotonin (5-HT) synthesis, alone or in combination with fluoxetine, a specific inhibitor of 5-HT uptake; DL-p-parachlorophenylalanine (PCPA), an inhibitor of 5-HT synthesis; and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a selective agonist of
5-HT1A
receptors. Also, serum PRL concentration and pituitary content were measured after
5-HTP
administration in castrated males implanted with silastic capsules containing testosterone or 5 alpha-androstane-3 alpha,17 beta-diol (alpha-diol). We found that: the reduction in serotoninergic activity after PCPA administration did not modify serum PRL concentrations; the stimulatory effect of
5-HTP
on PRL secretion was not observed before day 16; the effects of
5-HTP
or
5-HTP
and fluoxetine were similar in intact and orchidectomized males; a significant increase in PRL secretion took place after 8-OH-DPAT administration; the duration of the stimulatory effect of
5-HTP
increased after alpha-diol treatment; and pituitary PRL content increased after
5-HTP
injection in intact males and decreased in castrated males treated with testosterone or alpha-diol.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Serotoninergic control of prolactin secretion in prepubertal male rats. 752 55
1. Selective antagonism of 5-HT4 receptors may provide therapeutic benefit in certain disorders of the myocardium, alimentary and lower urinary tract. We now report on RS 39604, a novel and selective 5-HT4 receptor antagonist and compare its pharmacological properties with those of SB 204070. 2. In guinea-pig striatal membranes, both RS 39604 and SB 204070 inhibited specific binding of [3H]-GR 113808 in a concentration-dependent manner yielding pKi estimates of 9.1 and 10.9, respectively. RS 39604 displayed a low affinity (pKi < 6.5) for
5-HT1A
, 5-HT2C, 5-HT3, alpha 1c, D1, D2, M1, M2, AT1, B1 and opioid mu receptors and moderate affinity for sigma 1, (pKi = 6.8) and sigma 2 (pKi = 7.8) sites. 3. In the rat isolated oesophagus, precontracted with carbachol, RS 39604 (30-300 nM) behaved as a competitive antagonist towards 5-HT-induced relaxation (pA2 = 9.3; Schild slope = 1.0). We and others have shown previously that SB 204070 behaves as an unsurmountable antagonist in this preparation (pA2 approximately 10.5). In the guinea-pig isolated ileal mucosa, RS 39604 (30 nM) antagonized 5-MeOT-induced increase in short-circuit current (pA2 = 9.1). 4. In anaesthetized vagotomized micropigs, RS 39604, administered by the i.v. or intraduodenal (i.duod.) route, produced dose-dependent inhibition of 5-HT-induced tachycardia (ID50 = 4.7 micrograms kg-1, i.v. and 254.5 micrograms kg-1, i.duod). At maximal doses of 30 micrograms kg-1, i.v. and 6 mg kg-1, i.duod., the inhibitory effects of RS 39604 lasted for more than 6 h. In this preparation, SB 204070 was as potent as RS 39604by the i.v. route but was inactive by the intraduodenal route at doses up to 3 mg kg-1.5. In conscious mice, RS 39604, administered by the i.p. or p.o. route, produced dose-depend entinhibition of
5-hydroxytryptophan
(
5-HTP
)-induced diarrhoea (ID50= 81.3 microg kg-1, i.p. and 1.1 mg kg-1,p.o.). In this assay, SB 204070 was inactive by the oral route at doses up to 30 mg kg-1.6. In anaesthetized guinea-pigs, RS 39604 antagonized the contractile effect of 5-HT in the proximal colon by producing parallel, dextral displacement of the dose-response curve to 5-HT. The mean dose ratios to 5-HT at 0.1 mg kg-1, i.v., 1 mg kg-1, i.v. and 10 mg kg-1, i.duod. were 4.6, 30.7 and 10.8,respectively. SB 204070 behaved as an unsurmountable antagonist in this assay.7. In a model of visceral pain in conscious rats, RS 39604 (0.01-1 mg kg-1, i.v.) did not affect colorectal distension-induced increases in arterial pressure whereas morphine (1 mg kg-1, i.v.) produced significant inhibition of the response, implying that 5-HT4 receptors are not involved in nociception in this model.8. The data suggest that RS 39604 is a high affinity and selective 5-HT4 receptor antagonist that is orally active and long-lasting in vivo. It is concluded that RS 39604 may be the preferable probe to use for investigating the physiological and pathophysiological role of 5-HT4 receptors in vivo.
