The Effects of Footshock on the Reinforcing Efficacy of Cocaine in Male Long-Evans Rats

• Main Author: Hendrick, Elizabeth S.
• Format: Others
• Published: VCU Scholars Compass 2005
• Subjects: relief; anxiety; stress; self-administration; Medical Pharmacology; Medical Sciences; Medicine and Health Sciences
• Online Access: http://scholarscompass.vcu.edu/etd/1540; http://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=2539&context=etd

Many links exist between cocaine abuse and stress. The literature and laboratory studies in rats suggest that this could be because stress increases the reinforcing efficacy of cocaine. Using male Long-Evans rats, experiments in this thesis tested effects of footshock on the reinforcing efficacy of cocaine using a progressive ratio schedule of reinforcement. They also examined effects of footshock on the reinforcing efficacy of a half-maximal dose of cocaine. Finally, they tested the effects of footshock on cocaine self-administration in rats initially resistant to acquisition of cocaine self-administration. Footshock did not increase reinforcing efficacy of cocaine on a PR schedule of reinforcement, nor did it enhance sensitivity to a half-maximal dose of cocaine. Footshock did, however, cause acquisition of cocaine self-administration in acquisition-resistant rats. Therefore, while footshock stress may be capable of sensitizing acquisition-resistant rats to the reinforcing efficacy of cocaine, it does not appear that it significantly increases the reinforcing efficacy of cocaine in rats with a history of cocaine self-administration.