| Resurgence is defined as the recurrence of a previously but no longer reinforced behavior when a more recently reinforced behavior undergoes extinction. The present study investigated the effects of chlordiazepoxide (CDP), a member of the class of drugs known as benzodiazepines, on the resurgence of lever pressing responses emitted by male Sprague-Dawley rats. The general procedure was as follows: An operant (left lever presses) was reinforced and subsequently extinguished. Then, a second operant (right lever presses) was reinforced. Finally, 0, 1, 3, 10, and 30 mg/kg doses of CDP were administered via intraperitoneal injections to groups of nine animals each during 3 consecutive days of 1-hr exposure to concurrent extinction schedules. Slightly more left lever pressing (the resurgence response) occurred in the 1 mg/kg group than in the control group, while dose-dependent decreases in resurgence, as well as overall responding, occurred in the 3, 10, and 30 mg/kg groups relative to control levels. These results are discussed in terms of their similarity to those found in investigations of the effects of benzodiazepines on extinction. |
