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Responding for Oral Ethanol after Naloxone Treatment by Alcohol‐Preferring AA Rats
Author(s) -
Hyytiä P.,
Sinclair J. D.
Publication year - 1993
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.1993.tb00810.x
Subject(s) - (+) naloxone , ethanol , alcohol , antagonist , opioid antagonist , narcotic antagonist , anesthesia , free access , morphine , medicine , endocrinology , chemistry , zoology , psychology , receptor , biochemistry , biology , world wide web , computer science
The present study examined the effect of a relatively nonselective opioid antagonist, naloxone, on lever pressing for oral ethanol by the alcohol‐preferring AA rats. The AAs, housed continually in operant chambers with free access to food and water, learned to respond for 10% oral ethanol during daily 60‐min alcohol access periods indicated by a stimulus light. The rats developed stable ethanol responding, resulting in mean ethanol intakes of 1.2 g/kg/60 min and measurable blood alcohol levels. In the first experiment, single systemic injections of naloxone (0.05–2.5 mg/kg) had no effect on the initial rate of responding; dose‐dependent decreases were observed later during the alcohol access. The second experiment examined the effects of repeated injections of 0.5 and 2.5 mg/kg naloxone on 5 consecutive days. Naloxone suppressed responding dose‐relatedly over the treatment days. In contrast to the effects of single injections, repeated injections with 2.5 mg/kg naloxone produced progressive decreases within the first minutes of access. The results suggest that naloxone may attenuate the reinforcing actions of ethanol.