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Effects of morphine and naloxone on the motility of the gall bladder muscle strip of the guinea pig

Zhang Wanqin, Feng Zhenyuan, Mei Mahua

Department of Physiology, Dalian Medical College. Dalian, Liaoning, China

Abstract

Experiments were performed in vitro with the gall bladder smooth muscle strip of the guinea pig. It was found that morphine exerted markedly stimulatory effect on the motility of the gall bladder strip. This stimulatory effect was significantly reversed by the specific antagonist of the opiate receptor-naloxone, indicating that the opiate receptors may be present in the gall bladder muscle. Acetylcholine also increases the motility of the gall bladder strip, and this stimulatory effect could be abolished by atropine. Atropine also blocked the effect of morphine on the gall bladder. Isoprenaline could decrease the motility of the strip while norepinephrine could increase it. The former was blocked by practolol, and the latter by phentolamine. Both effects were not influenced by naloxone. Practolol and phentolamine did not influence the effect of morphine on the motility of the gall bladder muscle strip. These results suggest that morphine and its receptor may be involved in the regulation of the motility of the gall bladder, but in this mechanism neither #alpha#-nor #beta#-adrenergic receptors play a role.

Key words: Gall bladder muscle strip;Morphine;Naloxone;Reverse

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Citing This Article：

Zhang Wanqin, Feng Zhenyuan, Mei Mahua. Effects of morphine and naloxone on the motility of the gall bladder muscle strip of the guinea pig. Acta Physiol Sin 1985; 37 (2): (in Chinese with English abstract).