5-羟色胺和胃动素在狗小肠移行性复合运动调控中的作用

应用慢性植入小肠腔外应力传感器记录清醒狗小肠移行性复合运动（ＭＭＣ）。在颈外静脉和支配１０￣１５ｃｍ肠段的空肠动脉内分别放置－硅胶管以备灌流药物的取血样品用。本研究观察了静脉和动脉注射药物对小肠ＭＭＣ的影响及ＭＭＣ不同时相血浆５－羟色胺（５－ＨＴ）和胃动素的浓度变化。结果表明：（１）ＭＭＣ不同时相血浆５－ＨＴ和胃动素浓度呈周期性变化,５－ＨＴ峰值在胃动素峰值之前出现。血浆５－ＨＴ浓度在ＭＭＣⅡ相后

Regulatory role of 5-hydroxytryptamine and motilin in migrating motor complex of small bowel in dogs

Migrating motor complex (MMC) was recorded by chronically implanted strain gauge transducers on the serosa of small bowel in conscious dogs. Two silastic catheters for injecting drugs and taking blood samples were put respectively in a vena jugularis externa and in a jejunal artery which perfused a 10-15 cm intestinal segment. The present study was undertaken to observe the effect of drugs administered intravenously and intraarterially on MMC and alterations of plasma 5-hydroxytryptamine (5-HT) and motilin in different phases of MMC. The results showed: (1) Levels of plasma 5-HT and motilin showed cyclical fluctuations in different phases of MMC, and 5-HT reached peak before peak of motilin. Plasma 5-HT level reached a peak (41.2 +/- 1.3) ng/ml] in the later period of phase II, which increased significantly as compared with phase I (22.4 +/- 1.1) ng/ml] (P < 0.01), but plasma motilin level had a peak (580.0 +/- 30.2) pg/ml] in phase III of MMC, which was higher than that in phase I (140.0 +/- 21.0) pg/ml] (P < 0.01). (2) Intravenous motilin and intraarterial 5-HT and motilin could induce phase III contraction in the canine proximal small bowel and in the perfused segment respectively. Amplitude of contractions caused by motilin was higher than that by 5-HT in the perfused segment. (3) 5-HT receptor antagonist, motilin antiserum, 5,6-dihydroxytryptamine and tetrodotoxin perfused intra-arterially inhibited expression of MMC in the perfused segment and its caudal propagation. We conclude that plasma 5-HT and motilin may be dominant factors which initiate MMC of canine small bowel, and 5-HT peak appears before peak of motilin. 5-HT neurons and motilin neurons in enteric nervous system may play an important role in controlling MMC of canine small bowel.