Fig. 3.

(A) Effects of a 2-hour pretreatment with nepicastat (10 mg/kg) on yohimbine-induced reinstatement (0.3 mg/kg) in squirrel monkeys (N = 2). Data (mean ± S.E.M.) are expressed as the percentage of responding maintained during cocaine self-administration sessions. Yohimbine had a modest effect on responding during reinstatement, whereas a nepicastat pretreatment in combination with yohimbine enhanced responding to approximately 50% of levels maintained by cocaine self-administration. *P < 0.005, compared with vehicle control. (B) Reinstatement effects of nepicastat (10 mg/kg) administered alone as a 30- or 120-minute pretreatment in squirrel monkeys (N = 2). Data (mean ± S.E.M.) are expressed as the percentage of responding maintained during cocaine self-administration sessions. Nepicastat significantly increased response rates when administered 30 minutes before the start of the session. *P < 0.01, compared with vehicle control at the same pretreatment time. Coc, cocaine; Nep, nepicastat; Veh, vehicle; Yoh, yohimbine.