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)

Adenylate cyclase activity was measured in platelet membranes from 10 healthy controls, 12 depressed patients, and the same patients after treatment with clomipramine (CMI) followed by lithium carbonate (Li) supplementation, in an attempt to determine whether any evidence for an effect on the serotonergic system could be obtained in peripheral cells. There were no differences in basal, NaF-, PGE1-, or forskolin-stimulated activity either between the control subjects and depressed patients or between activities in the patients measured before treatment, after CMI, and after CMI+Li. The degree of inhibition of forskolin-stimulated adenylate cyclase by 5-HT, an effect putatively mediated by a 5-HT1A-like receptor, was not different in the depressed patients compared to controls or affected by CMI treatment, but was significantly reduced after Li supplementation.
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PMID:Platelet adenylate cyclase activity in depression and after clomipramine and lithium treatment: relation to serotonergic function. 136 62

TFMPP and m-CPP, non-selective 5-HT agonists, administered in doses of 1-20 mg/kg evoked hyperthermia in rats at a high ambient temperature (28 degrees C). The hyperthermic effect of TFMPP (10 mg/kg) or m-CPP (10 mg/kg) was dose-dependently antagonized by the 5-HT1c and 5-HT2 receptor antagonists mesulergine (0.5-4 mg/kg), ketanserin (0.6-2.5 mg/kg) and ritanserin (0.5-2 mg/kg) and by the non-selective 5-HT antagonist metergoline (0.5-1 mg/kg), or was attenuated by the 5-HT1A, 5-HT2 and dopamine receptor antagonist spiperone (3 mg/kg, but not 0.3 or 1 mg/kg). On the other hand, the 5-HT1A, 5-HT1B and beta adrenoceptor antagonists pindolol (2 mg/kg) and cyanopindolol (2 mg/kg), the 5-HT1A receptor agonist/antagonist ipsapirone (10 and 35 mg/kg) and haloperidol (0.25 and 0.5 mg/kg) showed a tendency towards enhancing the TFMPP- or m-CPP-induced hyperthermia. The 5-HT1A and alpha 1-adrenoceptor antagonist NAN-190 (1-4 mg/kg), the 5-HT3 antagonists tropisetron (0.01-1 mg/kg) and zacopride (0.5 and 1 mg/kg), the beta-blockers betaxolol (8 mg/kg) and ICI 118, 551 (8 mg/kg), which have no affinity for 5-HT receptors and prazosin (1 mg/kg), did not affect the hyperthermic effect of TFMPP or m-CPP. The hyperthermias studied were not modified, in animals with 5-HT lesion produced by p-chloroamphetamine (PCA) either. All the drugs used as putative receptor antagonists, as well as PCA, did not change or decreased (ipsapirone) the body temperature in heat-adapted rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hyperthermia induced by m-trifluoromethylphenylpiperazine (TFMPP) or m-chlorophenylpiperazine (m-CPP) in heat-adapted rats. 136 64

Early passaged bovine pulmonary artery smooth muscle cells (SMC) respond to serotonin (5-HT) by developing a reversible change in configuration. (Lee et al. J. Cell. Physiol. 138:145, 1989). This configurational change does not occur in pulmonary artery endothelial cells (EC) subjected to 5-HT and is adenosine triphosphate (ATP) dependent, lost with passage of SMC, and inhibited by various agents that block high-affinity 5-HT uptake. We now report a second configurational change (also dendritic formation) of SMC produced by 5-HT only in the presence of isobutylmethylxanthine (IBMX), an inhibitor of phosphodiesterase. This configurational change was also ATP dependent, but unlike the first response, (Lee et al., 1989), it occurred in both first and later passaged SMC and was not inhibited by blockade of 5-HT uptake. Also, unlike the response with 5-HT alone that failed to elevate cAMP, this one was associated with a large elevation of cAMP (eight fold above control values), similar to the response to the beta-agonist isoproterenol, plus IBMX. The second response was not blocked by a variety of 5-HT receptor antagonists but was reproduced by (+/-)-8-hydroxy-DPAT HBr (8-OH-DPAT), a reputed 5-HT1A agonist. The response was not dependent upon Ca2+ and was blocked by 1-2 mM n-phenylanthranilic acid or anthracene-9-carboxylic acid, electrically conductive Cl- channel inhibitors. Hence, 5-HT in the presence of IBMX causes a marked elevation of cAMP of SMC and this elevation in cAMP likely results in a cellular configurational change through a Cl- channel-dependent mechanism similar to that we previously described for EC in the presence of beta-adrenergic agonist stimulation (Ueda et al. Circ. Res. 66:951, 1990). EC do not show a similar response to 5-HT possibly because cAMP is not adequately elevated, even in the presence of IBMX, to enhance Cl- channel activity. We propose that our observations indicate the presence of two sites of action of 5-HT on the smooth muscle cell, one intracellularly and another at a cell surface receptor.
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PMID:Serotonin produces a configurational change of cultured smooth muscle cells that is associated with elevation of intracellular cAMP. 137 Aug 41

