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EFFECTS OF MORPHINE ON CANINE INTESTINAL ABSORPTION AND BLOOD FLOW
Author(s) -
MAILMAN DAVID
Publication year - 1980
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1980.tb10852.x
Subject(s) - morphine , chemistry , blood flow , fissipedia , saline , carnivora , absorption (acoustics) , blood pressure , medicine , (+) naloxone , anesthesia , endocrinology , opioid , biochemistry , physics , receptor , acoustics
1 Intestinal absorption and blood flow were determined in anaesthetized fed or fasted dogs following rapid intravenous injections of morphine (0.01, 0.1, 1 mg/kg). 2 3 H 2 O and 22 Na were used to determine the unidirectional fluxes of Na + and H 2 O from saline perfused through the ileal lumen and the clearances of 3 H 2 O were used to determine total and absorptive site blood flow. 3 Net Na + and H 2 O absorption were increased at each dose of morphine in fed but not in fasted dogs, due primarily to increased absorptive fluxes. 4 Arterial pressure was decreased by morphine but mesenteric vein pressure was little affected. Absorptive site blood flow was increased by morphine due to decreased blood flow resistance but total blood flow resistance was little affected by morphine. 5 The absorptive fluxes of Na + and H 2 O were correlated with absorptive site blood flow in both fed and fasted animals. The secretory fluxes of Na + and H 2 O were correlated with estimated capillary pressure in fasted dogs but morphine decreased the secretory fluxes at a given capillary pressure in dogs which had been fed. 6 Naloxone (0.12 mg, i.v.) reversed the effects of morphine. The effects of morphine on the gut were reversed more slowly than on systemic blood pressure. 7 It was concluded that morphine can increase net absorption in fed dogs by a selective increase in intestinal absorptive site blood flow and thus increase absorptive fluxes by a washout effect but that there is also an epithelial effect, sensitized by feeding, which reduces the secretory fluxes of Na + and H 2 O.