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)

Effects of long-term feeding with tryptophan (TRP)-free diet on the free running periods of wheel-running rhythm and the central serotonergic neurotransmission were examined in male blinded rats. Long-term feeding with TRP-free diet did not change the periods of wheel-running rhythm calculated from chi 2 periodogram but disordered its pattern, which seemed to be due to masking or entrainment effects. On the other hand, long-term TRP-free diet decreased the concentrations of TRP, 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in all brain regions tested; frontal cortex, hippocampus, thalamus, hypothalamus and pons. The density of 5-HT1A receptor (3H-8-OH-DPAT) binding was significantly decreased in only frontal cortex, while no significant change was observed in the density of 5-HT2 receptor (3H-ketanserin) binding in all regions. Although the mechanism of down-regulation of 5-HT1A receptor in frontal cortex is obscure, it was confirmed that TRP-free diet decreased central 5-HT synthesis and 5-HT neurotransmission. This dysfunction of 5-HT neurotransmission by TRP-free diet is suggested to make the circadian rhythm pacemaker susceptible to subtle environmental factors by lowering its intensity.
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PMID:[Effect of long-term feeding with tryptophan-free diet on the circadian rhythm in rats]. 127 10

Pigeon cerebrospinal fluid was assayed for 5-HT (5-hydroxytryptamine) and catecholamine metabolites after systemic drug injection. The 5-HT1-like receptor agonists 8-hydroxy-(di-n-propylamino)tetralin (8-OH-DPAT), 5-methoxy-3(1,2,3,6-tetrahydropyridin-4-yl)1H indole (RU 24969), 1-(m-trifluoromethylphenyl)piperazine (TFMPP), and 1-(3-chlorphenyl)piperazine (mCPP) decreased levels of the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA) without altering other metabolites. 5-HIAA decreases occurred at doses of 8-OH-DPAT and RU 24969 that have anti-conflict effects in pigeons, whereas TFMPP and mCPP decreased 5-HIAA only at behaviorally disruptive doses. The novel compound 1-(2-methoxyphenyl)-1-(4-(2-phthalimido)butyl)piperazine (NAN-190), a putative 5-HT1A receptor antagonist, did not affect 5-HIAA, but attenuated the decreases produced by the agonists. NAN-190 and the alpha 1-adrenoceptor antagonist prazosin increased levels of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol and had additive effects when co-administered. The rank order of potency in inhibiting [3H]8-OH-DPAT binding in pigeon cerebrum was 8-OH-DPAT = RU 24969 > NAN-190 >> mCPP > TFMPP. The results support suggestions that decreased 5-HT neurotransmission underlies the anxiolytic-like effects of 5-HT1A receptor agonists in pigeons.
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PMID:Neurochemical effects of 5-HT1 receptor ligands in pigeons. 128 73

One of the proposed mechanisms of action for the anxiolytic effects of the benzodiazepines is via a decrease in central serotonergic neurotransmission. The aim of this study was to combine in vivo microdialysis in the rat with behaviour on the elevated X-maze to determine changes in 5-HT release in the ventral hippocampus with concomitant measurement of behaviour. Twenty minutes exposure to the elevated X-maze resulted in an increase in extracellular 5-HT in the ventral hippocampus with no change in extracellular 5-HIAA. Restricting the rat to either the open or the closed arms produced an increase in extracellular 5-HT, however the increase in 5-HT when restricted to the open arms was not significantly greater than that on the closed arms. Forty minutes pretreatment with diazepam (2.5 mg kg-1 IP) significantly inhibited the increase in extracellular 5-HT in the ventral hippocampus and had an anxiolytic profile over 5 min and 20 min exposures of the rats to the X-maze. Diazepam had no effect on basal 5-HT levels before exposure to the X-maze but reduced extracellular 5-HT levels when the animal was returned to the holding cage. Forty minutes pretreatment with the .5-HT1A receptor partial agonist ipsapirone (1 mg kg-1 IP) significantly inhibited the increase in extracellular 5-HT in the ventral hippocampus but did not produce behaviour different from vehicle controls after 5 or 20 min periods on the X-maze.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of established and putative anxiolytics on extracellular 5-HT and 5-HIAA in the ventral hippocampus of rats during behaviour on the elevated X-maze. 128 16