In vivo voltammetry with carbon fibre electrodes was used to study the effect of the serotoninergic (5-HT) neuronal system on the noradrenergic (NE) system in the Locus coeruleus of the rat. The voltammetric DOPAC signal in the Locus coeruleus, used as a measure of NE neuronal activity, was increased after systemic application of the 5-HT1B agonist CGS-12066B, the 5-HT2 antagonist ritanserin, and, to a lesser extent, by ipsapirone, a 5-HT1A agonist. The findings suggest that the NE neuronal system of the Locus coeruleus is stimulated by 5-HT1A and 5-HT1B receptor activation and inhibited by 5-HT2 receptors. Likewise the 5-HT releaser and uptake inhibitor fenfluramine increased the DOPAC level in the Locus coeruleus. In contrast to the 5-HT1 agonists, which reduced 5-hydroxyindoleacetic acid (5-HIAA) in the Nucleus raphe dorsalis, ritanserin increased the 5-HIAA signal in this nucleus. This finding could help to explain the action of ritanserin as sleep-modulating substance.
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PMID:Serotonin-norepinephrine interactions: a voltammetric study on the effect of serotonin receptor stimulation followed in the N. raphe dorsalis and the Locus coeruleus of the rat. 137 60

Intrathecal (i.th.) administration of substance P (SP, 6.5 nmol) at the Th 8-10 level in conscious rats increased blood pressure (carotid artery), heart rate and plasma catecholamine concentrations. The responses were antagonized by the intravenous (i.v.) but not i.th. pretreatment with the 5-HT2-receptor antagonists ketanserin and ritanserin and intrathecally administered serotonin (5-HT, 10 micrograms). The pressor response and the increase in plasma noradrenaline concentrations were also antagonized by i.v. or i.th. pretreatment with the 5-HT1A-agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT). In contrast the pressor response to SP was facilitated by the 5-HT1A-antagonist 1-pindolol (i.v. or i.th). Pretreatment with SP (i.th) reduced the hypotensive response to i.v. 8-OH-DPAT. These results demonstrate functional interactions between SP and serotonergic mechanisms in the central system, but the precise location and nature were not elucidated.
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PMID:Cardiovascular effects of intrathecal administration of substance P in the rat: interactions with serotonergic mechanisms. 137 13

Depression is a heterogeneous disease state characterised by complex alterations in several CNS neurotransmitter and receptor systems. All antidepressants are thought to act by causing postsynaptic adaptive changes (e.g. in transducers or second messengers) within these systems. Thus, the mechanism of action of selective serotonin reuptake inhibitors (SSRIs) cannot simply be explained in terms of inhibition of serotonin (5-hydroxytryptamine) [5-HT] reuptake. Fluvoxamine, sertraline and fluoxetine downregulate central beta-adrenoceptors, and all SSRIs are believed to normalise central 5-HT1A- and 5-HT2-receptor density and function in patients with depression. SSRIs are as effective as tricyclic antidepressants in the treatment of depression, but have distinct tolerability advantages--they are not associated with anticholinergic adverse effects, cardiotoxicity, sedation or weight gain. However, gastrointestinal reactions (e.g. nausea, diarrhoea/loose stools, constipation) are relatively common during SSRI therapy. Additionally, in contrast to tricyclic antidepressants, SSRI dosage adjustments appear to be unnecessary in elderly depressed patients. Fluvoxamine has a much shorter elimination half-life than fluoxetine and its active metabolite, norfluoxetine, and therefore a reduced potential for drug interactions. Only small amounts of fluvoxamine and fluoxetine, but large quantities of paroxetine, are secreted in breast milk. Furthermore, genetic polymorphism has not been documented for fluvoxamine metabolism, whereas slow and fast metabolisers of paroxetine, and fast metabolisers of fluoxetine have been identified. SSRIs have a better tolerability profile than tricyclic antidepressants, as indicated by lower mean rank scores for behavioural toxicity. Moreover, SSRIs are associated with a much lower incidence of fatal toxicity than tricyclics, and appear to be relatively safe in overdosage.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pharmacological differences of serotonin reuptake inhibitors and possible clinical relevance. 137 71

