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THE POSSIBLE INVOLVEMENT OF ADRENOCEPTORS IN THE INTESTINAL EFFECT OF MORPHINE IN MICE
Author(s) -
Wong ChakLam
Publication year - 1984
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1984.tb00873.x
Subject(s) - morphine , yohimbine , prazosin , phentolamine , (+) naloxone , inhibitory postsynaptic potential , propranolol , antagonist , pharmacology , chemistry , medicine , endocrinology , receptor
SUMMARY 1. The inhibitory effect of morphine on intestine was observed by following the intestinal transit of a charcoal meal. This inhibitory effect of morphine was antagonized by naloxone. 2. In addition, the inhibitory effect of morphine was also suppressed by prior administration of yohimbine and phentolamine. However, prazosin, a selective α 1 ‐adrenoceptor antagonist, had no effect on the inhibitory effect of morphine on intestinal transit. 3. Furthermore, prior administration of propranolol did not alter this effect of morphine. 4. These adrenoceptor antagonists by themselves, at the doses used, had no effect on the rate of intestinal transit of a charcoal meal in mice. 5. These results suggest that α 2 ‐adrenoceptors may be involved in the intestinal effect of morphine while α 1 ‐ and β‐adrenoceptors do not appear to play any significant role in this aspect of morphine action.