The pharmacological profile of DV-7028, a pyrido triazine derivative, showed that it is a potent and selective 5-hydroxytryptamine (5-HT)2 receptor antagonist. DV-7028 bound to 5-HT2 receptors in rat brain membranes with a Ki value of 22 nM and caused shifts to the right of the concentration-contraction curves to 5-HT in rat thoracic aorta and canine femoral arteries, which are attributed to activation of 5-HT2 receptors. The compound was highly active by oral administration (0.1-10 mg/kg) based on blockade of the 5-HT-induced pressor responses in pithed rats. In contrast, DV-7028 had no affinity for 5-HT1A, 5-HT1B and 5-HT1D receptors. The affinity of the compound was 14-26 times greater for the 5-HT2 receptors when compared to 5-HT1C, adrenergic alpha 1, dopamine D2 and histamine H1 receptors. In human platelets, DV-7028 attenuated the aggregation induced by collagen and inhibited the amplifying effect of 5-HT with collagen on platelet aggregation. Furthermore, a 10-day toxicity study revealed that DV-7028 was a safe compound which did not produce lethality at repeated oral doses of 800 mg/kg/day in rats. These results indicate that DV-7028 is a selective and potent 5-HT2 receptor antagonist which is orally active and safe.
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PMID:Pharmacological profile of a new 5-hydroxytryptamine2 receptor antagonist, DV-7028. 128 70

In cerebral cortex and lateral septal nuclei different serotonergic receptor subtypes coexist, thus a different action on neuronal firing may be expected depending on the receptor activated. Dorsal raphe nucleus stimulation produced an increased rate of firing in cortical layer V, and in lateral septal nuclei. However, firing rate in cortical layer VI remained unchanged after stimulating the dorsal raphe nucleus. Clomipramine is a tricyclic which exerts its main actions on serotonergic receptors, and long-term treatment with this antidepressant produced a selective increased firing rate in lateral septal neurons, but not in cortical neurons. From an electrophysiological point of view, it is concluded that the excitatory actions on firing rate elicited by dorsal raphe nucleus stimulation or clomipramine treatment are mediated by 5-HT2 receptor subtype activation which is likely to be acting as a 5-HT1A modulator in such places where both receptor subtypes coexist.
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PMID:Cortical and septal responses to dorsal raphe nucleus stimulation in the rat: long-term clomipramine actions. 129 70

The synthesis and the 5-HT1A and 5-HT2 receptor affinity of 2-substituted 1-[3-(4-aryl-1-piperazinyl)propyl]-imidazoles (1-8) has been described. It has been shown that both the N-3 imidazole atom and the N-1 piperazine one should be considered as possible protonation centers under physiological conditions. It has been found that the folded conformations of 1-8 exist predominantly in solution. Moreover, three different modes of interaction of the analyzed compounds with 5-HT1A and 5-HT2 receptor sites have been proposed.
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PMID:Structure-activity relationship studies of CNS agents. Part VII. The effect of the imidazole fragment in 2-substituted 1-[3-(4-aryl-1-piperazinyl)propyl]imidazoles on their interaction modes with 5-HT1A and 5-HT2 receptors. 129 15

The effects of levoprotiline (LEV), a (-)-enantiomer of oxaprotiline (OXA) and a clinically effective antidepressant, on the binding parameters of hippocampal 5-HT1A and cortical 5-HT2 receptors of rats were compared with those of (+)-enantiomer of OXA ((+)-OXA), imipramine and mianserin. Both LEV and (+)-OXA displayed in vitro some affinity for 5-HT1A receptors labelled with [3H]-8-OH-DPAT, and for 5-HT2 receptors labelled with [3H]-ketanserin. Repeated administration of LEV, for 14 days led to a marked increase in the number of 5-HT1A binding sites in the rat hippocampus, with no change in the KD values. (+)-OXA, imipramine and mianserin produced similar effects on 5-HT1A binding parameters. The number of 5-HT2 receptors was increased after two weeks of LEV administration, not altered after (+)-OXA, and decreased after imipramine or mianserin. The number of [3H]-ketanserin binding sites was decreased after four weeks of (+)-OXA administration, but not altered after LEV. The specific binding of [3H]-ketanserin in the rat cerebral cortex was decreased after repeated treatment with LEV and (+)-OXA (ex vivo). In competition studies the affinity of serotonin for [3H]-ketanserin binding sites was decreased in LEV- and increased in (+)-OXA-treated rats. The results suggest that LEV similarly to other antidepressants increases the number of 5-HT1A receptors, however without common alteration in 5-HT2 receptor number and function.
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PMID:Changes in the rat brain 5-HT1A and 5-HT2 receptors after chronic administration of levoprotiline, (+)-oxaprotiline and other antidepressant drugs. 130 56

