Impairment of acquisition of cocaine self-administration in rats maintained on a high-fat diet.

Variations in dietary constituents such as carbohydrate are known to alter psychostimulant function in brain. Relatively few studies have examined the reinforcing effects of psychostimulants in subjects maintained on high-fat diets. The present experiment compared the rate of acquisition of an operant response for intravenous (i.v.) cocaine infusions (0.2 mg/kg) in rats fed either a chow-pellet diet or a 35.9% (by weight) high-fat diet for 45 days prior to cocaine self-administration testing. Rats maintained on a high-fat diet for 45 days exhibited diminished acquisition of cocaine self-administration, and this effect was not a function of dietary-induced obesity. The results suggest that prolonged exposure to a high-fat diet diminishes the efficacy of cocaine reinforcement.