Date of Award:

2005

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Psychology

Advisor/Chair:

Timothy A. Shahan

Abstract

Drug self-administration has proven to be an adequate model for assessing variables that contribute to the maintenance of drug taking. The present experiment was concerned with the persistence of drug self-administration, a defining characteristic of drug dependence and abuse. Findings from studies of the resistance to change of food-maintained responding may contribute to a better understanding of the persistence of drug abuse and dependence. Using an animal model of alcohol self-administration, this study evaluated the effects of rate of reinforcement on the persistence of ethanol self-administration in rats in the face of behavioral (i.e., extinction) and pharmacological (i.e., naltrexone) disruptors. Four experimentally naive Long Evans rats were trained to respond for a 10% (vol/vol) ethanol solution on a multiple variable-interval (VI) 15-s VI 45-s schedule of reinforcement. Baseline response rates were higher in the component that provided higher rates of ethanol delivery. Consistent with behavioral momentum theory, responding was more resistant to extinction in the component with higher rates of ethanol delivery. Conversely, disruption with naltrexone (1.0, 3.0, 10.0 mg/kg, s.c.), injected one hour before the session, resulted in no differential resistance to change of responding. The results are interpreted in terms of the effect of naltrexone on the incentive-motivational properties of the stimulus context.

Checksum

8fcfd593122db3e2bf5cf0b8c0eb832f

Included in

Psychology Commons

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