THE EFFECTS OF D-AMPHETAMINE ON THE REINFORCING EFFECTS OF FOOD AND FLUID USING A NOVEL PROCEDURE COMBINING SELF-ADMINISTRATION AND LOCATION PREFERENCE

Using a laboratory animal procedure designed to measure two aspects of behavior related to commodity seeking (self-administration and locati on preference), five individually housed adult rhesus monkeys lived in three chambers: fluid-(sweetened Kool-Aid(R) solution) related cues a nd oral fluid self-administration were specific to one end chamber, fo od pellet-related cues and food self-administration were specific to t he other end chamber, and no food cues or fluid cues were available in the middle chamber. Throughout the 10 h experimental day, monkeys exp erienced multiple food, fluid, choice (food versus fluid), and no-comm odity sessions. Oral d-amphetamine (AMPH; 0.5-1.5 mg/kg) or placebo wa s administered before the sessions to determine if this anorectic drug would differentially alter food and fluid self-administration. The ef fects of AMPH on the length of time monkeys spent in each chamber, whe n the stimulus lights indicating commodity availability were not illum inated (location preference) were also determined. AMPH decreased both food and fluid self-administration, but responding for fluid was redu ced to a greater extent than responding for food. AMPH, however, incre ased the length of time monkeys spent in the food chamber, even when n o stimulus lights indicating food availability were illuminated. The i ncrease in the length of time spent in the food chamber was predicted by the decrease in the number of fluid deliveries, not the number of f ood deliveries. These results indicate that the relationship between s elf-administration and location preference, as measures of reinforcing effects, is not completely concordant. The current procedure may prov e useful in comparing these two measures of reinforcing effects with o ther reinforcers.