...
PMID:RS 39604: a potent, selective and orally active 5-HT4 receptor antagonist. 758 7
Lithium elicits opposite effects on two behavioural syndromes in rats: enhancement of the
5-HT1A
-linked serotonin syndrome and attenuation of the 5-HT2-linked wet dog shakes. The ability of intracerebroventricular (ICV) myo-inositol or forskolin to reverse the enhancement of the serotonin syndrome by lithium was tested in rats that were fed chronic dietary lithium or control diet and injected with the serotonin agonist 5-MeODMT (5-methoxy-N, N-dimethyltryptamine). Lithium enhanced the total serotonin syndrome score and particularly flat posture and tremor. Inositol, but not forskolin, mitigated the effects of lithium. Inositol was also injected in the lateral ventricle of rats pretreated with chronic dietary lithium or regular rat chow for 3 weeks and injected with carbidopa and L-
5-hydroxytryptophan
(
5-HTP
). Lithium attenuated wet dog shakes, but inositol had no significant effect on lithium-treated or control rats. These findings suggest that the enhancement of the serotonin syndrome by lithium may be related to lithium-induced inositol depletion.
...
PMID:Myo-inositol attenuates the enhancement of the serotonin syndrome by lithium. 761 10
The effects of conditioned fear stress (CFS), an animal model of anxiety, on brain dopamine (DA) and serotonin (5-HT) metabolism and behavior were investigated in rats. CFS (exposure to an environment paired previously with footshock) after single footshock stress increased plasma corticosterone levels and defecation, and induced freezing behavior. It also increased 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the medial prefrontal cortex (mPFC), paraventricular nucleus of the hypothalamus (PVH) and lateral hypothalamus, increased homovanillic acid (HVA) levels in the mPFC and amygdala, and increased 5-hydroxyindoleacetic acid (5-HIAA) level in the mPFC. Rats exposed to the stress for 10 days displayed enhanced freezing induced by CFS compared to rats given only one footshock session, according to the augmentation of fear. CFS after repeated footshock increased DOPAC levels in all seven brain regions and HVA levels in the mPFC, nucleus accumbens, amygdala and hippocampus. It also increased 5-HIAA levels in the mPFC and PVH. Thus, it was deduced that CFS after repeated footshock activated DA and 5-HT metabolism not only in the mPFC but also in other various brain regions, whereas increased metabolism of both DA and 5-HT was marked in the mPFC after CFS following a single footshock. In behavioral pharmacological experiments, the effects of various serotonergic agents and diazepam on CFS-induced freezing behavior were examined. The benzodiazepine diazepam (1mg/kg) and the selective
5-HT1A
agonist ipsapirone (0.5-10mg/kg) significantly reduced freezing. The augmentation of 5-HT activity by the 5-HT precursor (L-
5-HTP
) and the selective 5-HT reuptake inhibitor (citalopram) also attenuated freezing. The 5-HT synthesis inhibitor PCPA failed to change freezing. In conclusion, these results suggest that the anxiolytic effect of ipsapirone results from the activation of postsynaptic
5-HT1A
receptors and the facilitation of 5-HT neurotransmission decreases anxiety. This model may be useful for detecting the anxiolytic potential for drugs and examining the relationship of 5-HT to anxiety.
...
PMID:[Effects of conditioned fear stress on monoaminergic systems in the rat brain]. 768 27
The potential
5-HT1A
antagonist properties of the beta-antagonist tertatolol were assessed using biochemical and electrophysiological assays in the rat. (+/-) Tertatolol bound with high affinity (Ki = 38 nM) to
5-HT1A
sites labelled by [3H]8-OH-DPAT in hippocampal membranes. The (-)stereoisomer (Ki = 18 nM) was about 50-fold more potent than the (+)stereoisomer (Ki = 864 nM) to inhibit the specific binding of [3H]-8-OH-DPAT. As expected of a
5-HT1A
antagonist, (-)tertatolol prevented in a concentration-dependent manner (Ki = 24 nM) the inhibitory effect of 8-OH-DPAT on forskolin-stimulated adenylate cyclase activity in rat hippocampal homogenates. Furthermore in vivo pretreatment with (-)tertatolol (5 mg/kg s.c.) significantly reduced the inhibitory influence of 8-OH-DPAT (0.3 mg/kg s.c.) on the accumulation of
5-hydroxytryptophan
in various brain areas after the blockade of aromatic L-amino acid decarboxylase by NSD-1015 (100 mg/kg i.p.). In vitro (in brainstem slices; Ki approximately 50 nM) and in vivo (in chloral hydrate anaesthetized rats; ID50 approximately 0.40 mg/kg i.v.), (-)tertatolol prevented the inhibitory effects of the
5-HT1A
receptor agonists 8-OH-DPAT, ipsapirone and lesopitron on the firing rate of serotoninergic neurones within the dorsal raphe nucleus. In about 25% of these neurones, the basal firing rate was significantly increased by (-)tertatolol (up to +47% in vitro, and +30% in vivo). These data indicate that (-)tertatolol is a potent competitive antagonist at both pre (in the dorsal raphe nucleus)-and post (in the hippocampus)-synaptic
5-HT1A
receptors in the rat brain.
