Impairment of acquisition of a DRL schedule following prolonged ethanol consumption

Two groups of male hooded rats (N = 9) were given either ethanol or sucrose solutions as their only source of fluid for six months. Thirty days after the ethanol treatment, the rats were reduced to 85% of their free-feeding weights and allowed to obtain 45 mg of food pellets on an FR 1 schedule fof five consecutive days. Subsequently, the rats were tested on four DRL schedules (6. 12, 18, 24 sec). There was no difference between the two groups on FR 1 or DRL 6 sec schedules; however, when the DRL interval was lengthened to 12, 18, and 24 sec, the ethanol group required more sessions than the sucrose group to reach criterion performance. After increases in the DRL interval, the modal interresponse time of the ethanol group shifted more slowly than that of the sucrose group.