下丘脑催产素对大鼠摄食和胃动力的影响及调控研究

Effects of Hypothalamic Oxytocin on the Feeding and Gastric Motility in Rats

目的:探讨下丘脑催产素(OXT)对大鼠摄食和胃动力的影响及调控机制。方法:采用荧光金逆行追踪结合免疫组化实验,观察大鼠视上核(SON)与弓状核(ARC)之间的神经通路;采用核团置管术观察ARC微量注射OXT对大鼠摄食的影响;采用单极电刺激观察电刺激SON对大鼠胃运动的影响及ARC微量注射OXT对大鼠胃运动和胃排空的影响。结果:荧光金逆行追踪结合免疫组化实验显示大鼠SON与ARC之间存在神经通路;ARC微量注射OXT大鼠0-2 h、0-3 h和0-4 h摄食量显著下降,OXT受体拮抗剂阿托西班可完全阻断OXT的抑制摄食作用,注射OXT和缩胆囊素(CCK)受体拮抗剂MK-329混合液后,OXT对大鼠摄食的抑制作用被部分阻断;电刺激SON,大鼠胃运动幅度和频率显著增强,预先向ARC内微量注射阿托西班后再电刺激SON,电刺激SON对胃运动的促进作用进一步增强;ARC微量注射OXT后,大鼠胃运动幅度和频率显著降低,阿托西班可完全阻断OXT对胃运动幅度和频率的抑制作用,MK-329可部分阻断OXT对胃运动幅度和频率的抑制作用;ARC微量注射OTX后,大鼠胃排空率显著降低,阿托西班可完全阻断OXT对胃排空的抑制作用,MK-329可部分阻断OXT对胃排空的抑制作用。结论:SON-ARC内具有OXT神经通路,且该通路由CCK介导。

Objective: To investigate the effects of hypothalamic oxytocin(OXT) on the feeding and gastric motility in rats and its regulatory mechanism. Methods: The neural pathway between the supraoptic nucleus(SON) and arcuate nucleus(ARC) was observed by fluorescent gold retrograde tracing combined with immunohistochemical experiments;The effects of ARC microinjection of OXT on feeding in rats was observed by brain nuclei catheterization;The effects of electrical stimulation of SON on gastric motility in rats was observed by unipolar electrical stimulation;The effects of ARC microinjection of OXT on gastric motility and gastric emptying in rats was observed. Results: Fluorescent gold retrograde tracing combined with immunohistochemical experiments showed that there was a neural pathway between SON and ARC in rats;After microinjection of OXT into ARC, the food intake of rats decreased significantly at0-2 h, 0-3 h and 0-4 h. Atosiban, an OXT receptor antagonist, completely blocked the inhibitory effect of OXT. After injection of mixture of OXT and MK-329, a cholecystokinin(CCK) receptor antagonist, the inhibitory effect of OXT on feeding in rats was partially blocked;Electrical stimulation of SON increased the amplitude and frequency of gastric motility in rats, and the effects of electrical stimulation of SON was further enhanced after microinjection of atosiban into ARC;After microinjection of OXT into ARC, the amplitude and frequency of gastric motility in rats decreased significantly. Atosiban completely blocked the inhibition of OXT on the amplitude and frequency of gastric motility. MK-329 partially blocked the inhibition of OXT on the amplitude and frequency of gastric motility;After microinjection of OTX into ARC, the gastric emptying rate of rats decreased significantly. Atosiban completely blocked the inhibition of OXT on gastric emptying, while MK-329 partially blocked the inhibition of OXT on gastric emptying. Conclusions: SON-ARC has a OXT neural pathway, which is mediated by the CCK.