Eberle-Wang K, Braun B T, Simansky K J
Department of Pharmacology, Medical College of Pennsylvania, Eastern Pennsylvania Psychiatric Institute, Philadelphia 19129.
Am J Physiol. 1994 Jan;266(1 Pt 2):R284-91. doi: 10.1152/ajpregu.1994.266.1.R284.
Serotonin (5-HT) produced concentration-dependent contractions of the isolated rat pylorus in vitro. Serotonergic contractions were antagonized by the calcium L-channel blocker, diltiazem, but not by tetrodotoxin or atropine. Three drugs that block 5-HT2 receptors, ketanserin, xylamidine, and methysergide, unsurmountably inhibited contractions to 5-HT. In contrast, antagonists of 5-HT3, 5-HT1A/1B, beta-adrenergic, or alpha 1-adrenergic receptors did not alter the response to 5-HT. Devazepide, an antagonist of cholecystokinin (CCK) type-A receptors, blocked contraction produced by CCK-8 but not by 5-HT. Conversely, the 5-HT2 antagonists did not affect CCK-stimulated contraction. These results suggest that 5-HT contracts the pylorus by a 5-HT2-like receptor on muscle and that this response occurs independently of CCKergic receptor mechanisms. Furthermore, the parallel between the overall pharmacological profile for serotonergic contraction of the pylorus and that observed previously for the anorectic action of peripheral 5-HT makes the pylorus a logical candidate for peripheral serotonergic control of feeding.
血清素（5-羟色胺，5-HT）在体外对分离的大鼠幽门产生浓度依赖性收缩作用。血清素能收缩作用可被L型钙通道阻滞剂地尔硫卓拮抗，但不能被河豚毒素或阿托品拮抗。三种阻断5-HT2受体的药物，酮色林、二甲苯脒和麦角新碱，不可克服地抑制了对5-HT的收缩反应。相比之下，5-HT3、5-HT1A/1B、β-肾上腺素能或α1-肾上腺素能受体的拮抗剂并未改变对5-HT的反应。胆囊收缩素（CCK）A 型受体拮抗剂德伐西匹能阻断CCK-8产生的收缩，但不能阻断5-HT产生的收缩。相反，5-HT2拮抗剂不影响CCK刺激的收缩。这些结果表明，5-HT通过肌肉上类似5-HT2的受体使幽门收缩，且这种反应独立于CCK能受体机制发生。此外，幽门血清素能收缩的整体药理学特征与先前观察到的外周5-HT厌食作用之间的相似性，使得幽门成为外周血清素能控制进食的合理候选者。
