下丘脑室旁核orexin-A对大鼠摄食和胃动力影响及调控机制

目的:探讨下丘脑室旁核orexin-A对大鼠摄食和胃动力影响及调控机制。方法:采用免疫组化观察下丘脑室旁核(paraventricular nucleus,PVN)orexin受体表达情况;PVN注射orexin-A观察大鼠摄食、胃运动、胃酸分泌和胃排空的改变。结果:免疫组化实验显示大鼠PVN中存在orexin受体免疫阳性细胞。PVN注射orexin-A后,大鼠前三小时摄食增加,6 h和24 h摄食无显著改变。PVN微量注射orexin-A后,大鼠胃运动幅度和频率增加、胃排空增快并且胃酸分泌增多。[D-Lys-3]-GHRP-6可部分阻断orexin-A对摄食、胃运动、胃排空和胃酸分泌的促进作用,SB334867可完全阻断orexin-A对胃运动、胃排空和胃酸分泌的促进作用。结论:下丘脑室旁核orexin-A可能通过生长激素促泌素GHSR受体信号通路调控大鼠摄食及胃功能。

Effects of Orexin-A on the Feeding and Gastric Motility of Rats in Paraventricular Nucleus and Its Regulatory Mechanism

ABSTRACT Objective: To study the effect of orexin-A on the feeding and gastric motility of rats in paraventricular nucleus and its regulatory mechanism. Methods: The expression of PVN orexin receptor was observed by immunohistochemistry. The changes of food intake, gastric motility, gastric acid secretion and gastric emptying were observed after PVN injection of orexin-A. Results: Immunohisto- chemistry showed orexin receptor-positive immunoreactive cells in the PVN of rats. After PVN injection of orexin-A, the feeding of rats increased in the first three hours, and there was no significant change in 6h and 24 h. After microinjection of orexin-A into PVN, the gas- tric motility amplitude and frequency, gastric emptying and gastric acid secretion of rats were increased. [D-Lys-3]-GHRP-6 partially blocked the promotion of food intake, gastric motility, gastric emptying and gastric acid secretion by orexin-A. SB334867 completely blocked the promotion of orexin-A on gastric motility, gastric emptying and gastric acid secretion. Conclusion: Orexin-A in the hypotha- lamic paraventricular nucleus could regulate the feeding and gastric function through GHSR receptor signaling pathway.