ABSTRACT
Adult male Sprague-Dawley rats given daily SC injections of 2.5 mg/kg or 10 mg/kg morphine sulfate (for eight days) decreased preference for a 5% (v/v) ethanol solution, and then increased ethanol preference during the postinjection period, relative to a saline control group. These bidirectional effects were directly related to morphine dosage. The results were interpreted as supporting the theory that alcohol drinking is reinforced through its interaction with the endogenous opioid system and can compensate for deficiencies in opioid receptor activity.
Subject(s)
Alcohol Drinking , Morphine/pharmacology , Animals , Injections, Subcutaneous , Male , Morphine/administration & dosage , Rats , Rats, Inbred Strains , Receptors, Opioid/drug effectsABSTRACT
Rats given a choice between a 5% alcohol solution and water will dramatically increase alcohol preference on the days following experience with inescapable electric footshocks, compared with unshocked animals. Although, total alcohol preference did not differ during shock days, an interaction occurred between shock stress and alcohol preference. Rats that initially preferred alcohol decreased alcohol preference during shock days, whereas, rats that initially avoided alcohol increased alcohol preference during shock days. Therefore, the stress of inescapable electric footshock has bidirectional effects on alcohol preference. These bidirectional effects depend on the temporal dynamics of alcohol consumption in relation to the shock experience and the initial alcohol preference.
