Ghrelin对大鼠小肠转运及消化间期移行性复合肌电活动的作用及机制

目的 探讨ghrelin对大鼠小肠转运和消化间期移行性复合肌电活动(MMC)的影响及作用机制.方法 大鼠禁食24 h,观察静脉给予不同剂量ghrelin对小肠转运的影响,及静脉给予ghrelin受体拮抗剂(D-Lys3)GHRP-6对ghrelin作用的影响.采用多道生理记录仪在大鼠清醒、禁食状态下监测消化间期MMC,观察静脉给予ghrelin对胃肠MMC的影响.分别给予阿托品、酚妥拉明、普萘洛尔、L-精氨酸及(D-Lys3)GHRP-6,探讨ghrelin对MMC的作用机制.结果 静脉给予ghrelin剂量依赖性地促进小肠转运,此作用可被(D-Lys3)GHRP-6阻断.静脉给予ghrelin促进胃肠MMC.阿托,品、L-精氨酸和(D-Lys3)GHRP-6不同程度地抑制ghrelin的促动力效应;酚妥拉明和普萘洛尔对ghrelin的促动力作用无显著影响.结论 Ghrelin可促进胃肠运动,这可能是通过胆碱能通路起作用,与NO通路关系密切,ghrelin受体GHS-R参与其促动力作用.

Effect of ghrelin on small intestinal transit and interdigestive gastrointestinal migrating myoelectric complex in rats

OBJECTIVE: To investigate the effects of ghrelin on small intestinal transit and intergigestive gastrointestinal migrating myoelectric complex (MMC) in rats. METHODS: After a 24-hour fasting, the rats with or without pretreatment with receptor antagonist (D-Lys3)GHRP-6 were given intravenous injections of ghrelin at different doses to observe the changes in small intestinal transit. The MMCs of the fasting rats were recorded using a multilead physiological recording system, and their changes observed in response to intravenous ghrelin injections, or to ghrelin injection following pretreatment with atropine, phentolamine, propranolol, L-arginine or (D-Lys3)GHRP-6, respectively. RESULTS: Ghrelin enhanced the small intestinal transit dose-dependently, and this effect was inhibited by application of ghrelin receptor antagonist. Ghrelin also showed excitatory effect on the MMCs, which was inhibited by atropine, L-arginine or (D-Lys3)GHRP-6, but not by propranolol and phentolamine. CONCLUSION: Ghrelin can promote gastrointestinal motilities, and its excitatory effects rely on the cholinergic pathway in close relation to nitric oxide pathway. Ghrelin receptor is involved in its action in promoting the gastrointestinal motilities.