Fig. 5.

Effect of intra-accumbal administration of the NMDA receptor antagonist AP-5 on drug seeking induced by intra-mPFC cocaine. The data summarized in A depict the response rate (Lever presses/Min) during the fifth component of the FI10(FR10) second-order schedule of reinforcement for the last self-administration (SA) and extinction (Ext) sessions as well as the reinstatement phase of the experiment. The response rates for all 10 components of the second-order schedule for the vehicle/cocaine and AP-5/cocaine treatments are shown in B. The error bars indicate ±SEM. The asterisk represents a significant difference from the vehicle control at that time point (p < 0.05; Tukey's HSD). Note that 3 μg AP-5 significantly increased the response rate relative to the vehicle control treatment during the third component. There were six to eight animals per treatment.