Impulsive choice as a predictor of acquisition of IV cocaine self- administration and reinstatement of cocaine-seeking behavior in male and female rats.
Drug abuse and impulsive choice are related in humans. In female rats, impulsive choice predicted the rate of acquisition of IV cocaine self-administration. The objectives of the present experiments were to: (a) compare impulsive choice in males and females, (b) extend previous research on impulsive choice and acquisition of cocaine self-administration to males, and (c) compare males and females during maintenance, extinction, and reinstatement of cocaine-seeking behavior. Male and female rats were trained on an adjusting delay task in which a response on one of two levers yielded one food pellet immediately, and a response on the other resulted in three pellets after an adjusting delay that decreased after responses on the immediate lever and increased after responses on the delay lever. A mean adjusted delay (MAD) was used as the quantitative measure of impulsivity. In Experiment 1, MADs were analyzed for sex differences. In Experiment 2, acquisition of cocaine self-administration was examined in rats selected for high (HiI; MADs < or =9 seconds) or low (LoI; MADs > or =13 seconds) impulsivity. In Experiment 3, HiI and LoI groups were compared on maintenance and extinction of cocaine self-administration and cocaine-primed reinstatement of drug-seeking behavior. There were no sex differences in impulsive choice; however, HiI male and female rats acquired cocaine self-administration faster than their LoI counterparts. LoI females responded more on a cocaine-associated lever during maintenance and extinction than HiI females, but HiI females showed greater reinstatement of cocaine-seeking behavior than all other groups at the highest dose tested (15 mg/kg). Thus, individual differences in impulsive choice were associated with differences in cocaine-seeking behavior. Impulsive choice and sex may be additive vulnerability factors in certain phases of drug abuse.
Perry
Jennifer L
JL
Division of Pharmacology and Toxicology, Minneapolis Medical Research Foundation, Minneapolis, MN 55404, USA. perry050@umn.edu
Nelson
Sarah E
SE
Carroll
Marilyn E
ME
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002755:Choice Behavior; D003042:Cocaine / Q000008:administration & dosage*; D019970:Cocaine-Related Disorders / Q000523:psychology*; D003216:Conditioning, Operant; D004195:Disease Models, Animal; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D005260:Female; D007175:Impulsive Behavior / Q000523:psychology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects; D012054:Reinforcement, Psychology; D012646:Self Administration / Q000523:psychology; D012727:Sex Characteristics
D018765:Dopamine Uptake Inhibitors; D003042:Cocaine