AJP - Gastrointestinal and Liver Physiology, Vol 246, Issue 4 386-G392, Copyright © 1984 by American Physiological Society

ARTICLES

Role of enkephalins in regulation of basal intestinal water and ion absorption in the rat

R. Fogel and R. B. Kaplan

Intraluminal administration of naloxone (10(-4) M), a mu-opiate receptor antagonist, or diprenorphine (10(-6) M), an opiate receptor antagonist with high affinity for both delta- and mu-receptors, decreased basal in vivo water and electrolyte absorption in the jejunum and ileum but not the colon of the rat. Diprenorphine (10(-5) M) decreased basal colonic water transport. These changes were not due to a reduction in mucosal Na-K-ATPase activity. Intravenous atropine prevented as well as abolished the changes in water transport due to naloxone. The diprenorphine-induced changes were not altered by atropine. Naloxone and diprenorphine acted by different receptors. Pretreatment with naloxone (10(-4) M) prevented the increase in water transport due to morphine, a mu-agonist, whereas a higher concentration of naloxone (10(-3) M) was required to inhibit the increase due to D-Ala-methionine-enkephalinamide, a delta-receptor agonist. In contrast, diprenorphine (10(-6) M) abolished the absorption caused by morphine and D-Ala-methionine-enkephalinamide. Diprenorphine (3 X 10(-7) M) partially prevented the morphine-induced increase in water absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				A. R. Dehpour, H. Rastegar, M. Jorjani, F. Roushanzamir, K. Joharchi, and A. Ahmadiani Subsensitivity to Opioids Is Receptor-Specific in Isolated Guinea Pig Ileum and Mouse Vas Deferens after Obstructive Cholestasis J. Pharmacol. Exp. Ther., June 1, 2000; 293(3): 946 - 951. [Abstract] [Full Text]