Authors: Alexis B Peterson Daniel P Hivick Wendy J Lynch
Publish Date: 2014/01/25
Volume: 231, Issue: 13, Pages: 2661-2670
Abstract
Male and female rats selfadministered cocaine 15 mg/kg/infusion under extended access conditions 24 h/day 4 discrete trials/h for 10 days Rats were then given voluntary access to either an unlocked or locked running wheel for 1 2 6 or 24 h/day during the 14day abstinence period Separate groups of rats were housed in polycarbonate cages during abstinence to control for physical activity that the wheel may provide Subsequent cocaineseeking was assessed under a withinsession extinction/cueinduced reinstatement procedure Estrous cycle was monitored in females to determine whether the effectiveness of wheel running varied by estrous cycle phaseAlthough females ran more than males males were more sensitive to the effects of running and showed a dosedependent decrease in cocaineseeking with longer access resulting in greater suppression The dose–effect relationship was less straightforward in females and access to both a locked and unlocked wheel decreased cocaineseeking with effects dependent on estrous cycle phase Notably extended 6 and 24 h/day but not limited 1 and 2 h/day access to a wheel surmounted the heightened vulnerability observed in females during estrus
Keywords: