Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. 5-Hydroxytryptamine (5-HT) receptor-mediated contraction of endothelium denuded rabbit middle (MCA) and posterior (PCA) cerebral arteries was characterized by use of selective agonists and antagonists for different 5-HT receptor subtypes. 2. 5-HT and various 5-HT receptor agonists contracted the arteries with the following rank order of potency in MCA: 5-carboxamidotryptamine (5-CT) > 5-HT > 5-methoxytryptamine (5-MeOT) > sumatriptan > alpha-methyl-5-HT (alpha-Me-5-HT) >> 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) and in PCA: 5-CT > 5-HT > sumatriptan > 5-MeOT > alpha-Me-5-HT >> 8-OH-DPAT. With few exceptions, the maximal contractile responses of these agonists were similar to that induced by 5-HT. 3. The selective antagonists of 5-HT2A/2C (ketanserin), 5-HT4 (SDZ 205-557) and 5-HT1A/1B (S-(-)-propranolol) sites were devoid of inhibitory effect on 5-HT-mediated contraction in both MCA and PCA, thus excluding activation of the corresponding receptors. 4. In both arteries, the contraction-response curve to 5-HT was unaffected by the 5-HT3 receptor antagonist, ICS 205-930 (0.01 and 0.1 microM) whilst a small (3 and 6 fold displacement) was seen with MDL 72222 (0.1 and 1 microM). 5. The mixed 5-HT1-like/5-HT2A receptor antagonist, methiothepin (0.001-0.1 microM), was a potent antagonist of 5-HT-induced contractions in both arteries, giving pA2 values of 9.4 +/- 0.7 and 9.6 +/- 0.8 in MCA and PCA, respectively. 6. Rauwolscine (O.1-10 MicroM) and yohimbine (0.3, 3 MicroM) inhibited contractions to 5-HT in a competitive manner, pA2 values of 7.1 +/- 0.6 and 6.7 +/-0.6 were determined for rauwolscine in MCA and PCA,respectively. An apparent pA2 value of 6.9 +/-0.2 was calculated for yohimbine (3 MicroM) in both MCA and PCA.7. In conclusion, these results suggest that the contractile response to 5-HT in rabbit isolated MCA and PCA is predominantly mediated by the 5-HTID receptor subtype, although a small contribution by 5-HT3 receptors cannot be excluded.
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PMID:Mediation by 5-HT1D receptors of 5-hydroxytryptamine-induced contractions of rabbit middle and posterior cerebral arteries. 792 24

The effects of post-training (i.p.) injection of TFMPP, mCPP, DOI or 1-NP in the autoshaping learning task was explored. Furthermore, the post-training effects of these agonists after treatment with the antagonists (+/-)-pindolol, (+/-)-propranolol, NAN-190, ketanserin, ritanserin, mesulergine, MDL-72222 or p-chloroamphetamine (5-HT depleter) were studied. Rats were individually trained with a lever-press response (conditioned response; CR) on the autoshaping task and tested 24 h later. The results showed that the injection of TFMPP (1-10 mg/kg), mCPP (1-10 mg/kg), 1-NP (0.1-1.0 mg/kg) or mesulergine (0.4 mg/kg) decreased the rate of CR, while DOI (0.01-0.1 mg/kg) and ritanserin (0.5 mg/kg) and ketanserin (0.001-0.1 mg/kg) increased it. However, the effect induced by TFMPP was reversed by (+/-)-pindolol, ketanserin, ritanserin and PCA; the mCPP-induced effect was antagonized by (+/-)-propranolol, ketanserin, ritanserin and MDL-72222; and the effect produced by 1-NP was reversed by ketanserin, ritanserin and PCA. In addition, the increment in CR provoked by DOI was enhanced by ketanserin, and reversed by ritanserin, mesulergine and PCA. These findings suggest that TFMPP, 1-NP and DOI exerted their effects via stimulation of presynaptic 5-HT receptors. The effects of mCPP most probably reflect activation of postsynaptic receptors. The present data suggest that both 5-HT1B and 5-HT2A-2C receptors play a significant role in the consolidation of learning.
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PMID:Role of 5-HT1B, 5-HT2A and 5-HT2C receptors in learning. 933 78

We have previously reported that 5-HT1B/1D and 5-HT2A/2B/2C receptors play a role in learning and memory. The present investigation was devoted to analyze further in the autoshaping learning task: (1) the effects of the 5-HT1A/1B/1D receptor agonist, GR46611, the 5-HT1B/1D receptor antagonist, GR127935, and the selective 5-HT2A receptor antagonist, MDL100907. Consistent with a role of 5-HT1B/1D receptors in learning, the post-training injection of GR46611 (1-10 mg/kg) decreased the consolidation of learning whereas GR127935 (10 mg/kg) increased it; the effects of both drugs were reversed by PCA pretreatment. GR127935 abolished the decrease induced by GR46611, TFMPP and mCPP, whereas MDL100907 (0.1-3.0 mg/kg) had no effect by itself but abolished the effects of DOI, ketanserin and TFMPP and moderately inhibited the effects elicited by mCPP, 1-NP and mesulergine. Neither did GR127935 nor MDL100907 significantly modify the increase in the consolidation of learning induced by 8-OH-DPAT. Thus, the present findings suggest that stimulation of presynaptic 5-HT1B/1D receptors impairs the consolidation of learning whilst stimulation of 5-HT2A/2C receptors enhances it; the blockade of 5-HT2A receptors has no effects. In addition, 5-HT2 receptors seem to modulate this cognitive stage.
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PMID:Effects of the 5-HT receptor antagonists GR127935 (5-HT1B/1D) and MDL100907 (5-HT2A) in the consolidation of learning. 947 28