...
PMID:(-)Tertatolol is a potent antagonist at pre- and postsynaptic serotonin 5-HT1A receptors in the rat brain. 768 33
The two diphenylbutylpiperazinepyridinyl derivatives, FG5865 and FG5893, have a unique receptor binding profile in that they show very high and essentially equipotent affinities for both
5-HT1A
and 5-HT2 receptors. The present report describes the acute effects of FG5865 and FG5893 on presynaptic 5-hydroxytryptamine (5-HT) neuronal function in the rat CNS, using established ex vivo and in vivo neurochemical techniques. Post-mortem measurements of tissue levels of 5-HT, its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), and of the formation of
5-hydroxytryptophan
(
5-HTP
; after inhibition of aromatic amino acid decarboxylase by NSD 1015) showed that FG5865 (0.1-20 mg/kg, s.c.) and FG5893 (0.1-20 mg/kg, s.c.) dose dependently decreased the synthesis and the metabolism/turnover of 5-HT--this to an extent comparable to the reference
5-HT1A
receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin. Reserpine (5 mg/kg, s.c.) pretreatment did not prevent the FG5893-induced decrease of 5-HT synthesis rate. In contrast, about 25-50 times higher doses of FG5865 were required to produce a comparable decrease in brain 5-HT synthesis in reserpinized vs. non-pretreated rats. In in vivo microdialysis experiments, both FG5865 (0.1-3.0 mg/kg, s.c.) and FG5893 (0.03-1.0 mg/kg, s.c.) caused a marked and dose-dependent decrease of 5-HT release in the ventral hippocampus. Pretreatment with the
5-HT1A
receptor antagonist, (+/-)-pindolol (8 mg/kg, s.c.), abolished the FG5865 (0.3 mg/kg, s.c.)-induced reduction of 5-HT release, and (-)-pindolol (8 mg/kg, s.c.) similarly reversed the FG5893 (0.3 mg/kg, s.c.)-induced decrease. Local infusion of FG5865 into the ventral hippocampus (10 microM, 20-min pulse) resulted in a rapid and transient elevation of the 5-HT output, an effect that was independent of extracellular Ca2+. FG5893, on the other hand, did not affect the 5-HT release upon local administration. The results demonstrate that FG5865 and FG5893 potently affect a range of neurochemical indices of rat brain 5-HT neuronal activity in vivo, in a way consistent with indirect (FG5865) and direct (FG5865 and FG5893) stimulation of the
5-HT1A
autoreceptors in the raphe nuclei.
...
PMID:5-HT1A autoreceptor-mediated effects of the amperozide congeners, FG5865 and FG5893, on rat brain 5-hydroxytryptamine neurochemistry in vivo. 769 22
The effects of the novel antidepressant tianeptine on behaviours induced by the serotonin (5-HT) precursor
5-hydroxytryptophan
(
5-HTP
) and the
5-HT1A
agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) were investigated. Tianeptine (10 mg/kg, i.p.) significantly attenuated wet dog shakes (WDS) induced by
5-HTP
(75 mg/kg, i.p.; 30 min after carbidopa 25 mg/kg, i.p.). The effect was most marked when
5-HTP
and tianeptine were given together. The main metabolite of tianeptine also attenuated WDS. Components of the 5-HT syndrome (i.e. reciprocal forepaw treading, hind limb abduction, flat body posture) induced by 8-OH-DPAT (0.5 mg/kg, s.c.) were unaffected by tianeptine and
5-HTP
given both singly or together. However, tianeptine significantly reduced faecal pellet formation but not cage crossings resulting from 8-OH-DPAT administration. These cage crossings but not the associated faecal pellet formation were reduced by
5-HTP
. This reduction was prevented by tianeptine. The increase of extracellular 5-HT in the frontal cortex following administration of
5-HTP
was opposed and the concurrent increase of extracellular 5-hydroxyindoleacetic acid (5-HIAA) was enhanced by tianeptine. The above behavioural and neurochemical findings indicate that tianeptine opposes the increase of 5-HT at receptor sites due to
5-HTP
administration.
