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PubMed · 6890929

[Plasma corticosterone concentration in morphine-dependent rats].

T Suzuki·M Shimada·T Yoshii·I Akiba·S Yanaura
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Abstract

The effects of morphine on plasma corticosterone concentration in rats were studied using the drug-admixed food method. Morphine was mixed with the powder form of rat food in concentrations of 0.5 mg/g, 1 mg/g, and 2 mg/g of food. Plasma corticosterone concentration in rats treated with morphine-admixed food increased significantly, and the increment depended on the morphine concentration of drug-admixed food. The time course change of plasma corticosterone concentration in rats treated with morphine-admixed food (1 mg/g food) for 1 week was similar to that of non-treated rats without the concentration at 9:00. The plasma corticosterone concentration of morphine-treated rats at 9:00 was significantly increased in comparison with that of non-treated rats. Furthermore, the plasma corticosterone concentration after withdrawal in morphine-treated rats increased with time, and a significant increment in corticosterone was observed at 24 hr after the withdrawal. Naloxone, injected subcutaneously into morphine-dependent rats, significantly increased plasma corticosterone concentration. Increment of plasma corticosterone concentration in rats treated with morphine-admixed food for 3 or 4 weeks was significantly different from the non-treated group. The increment of plasma corticosterone concentration after the withdrawal was in a morphine treatment period-related manner. By these results, we suggest that tolerance to the increment action in plasma corticosterone concentration of morphine does not develop for at least 4 weeks using the drug-admixed food method, and the drug-admixed food method could induce morphine dependence without disturbance of the circadian rhythm in plasma corticosterone.

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AnimalsCorticosteroneHumansMaleMorphineMorphine DependenceNaloxoneRatsRats, Inbred StrainsTime FactorsEnglish AbstractJournal Article

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T Suzuki, M Shimada, T Yoshii, I Akiba, S Yanaura. 1982. [Plasma corticosterone concentration in morphine-dependent rats].. https://pubmed.ncbi.nlm.nih.gov/6890929/

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