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.