Methods 12healthy adult Wistar rats were selected without limitation of sex and div ided by random drawing lots into experiment group(pethidine hydrochloride was in-jected,n=9)and control group(normal saline was injected,n=3).

• 方法选用健康成年Wistar大鼠12只,雌雄不限,按随机法选9只为实验组(注射盐酸哌替啶),3只为正常对照组(注射等量生理盐水)。