The effect of a steric hindrance around the protonation center of the model 4-substituted 1-(3-chlorophenyl)-piperazines 1-9 and 11-14 on their affinity for 5-HT1A and 5-HT2 receptor sites was investigated. Additional evidence for hydrophobic interactions between the N-4 hydrocarbon substituents and 5-HT1A receptors has been presented. However, the hydrophobic forces play a minor role in stabilization of the bioactive complex with 5-HT2 receptors. It has also been found that even bulky substituents around the protonation center of 1-aryl-piperazines are well tolerated at both 5-HT1A and 5-HT2 sites.
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PMID:Structure-activity relationship studies of CNS agents. Part VIII. Bulk tolerance around the protonation center of 4-substituted 1-(3-chlorophenyl)piperazines at 5-HT1A and 5-HT2 receptors. 130 59

5-hydroxytryptamine (5-HT) is a mitogen for fibroblasts, vascular smooth muscle cells, renal mesangial cells, and jejunal crypt cells. The human carcinoid cell line (termed BON) that we established in our laboratory from a pancreatic carcinoid tumor produces and secretes 5-HT. In this study, therefore, we examined the effect of 5-HT on growth of BON cells. Furthermore, by use of selective 5-HT receptor antagonists, we examined receptor and post-receptor mechanisms by which 5-HT-induced responses were produced. 5-HT stimulated growth of BON cells. 5-HT stimulated phosphatidylinositol (PI) hydrolysis in a dose-dependent fashion and inhibited cyclic AMP production in a dose-dependent fashion. The 5-HT1A/1B receptor antagonist, SDZ 21-009, prevented the reduction of cyclic AMP production evoked by 5-HT and inhibited the mitogenic action of 5-HT. The 5-HT1C/2 receptor antagonist, mesulergine, competitively inhibited PI hydrolysis, but did not affect the mitogenic action of 5-HT. The mitogenic action of 5-HT and the reduction of cyclic AMP production evoked by 5-HT were also inhibited by pertussis toxin. These results suggest that 5-HT is an autocrine growth factor for BON cells and that mitogenic mechanism of 5-HT involves receptor-mediated inhibition of the production of cyclic AMP which may be linked to pertussis toxin-sensitive GTP binding protein. 8-bromo-cyclic AMP inhibited growth of BON cells whereas 8-bromo-cyclic GMP had no effect on cell growth. Involvement of protein kinase A in BON cell growth regulation was confirmed by the observation that a cAMP-dependent protein kinase antagonist (Rp-cAMPS) could stimulate BON cell growth.
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PMID:Receptor-mediated autocrine growth-stimulatory effect of 5-hydroxytryptamine on cultured human pancreatic carcinoid cells. 130 21

The cholecystokinin (CCK) family of peptides and their receptors are widely distributed throughout the gastrointestinal and central nervous systems where they regulate secretion, motility, growth, anxiety, and satiety. The CCK receptors can be subdivided into at least two subtypes, CCKA and CCKB on the basis of pharmacological studies. We report here the purification of the CCKA receptor to homogeneity from rat pancreas by using ion-exchange and multiple affinity chromatographic separations. This allowed partial peptide sequencing after chemical/enzymatic cleavage and synthesis of degenerate oligonucleotide primers. These primers were used for initial cloning of the cDNA from rat pancreas by PCR. The predicted protein sequence of the cDNA clone contained the five partial peptide sequences obtained from the purified protein. Seven putative transmembrane domains suggest its membership in the guanine nucleotide-binding regulatory protein-coupled receptor superfamily. In vitro transcripts of the cDNA clone were functionally expressed in Xenopus oocytes and displayed the expected agonist and antagonist specificity.
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PMID:Purification, molecular cloning, and functional expression of the cholecystokinin receptor from rat pancreas. 131 82


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