بررسی میزان خمیازه ناشی از بروموکریپتین در موش های صحرایی کلستاتیک

The purpose of this study was investigation of effect of cholestasis on bromocriptine-induced yawning in male rats. Bromocriptine, the agonist of dopamine receptors (especially "D2"), causes yawning in male intact rats. In the present study, cholestasis was produced in male rats by surgery and ligation of common bile duct. The number of yawning induced by intraperitoneal injection of bromocriptine (11 mg/kg) was compared in cholestatic rats with sham operated and control groups. Immediately after injection of the drug and putting animals on the frame of behavioral study, the number of yawning was determined in a period of one hour. Obtained results, indicated significant difference in the number of bromocriptine-induced yawning between cholestatic rats and the other two groups. There wasn't significant difference between sham and control rats. These results indicate that some changes occur in cholestatic rats which increase sensitivity and response of dopamine receptors. Since it is proved that dopamine agonist-induced yawning is mediated via nitric oxide, and also level of nitric oxide is increased in cholestasis, it can be supposed that the mentioned response may be due to elevated level of nitric oxide. On the other hand, increased number of yawning in cholestatic rats may be due to increased level of endogenous opioids in these animals.