Figure 6.

Nepicastat does not affect maintenance of cocaine self-administration. After reaching maintenance levels of operant cocaine self-administration (Maint), rats were pretreated with vehicle (Veh Pre) or nepicastat (50 mg/kg, i.p.; Nep Pre) 2 h before cocaine self-administration sessions. Shown are mean ± SEM active lever responses and number of reinforcers obtained over a 2-h session. Maintenance values reflect an average number of responses and reinforcers obtained over the last 3 days of maintenance. Occasional active lever pressing during the 20-s timeout periods result in more active lever presses than reinforcers received. (N=6 per group).