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

5-Hydroxytryptamine (serotonin, 5-HT) is released from the gastrointestinal tract by vagal stimulation. This biogenic amine produces many alterations in gastric functional parameters, including inhibition of gastric acid secretion. This study was designed to characterize the 5-HT receptor subtype modulating gastric acid secretion. In urethane-anesthetized acute gastric fistula rats, systemic 5-HT (3.5 mumol/kg i.v.) inhibited acid output stimulated by pentagastrin infusion by 58%. Close gastric intra-arterial (i.a.) injection of methysergide, methiothepin, metergoline or spiperone but not tropisetron, renzapride or ritanserin was effective in reversing 5-HT-induced inhibition of acid secretion. Close i.a. administration of the potent 5-HT1A/1B antagonist 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine displayed partial agonist properties in this model, but did not antagonize 5-HT-induced inhibition of acid output. In a study of 5-HT agonists given close i.a. to the gastric circulation, 5-HT (0.88 mumol/kg) inhibited acid secretion by 48%. A 3-fold higher dose (2.6 mumol/kg) of the general 5-HT1 agonist, 5-carboxamidotryptamine (5-CT), was needed to inhibit acid secretion significantly. In contrast, neither the selective 5-HT1A agonist (+-)-8-hydroxy-2-(n-dipropylamino)-tetralin nor 5-HT2 agonist (+-)-1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane (0.88 or 2.6 mumol/kg) attenuated gastric acid secretion. Thus, the data suggest that the site mediating inhibition of acid secretion by exogenous 5-HT belongs to the 5-HT1 family, but may not be of the 5-HT1A subtype.
 ...
PMID:Serotonin inhibits gastric acid secretion through a 5-hydroxytryptamine1-like receptor in the rat. 793 63

A 3-D model of the human 5-HT1a receptor was constructed from its amino acid sequence by computer graphics techniques, molecular mechanics calculations and molecular dynamics simulations. The model has seven alpha-helical membrane spanning segments, which form a central core containing a putative ligand binding site. Electrostatic potentials 1.4 A outside the water accessible surface were mainly negative on the synaptic side of the receptor model and at the postulated ligand binding site, and positive in the cytoplasmic domains. The negative electrostatic potentials around the synaptic domains indicate that positively charged ligands are attracted to the receptor by electrostatic forces. Molecular dynamics simulations of the receptor model with serotonin, ipsapirone, R(-)-methiothepin or S(+)-methiothepin in the central core suggested that up to 22 different amino acid residues may form a ligand binding pocket, and contribute to the specificity of ligand recognition and binding.
 ...
PMID:Molecular dynamics of the 5-HT1a receptor and ligands. 824 92

1. The effects of the 5-HT2A/2C agonist DOB, the selective 5-HT1A agonist NDO 008 (3-dipropylamino-5-hydroxychroman), and the two enantiomers of the selective 5-HT1A agonist 8-OH-DPAT (R(+)-8-OH-DPAT and S(-)-8-OH-DPAT) were studied in a step-through passive avoidance (PA) test in the male rat. 2. The 5-HT1A agonists injected prior to training (conditioning) produced a dose-dependent impairment of PA retention when examined 24 h later. R(+)-8-OH-DPAT was four times more effective than S(-)-8-OH-DPAT to cause an impairment of PA retention. Both NDO 008 and the two enantiomers of 8-OH-DPAT induced the serotonin syndrome at the dose range that produced inhibition of the PA response, thus, indicating activation of postsynaptic 5-HT1A receptors. 3. Neither NDO 008 nor R(+)-8-OH-DPAT induced head-twitches, a behavioural response attributed to stimulation of postsynaptic 5-HT2A receptors. In contrast, DOB induced head-twitches at the 0.01 mg kg(-1) dose while a 200 times higher dose was required to produce a significant impairment of PA retention. 4. The impairment of PA retention induced by both NDO 008 and R(+)-8-OH-DPAT was fully blocked by the active S(+)- enantiomer of the selective 5-HT1A antagonist WAY 100135 and the mixed 5-HT1A/beta-adrenoceptor antagonist L(-)-alprenolol. In contrast, the mixed 5-HT2A/2C antagonists ketanserin and pirenperone were found to be ineffective. Moreover, the beta2-adrenoceptor antagonist ICI 118551, the beta-antagonist metoprolol as well as the mixed beta-adrenoceptor blocker D(+)-alprenolol all failed to modify the deficit of PA retention by NDO 008 and R(+)-8-OH-DPAT. None of the 5-HT1A or 5-HT2A/2C receptor antagonists tested or the beta-blockers altered PA retention by themselves. 5. A 3 day pretreatment procedure (200+100+100 mg kg(-1)) with the tryptophan hydroxylase inhibitor p-chlorophenylalanine (PCPA) did not alter PA retention and did not prevent the inhibitory action of the 5-HT1A agonists, indicating that their effects on PA do not depend on endogenous 5-HT. 6. The effects of NDO 008 on PA were also studied using a state-dependent learning paradigm. NDO 008 was found to produce a disruption of PA when given either prior to training or retention or both prior to training and retention but it failed to affect PA retention when given immediately after training. .7 These findings indicate that the deficit of passive avoidance retention induced by the 5-HT1A agonists is mainly a result of stimulation of postsynaptic 5-HT1A receptors but not 5-HT2A receptors. The 5-HT1A receptor stimulation appears to interfere with learning processes operating at both acquisition and retrieval.
 ...
PMID:Analysis of the 5-HT1A receptor involvement in passive avoidance in the rat. 980 33