The effects of d-amphetamine on intake of food and a sweet fluid containing cocaine

Using a laboratory animal procedure designed to measure two aspects of rein forcement (self-administration and location preference), five adult rhesus monkeys each lived in three chambers: oral cocaine self-administration (0.2 6 mg/kg/delivery cocaine hydrochloride in a sweet fluid) was specific to on e end chamber, food self-administration was specific to the other end chamb er, and no food cues or fluid cues were available in the middle chamber. Th roughout the 10-h experimental day monkeys experienced multiple food, cocai ne, and choice (food vs. sweet cocaine fluid), sessions. Oral d-amphetamine (AMPH; 0.5-1.5 mg/kg) or placebo was administered before the sessions to d etermine if this anorectic drug would differentially alter food and sweet c ocaine fluid self-administration. Further, the effects of AMPH on the lengt h of time a monkey spent in each chamber, when the stimulus cues indicating commodity availability were not present (Location preference) were determi ned. AMPH produced dose-dependent decreases in both food and cocaine self-a dministration without affecting choice behavior. AMPH also increased the le ngth of time monkeys spent in the food chamber, even when no stimuli indica ting food availability were present. These results indicate that the relati onship between self-administration and location preference measures of rein forcement is not completely concordant. The current procedure may prove use ful in studying these two measures of reinforcement. (C) 1999 Elsevier Scie nce Inc.