ETHANOL DEMAND AND THE EFFECT OF ALTERNATIVE REINFORCEMENT ON ETHANOL CONSUMPTION

Previous studies have demonstrated that drug self-administration is highly susceptible to contextual influences such as access to non-drug alternative reinforcers. These studies largely focused on cocaine and heroin, however. The present study therefore focused on how ethanol and sucrose (1) compare as reinforcers in rats, and (2) how these reinforcers might interact with each other. In Exp. 1, demand for ethanol was far more elastic than that for sucrose. Consistent with this finding, rats greatly preferred sucrose over ethanol when given a mutually-exclusive choice. The essential value (EV) – a behavioral economic measure reflecting inelasticity of demand – of ethanol and sucrose predicted rats’ preference. Exposure to the intermittent access (IA) procedure in the homecage – a method intended to emulate binge-withdrawal cycles of ethanol consumption – did not impact ethanol EV or preference measured in the operant chamber. Exp. 2 investigated whether suppression of the acquisition of the ethanol lever-press operant observed in Exp. 1 was due to the availability of sucrose. The main finding of Exp. 2 was that the introduction of the sucrose reinforcer to rats that had previously only had experience lever-pressing for ethanol significantly reduced ethanol EV. Exp. 3 investigated whether provision of sucrose in the homecage might similarly reverse escalated homecage ethanol consumption induced by the IA procedure. Though rats did escalate ethanol consumption over five weeks of IA, sucrose provision significantly decreased ethanol consumption to pre-escalation levels. Collectively, these results suggest that alternative reinforcer provision may be useful in curtailing dysregulated ethanol use.