Sucrose, ethanol, and sucrose/ethanol reinforced responding under variable-interval schedules of reinforcement.
Adding sweeteners to ethanol solutions is a common method of inducing rats to consume ethanol. However, it has usually been assumed that it is the sweet taste and/or the calories contained in the sweet solution that controls consumption. The present experiment examined the role of ethanol in controlling responding reinforced by ethanol or an ethanol/sucrose mixture compared with sucrose solutions of various concentrations. After initiation to self-administer 10% (v/v) ethanol using the sucrose-substitution method, rats were trained to respond under a concurrent VI 5" VI 5" schedule. During one condition, responding on one lever was reinforced by the presentation of 10% ethanol, and responding on a second lever was reinforced by water or one of the following sucrose solutions: 1% (w/v), 1.5%, 2%, 2.5%, 3%, and 5%. During a subsequent condition, responding reinforced by a 10% ethanol/2% sucrose mixture was compared under the concurrent schedule with responding reinforced by water, 2%, 2.5%, 3%, 5%, or 10% sucrose (w/v). The results indicated that the ethanol or ethanol/sucrose mixture maintained more responding than did sucrose solutions that were sweeter. Data support the conclusion that, after initiation, the taste and/or pharmacological effects of ethanol had become an important component of the reinforcing stimulus independent of the sweetener.
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Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157-1083, USA.
Samson
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Brice
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D000428:Alcohol Drinking / Q000523:psychology*; D000818:Animals; D001245:Association Learning / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage; D005518:Food Preferences / Q000523:psychology; D008297:Male; D009042:Motivation; D051381:Rats; D017208:Rats, Wistar; D012055:Reinforcement Schedule; D013395:Sucrose / Q000008:administration & dosage*; D013649:Taste / Q000187:drug effects
D000431:Ethanol; D013395:Sucrose