Peripheral and central involvement of 5-hydroxytryptamine in control of interdigestive migrating contractions by motilin.

1. 为了研究5-羟色胺在胃动素外周作用中的作用，从供犬胃中分离胃后灌注人工血。结果，在离体胃中，胃动素引起的向幽门环迁移的收缩被灌注胃的5-羟色胺3受体拮抗剂完全抑制。由此可见，5-羟色胺参与了离体胃胃动素的作用。在同一系统中，还发现α -肾上腺素能受体和胆碱能神经元参与运动素的作用。研究了多种受体拮抗剂对em523诱导的胃肠道收缩的影响，在有意识的狗身上长期植入力传感器来测量胃肠道收缩。EM523，一种非肽胃动素激动剂，被发现以剂量相关的方式诱导胃iii期样收缩，并伴随血浆胃动素浓度的增加。经胆碱能、5-羟色胺3受体拮抗剂和多巴胺预处理后，可消除em523引起的胃收缩，但阿片受体拮抗剂和甲塞吉特对胃收缩无影响。这些在有意识的狗身上得到的结果与在孤立的胃里得到的结果一致本研究发现5-羟色胺神经元参与胃动素对胃肠道收缩的控制，但尚未阐明5-羟色胺神经元与胃动素受体之间的关系；这一点应该在将来加以澄清。还研究了5-羟色胺在中枢神经系统中对胃动素引起的消化间迁移收缩的控制作用，但尚未得到明确的结论；需要进一步的研究。

1. In order to study the role 5-hydroxytryptamine in the peripheral action of motilin, the canine stomach was perfused with artificial blood after the stomach was isolated from the donor dog. As a result, motilininduced contractions migrated toward the pyloric ring in the isolated stomach were completely inhibited by treatment of the perfused stomach with a 5-hydroxytryptamine 3 receptor antagonist. It is concluded that 5-hydroxytryptamine is involved in the action of motilin in the isolated stomach. In the same system, it was also found that alpha-adrenergic receptors and the cholinergic neuron were involved in the action of motilin.2. The effects of various receptor antagonists on EM523-induced contractions in the gastrointestinal tract were studied in conscious dogs in which force trasducers were chronically implanted to measure gastrointestinal contractions. EM523, a non-peptide motilin agonist, was found to induce phase III-like contractions in the stomach in a dose-related manner with concomitant increase in the plasma consentration of motilin. The EM523-induced contractions in the stomach were eliminated by pretreatment of dogs with cholinergic and 5-hydroxytryptamine 3 receptor antagonists, and dopamine, but the contractions were not influenced by opiate (mu) receptor antagonist and methysergide. These findings obtained in conscious dogs agree with those found in the isolated stomach.3 In the present study, it was revealed that 5-hydroxytryptamine neuron is involved in the control of contractions in the gastrointestinal tract by motilin, but the relationship between 5-hydroxytryptamine neuron and motilin receptors in the stomach has not been elucidated ; this should be clarified in the future. The role of 5-hydroxytryptamine in the CNS in the control of the interdigestive migrating contractions by motilin has been also studied, but no definite conclusion could be obtained ; further studies are needed.