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Binding of Morphine in Tolerant Rats
Author(s) -
PENNAHERREROS A.,
TAMPIER L.,
SANCHEZ E.
Publication year - 1968
Publication title -
british journal of addiction to alcohol and other drugs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.424
H-Index - 193
eISSN - 1360-0443
pISSN - 0007-0890
DOI - 10.1111/j.1360-0443.1968.tb05275.x
Subject(s) - morphine , respiration , lethal dose , pharmacology , medicine , drug tolerance , anesthesia , biology , toxicology , anatomy
Summary The proportion of bound morphine: [100 (total‐free morphine): (total morphine)] in the liver and of free morphine in the blood of tolerant rats receiving a lethal dose of morphine by intravenous infusion at 1, 3, 8 and 16 days after withdrawal were studied. The results were compared with those obtained in two groups of non‐tolerant controls. One of them receiving a lethal dose of morphine and the other receiving under artificial respiration the lethal dose of tolerant rats. The alkaloids were estimated after chromatographic separation of free morphine from normorphine and other metabolites. The lethal dose of tolerant rats was significantly higher in the first 3 days after withdrawal than in the controls. The proportion of bound morphine found in the liver of tolerant rats in the first 3 days after withdrawal was significantly higher than in the controls. This increased ability of the liver of tolerant rats to bind morphine was not the consequence of the larger dose injected, since it was not observed in non‐tolerant controls receiving the same dose under artificial respiration. In spite of the fact that the lethal dose of morphine in the first 3 days after withdrawal was significantly higher in the tolerant rats as compared with the non‐tolerant controls, the blood levels of free morphine in both groups were not significantly different.