Effects of oil intake in the conditioned place preference test in mice

We investigated the effects of corn oil intake in the conditioned place pre ference (CPP) test in mice. Voluntary intake of corn oil in the Light box i n the CPP test showed place preference, but its peroral administration 60 m in before conditioning did not show either place preference or aversion. Ac quisition of the place preference by corn oil intake was blocked by i.p, in jection of SCH 23390 (0.03 mg/kg) and haloperidol (0.1 mg/kg), but not by t hat of (+/-)-sulpiride (100 mg/kg), (-)-sulpiride (100 mg/kg), and L-741,62 6 (1 mg/kg) 15 min before conditioning. These results suggest that stimulat ion of corn oil in the oral cavity, but not its postingestive effects, have positive reinforcing effects and the stimulation of corn oil is at least p artly mediated via dopaminergic systems through the D-1 receptors. Moreover , the present results suggest that the CPP test is useful for the study of preferable stimulation and rewarding effects of food intake. (C) 2000 Elsev ier Science B.V. All rights reserved.