Inhibitory action of morphine and chlorpromazine on defecation in mice
Li, B.H.; Yang, X.Y.
Zhongguo Yao Li Xue Bao 7(1): 31-33
1986
ISSN/ISBN: 0253-9756 PMID: 2945380 Document Number: 277952
A plastic tube (10 .times. 1.8 mm) was evacuated immediately after having been put into the rectum of mice. Inhibition of the tube-evacuation from the rectum was used as a criterion of the effects of drugs on defecation. Morphine hydrochloride (Mor, 2.5-5 mg/kg, sc) and chlorpromazine hydrochloride (CPZ, 2-4 mg/kg, sc) produced an inhibition of the defecation reflex in mice. Intracerebroventricular injection of Mor 2.5-5 .mu.g and CPZ 2-4 .mu.g also inhibited such a reflex. Inhibition of the defecation reflex caused by Mor 5 mg/kg sc was antagonized by naloxone (1 mg/kg, sc or 2 .mu.g, icv) and by amphetamine 5 mg/kg sc. However, the inhibition caused by CPZ 2 mg/kg sc was only antagonized by amphetamine 10 mg/kg sc and not affected by naloxone 1-4 mg/kg sc.