We have previously demonstrated that susceptibility of the Lewis rat to inflammatory disease, compared with the relatively resistant Fischer F344/N rat, is related to a hyporesponsive hypothalamopituitary-adrenal axis to inflammatory and other stress mediators. Because serotonin (5-HT) and the 5-HT1A receptor are important stimulators of this axis, we have investigated the levels of 8-[3H]-hydroxy-2,3-(di-n-propylamino)tetralin binding sites, 5-HT1A mRNA, 5-HT, and 5-hydroxyindoleacetic acid in various brain regions of Lewis, outbred Harlan Sprague Dawley, and Fischer F344/N rats. Lewis rats expressed significantly fewer hippocampal and frontal cortical 8-[3H]-hydroxy-2,3-(di-n-propylamino)tetralin binding sites and less 5-HT1A mRNA than Harlan Sprague Dawley and Fischer F344/N rats. Adrenalectomy increased the number of 8-[3H]hydroxy-2,3-(di-n-propylamino)tetralin binding sites and 5-HT1A mRNA expression in the hippocampus of all three strains. Levels of hippocampal 5-HT in Fischer F344/N rats were significantly greater than levels detected in the same regions from Lewis and Harlan Sprague Dawley rats. Hypothalamic 5-HT and 5-hydroxyindoleacetic acid levels in Harlan Sprague Dawley rats were higher than the same area from the other two strains. Adrenalectomy increased the levels of 5-hydroxyindoleacetic acid in the hypothalamus of all three strains. We conclude that hippocampal 5-HT1A receptor densities and 5-HT levels in the rat parallel the activity and responsiveness of the hypothalamopituitary-adrenal axis.
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PMID:Hippocampal 8-[3H]hydroxy-2-(di-n-propylamino) tetralin binding site densities, serotonin receptor (5-HT1A) messenger ribonucleic acid abundance, and serotonin levels parallel the activity of the hypothalamopituitary-adrenal axis in rat. 137 29

Repeated cocaine intoxication can result in the development of behavioral sensitization in animals and psychosis in humans, phenomena that have been associated with alterations in dopamine (DA) function. Using electrophysiologic and autoradiographic techniques, modifications of central serotonin (5-hydroxytryptamine; 5-HT) systems were investigated in rats treated with a regimen of cocaine administration that produced behavioral sensitization. The inhibitory response of single 5-HT neurons in the dorsal raphe (DR) to (-)-cocaine, the 5-HT uptake inhibitor fluoxetine or the 5-HT1A agonist 8-hydroxy-2-[di-N-propylamino]tetralin (8-OHDPAT) was significantly enhanced in cocaine-treated rats. Furthermore, several brain areas that contain either cell bodies (DR) or terminals for 5-HT (medial and sulcal prefrontal cortex, frontal cortex) showed cocaine-induced elevations in [3H]imipramine-labeled 5-HT uptake sites, while [3H]-8-OHDPAT-labeled 5-HT1A receptors were decreased only in the central medial amygdala. These results suggest that modifications of autoregulatory mechanisms secondary to alterations of 5-HT uptake processes may contribute to the development of cocaine sensitization.
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PMID:Chronic cocaine enhances serotonin autoregulation and serotonin uptake binding. 138 62

To study the regulation of 5-HT1A receptors in the brainstem, the region most relevant to the serotonin syndrome and to serotonin-responsive human myoclonic disorders, we chronically treated rats with various 5-HT1A agonists and labeled 5-HT1A sites with [3H]8-OH-DPAT. Daily injection for 30 consecutive days of 10 mg/kg ip 8-OH-DPAT (pre- and post-synaptic 5-HT1A agonist) significantly decreased 8-OH-DPAT-evoked flat body posture, forelimb myoclonus, and hypothermia compared to chronic vehicle injection. There was no cross tolerance to 8-OH-DPAT in rats chronically injected with ipsapirone or buspirone (presynaptic 5-HT1A agonists). However, none of the 5HT1A agonists significantly altered Bmax of brainstem 5-HT1A binding sites. Chronic injection with other drugs such as 1-propranolol, (+/-) pindolol and spiperone (5-HT1A and 5-HT2 antagonists), methysergide (5-HT1 and 5-HT2 antagonist), and agonists and antagonists at various other 5-HT receptors also had no effect on binding parameters. These data demonstrate lack of cross-tolerance between pre- and post-synaptically acting 5-HT1A agonists and absence of down-regulation of presynaptic 5-HT1A sites at doses which induced tolerance of 5-HT1A-mediated behaviors of the serotonin syndrome. They suggest changes in the post-synaptic cell rather than the receptor recognition site as the mechanism of tolerance.
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PMID:Brainstem 5-hydroxytrytamine1A binding sites are not down-regulated by agonists which induce tolerance in the rat: myoclonus and other serotonergic behaviors. 138 64

This study assessed the effects of a serotonin (5-HT)1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT2 agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and a 5-HT2 antagonist ketanserin on fully kindled seizures from the hippocampus. 8-OH-DPAT produced a marked suppression in hippocampal kindled seizures, while producing behavioral signs similar to those seen in the 5-HT syndrome. Although DOI and ketanserin did not affect kindled focal epileptic activity, DOI shortened and ketanserin prolonged the latency to onset of generalized convulsions. Our data suggest that 5-HT1A receptors play an inhibitory role in the generation of hippocampal seizures, whereas 5-HT2 receptors may participate in kindled seizure generalization from this region.
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PMID:Role of serotonin receptor subtype in seizures kindled from the feline hippocampus. 138 98


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