Effects of Morphine and Metoclopramide on the Contractile Response of the Isolated Rat Small Intestine

Keimyung Medical Journal 1988;7(1):76-85.

백서적출소장편 운동변화에 대한 Morphine과 Metoclopramide의 영향

김수경

Abstract

Many reports have shown that morphine produces profound effects on the gastrointestinal motility that include changes in peristaltic activity; intramural pressure and sphincter tone. And recently; the effects of opiates on the gastrointestinal tract are complex and apparently involve both a peripheral and a central action; and have variety of animal species. Also; the author has been reported that the stimulatory effect of metoclopramide on gastrointestinal tract is related to augment acetylcholine release partially. Therefore; the author investigated the peripheral cholinergic property of morphine as comparative with cholinergic action of metoclopramide in the isolated rat (normal and morphine-tolerant: 20mg/kg i. p. for 7days) small intestine. The results obtained are summarized as follows: 1. Morphine (10~8 ? 10~5M) decreased dose-dependently the motility of the normal isolated rat small intestine; but increased the tone of it. Metoclopramide (10"8-10"5M) increased the motility and tone of the isolated rat small intestine. 2. In the morphine-tolerant rat; morphine-induced contractile response of small intestine was less sensitive to morphine than that of the normal rat; and morphine(lCT8 ? 10~7M) produced inhibitory effect on the motility and tone of isolated rat small intestine. 3. Morphine-induced contractile response was inhibited by naloxone markedly; and mstoclopra-mide-induced contractile response was inhibited by atropine pretreatment markedly. 4. Morphine produced partially inhibitory effect on the metoclopramide-indueed contractile response in the morphine-tolerant rat. 5. Morphine or metoclopramide-induced contractile response was not affected markedly by dibenamine(10"8M); propranolol(10~8M) and hexamethonium(10~8M) in the normal isolated rat small intestine.