Acute bouts of wheel running decrease cocaine self-administration: Influence of exercise output

• Published in: Pharmacology, biochemistry and behavior Vol. 150-151; pp. 94 - 99
• Main Authors: Smith, Mark A., Fronk, Gaylen E., Zhang, Huailin, Magee, Charlotte P., Robinson, Andrea M.
• Format: Journal Article
• Language: English
• Published: United States 01.11.2016
• Subjects: Animals; Cocaine - administration & dosage; Female; Motor Activity; Physical Conditioning, Animal; Rats; Rats, Long-Evans; Reinforcement Schedule; Self Administration; Self-administration; Wheel; Cocaine; Exercise; Rat
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/j.pbb.2016.10.001

Exercise is associated with lower rates of drug use in human populations and decreases drug self-administration in laboratory animals. Most of the existing literature examining the link between exercise and drug use has focused on chronic, long-term exercise, and very few studies have examined the link between exercise output (i.e., amount of exercise) and drug self-administration. The purpose of this study was to examine the effects of acute bouts of exercise on cocaine self-administration, and to determine whether these effects were dependent on exercise output and the time interval between exercise and drug self-administration. Female rats were trained to run in automated running wheels, implanted with intravenous catheters, and allowed to self-administer cocaine on a fixed ratio (FR1) schedule of reinforcement. Immediately prior to each test session, subjects engaged in acute bouts of exercise in which they ran for 0, 30, or 60min at 12m/min. Acute bouts of exercise before test sessions decreased cocaine self-administration in an output-dependent manner, with the greatest reduction in cocaine intake observed in the 60-min exercise condition. Exercise did not reduce cocaine self-administration when wheel running and test sessions were separated by 12h, and exercise did not reduce responding maintained by food or responding during a saline substitution test. These data indicate that acute bouts of exercise decrease cocaine self-administration in a time- and output-dependent manner. These results also add to a growing body of literature suggesting that physical activity may be an effective component of drug abuse treatment programs.