血管加压素对心理性应激大鼠胃排空的影响

目的:观察中枢性血管加压素(vasopressin,AVP)对应激所致大鼠胃排空变化的影响,探讨应激对胃排空的影响以及AVP在此过程中的作用.方法:大鼠置入盛有少量冷水的鼠笼中4℃放置4 h,制备大鼠急性心理性应激模型.造模前10 min,除对照大鼠外,其余大鼠随机分为4组,分别为假手术组、侧脑室注射AVP受体阻断剂组、静脉注射AVP受体阻断剂组和侧脑室注射生理盐水组.放射性免疫测定法分别测定大鼠血浆中促肾上腺皮质激素(ACTH)和皮质醇水平;酚红排泄法测定大鼠胃排空率.结果:大鼠4℃放置4 h后,血浆中的ACTH和皮质醇水平显著增高,同时胃排空率显著加快.中枢注射AVP受体拮抗剂后,血液中ACTH和皮质醇含量显著下降,伴随胃排空速度减慢.结论:寒冷刺激引起的下丘脑--腺垂体--肾上腺皮质轴的功能增强是胃排空速度增快的重要原因之一.AVP参与了上述过程.

Effect of vasopressin on the gastric emptying function in psychological stress rats

Objective:To investigate the effect of vasopressin(AVP) on the gastric emptying function in a rat model of psychological stress. Methods:Rats were received intracerebroventriculary injection(icv) with either normal saline or AVP V1 receptor antagonist,and some animal received intravenous injection(iv) of AVP V1 receptor antagonist. Ten min later,animals were subjected to a session of water avoidance stress for a period of 4 h,as previously described. Control animals were maintained in a similar cage without water avoidance for 4 h. The content of cortisone and ACTH in plasma were measured by radioimmunoassay(RIA). Gastric emptying was determined by the phenol red method. Results:Compared with control animals,the levels of ACTH and cortisone in plasma in water avoidance treated rats were increased. Water-avoidance stress stimulated gastric emptying,compared with those without exposure to stress. Intracerebroventricular injection of AVP V1 receptor antagonist could significantly reduce ACTH and cortisone content in plasma. Rate of gastric emptying were also reduced significantly. Conclusion:The enhancement of the hypothalamic-pituitary-adrenal axis function might be essential for the increased gastric emptying rate. These effects might be involved to the increased release of AVP.