Effect of wheel-running during abstinence on subsequent nicotine-seeking in rats.
BACKGROUND
Exercise appears to be a promising non-pharmacological treatment for nicotine addiction that may be useful for the vulnerable adolescent population.


OBJECTIVE
The aim of this study is to determine if wheel-running, an animal model of aerobic exercise, during an abstinence period would decrease subsequent nicotine-seeking in rats that had extended access to nicotine self-administration during adolescence.


METHODS
Male adolescent rats (n = 55) were trained to self-administer saline or nicotine infusions (5 or 10 μg/kg) under a fixed ratio 1 schedule with a maximum of 20 infusions/day beginning on postnatal day 30. After 5 days, access was extended to 23 h/day with unlimited infusions for a total of 10 days. After the last self-administration session, rats were moved to polycarbonate cages for a 10-day abstinence period where they either had access to a locked or unlocked running wheel for 2 h/day. Nicotine-seeking was examined following the 10th day of abstinence under a within-session extinction/cue-induced reinstatement paradigm.


RESULTS
Intake was higher at the 10 μg/kg dose as compared to the 5 μg/kg dose; however, intake did not differ within doses prior to wheel assignment. Compared to saline controls, rats that self-administered nicotine at either dose showed a significant increase in drug-seeking during extinction, and consistent with our hypothesis, exercise during abstinence attenuated this effect. Nicotine led to modest but significant levels of cue-induced reinstatement; however, in this adolescent-onset model, levels were variable and not affected by exercise.


CONCLUSIONS
Exercise may effectively reduce relapse vulnerability for adolescent-onset nicotine addiction.
Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, 1670 Discovery Drive, Suite 110, Charlottesville, VA 22911, USA.
Victoria
V
Sanchez
Catherine F
CF
Moore
Darlene H
DH
Brunzell
Wendy J
WJ
Lynch
D000375:Aging / Q000187:drug effects / Q000523:psychology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects; D003463:Cues; D058999:Drug-Seeking Behavior / Q000187:drug effects; D005108:Extinction, Psychological / Q000187:drug effects; D008297:Male; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D010805:Physical Conditioning, Animal / Q000523:psychology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D012646:Self Administration; D013375:Substance Withdrawal Syndrome / Q000523:psychology*
D009538:Nicotine