...
PMID:Behavioural and neurochemical evidence for the decrease of brain extracellular 5-HT by the antidepressant drug tianeptine. 769 70
The inhibitory potencies of selective serotonin (5-hydroxytryptamine, 5-HT) uptake inhibitors on isolation-induced aggressive behaviour in male mice were studied. Furthermore, the role of postsynaptic
5-HT1A
receptors in the mediation of aggressive behaviour was studied. The selective 5-HT uptake inhibitors, sertraline, floxetine, femoxetine and fluvoxamine, showed weak antiaggressive effects, and citalopram and paroxetine were ineffective. This rank of potencies corresponded with neither uptake inhibitory potencies in vitro nor potentiation of 1-
5-hydroxytryptophan
(1,
5-HTP
)-induced motor effects in vivo, as citalopram and paroxetine were among the most potent compounds in these tests. A subeffective dose of 1,
5-HTP
(110 mumol/kg = 25 mg/kg, s.c.) potentiated the antiaggressive effect of citalopram and paroxetine more than 110 and 1600 times, respectively. The effects of sertraline, fluvoxamine, fluoxetine and femoxetine were only potentiated 3, 36, 4 and 16 times, respectively. The 5-HT releasing compound fenfluramine inhibited the aggressive behaviour dose dependently, and depletion of 5-HT by treatment with p-chloro-phenylalanine methyl ester attenuated this effect significantly. p-Chloro-phenylalanine methyl ester was ineffective itself, but potentiated the antiaggressive effect of the
5-HT1A
receptor agonist, 8-hydroxy-2-(di-n-propylamin)tetralin (8-OH-DPAT). The beta-adrenoceptor/
5-HT1A
receptor antagonist, (-)-penbutolol, reversed the antiaggressive effects of 8-OHDPAT. In conclusion, selective 5-HT uptake inhibitors act in different ways on isolation-induced aggressive behaviour, and postsynaptic
5-HT1A
receptors are involved in mediating the aggressive behaviour.
...
PMID:Isolation-induced aggression in mice: effects of 5-hydroxytryptamine uptake inhibitors and involvement of postsynaptic 5-HT1A receptors. 769 61
Hippocampal rhythmical slow activity (RSA) can be elicited by stimulation of the midbrain reticular formation. Buspirone, chlordiazepoxide and imipramine are all anxiolytic and have all been shown to decrease the frequency of RSA. All these compounds have been suggested to affect, directly or indirectly, 5-HT metabolism and function. The present experiments tested the possibility that buspirone, chlordiazepoxide and imipramine reduce RSA frequency via
5-HT1A
autoreceptors. Rats received buspirone (10 mg/kg), chlordiazepoxide (5 mg/kg) and imipramine (30 mg/kg) after 5-HT depletion with p-chlorophenylalanine (pCPA, 100 mg/kg/day for 3 days or 350 mg/kg/day for 2 days) or after pretreatment with
5-HTP
(40 mg/kg, to replete 5-HT) as well as pCPA. The frequency-reducing effects produced by buspirone and chlordiazepoxide were unchanged by either dose of pCPA, whereas the frequency-reducing effect of imipramine was completely eliminated by the high dose of pCPA. Pindolol, but not beta-blockers (a combination of metoprolol and ICI118,551), was able to block the effect of imipramine on RSA frequency. Pindolol has been reported to block the effects of buspirone but not chlordiazepoxide. These data suggest that: (1) buspirone obtains its frequency-reducing effects via pre- or post-synaptic
5-HT1A
receptors rather than
5-HT1A
autoreceptors; (2) chlordiazepoxide obtains its frequency-reducing effect via benzodiazepine receptors and GABA with no direct or indirect involvement of 5-HT systems; and (3) imipramine obtains its frequency-reducing effect by increasing the availability of 5-HT at
5-HT1A
receptors which are not autoreceptors.
...
PMID:The interaction of serotonin depletion with anxiolytics and antidepressants on reticular-elicited hippocampal RSA. 776 Sep 82
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