Effects of pre-session treatments with the N-substituted BZT analogs (JHW 007, AHN 1-055 and AHN 2-005) and the typical dopamine-uptake inhibitor methylphenidate on responding maintained in rats by a range of doses of cocaine or number of food pellets delivered. Saline (5 min), methylphenidate (5 min), JHW 007 (120 min), AHN 1-055 (30 min), and AHN 2-005 (30 min) were administered intraperitoneally at the designated times before sessions. Each point represents the mean ± SEM (N=6). Panels A-C. Effects on cocaine self-administration. Ordinates: Responses/sec. Abscissae: unit dose of cocaine injection (in mg/kg/inj) or EXT (extinction-no injection). Panel A. JHW 007 treatment: 0 mg/kg (filled circles, saline injections), 1.0 mg/kg (open circles), 3.2 mg/kg (open triangles up), and 10 mg/kg (open triangles down). Panel B. AHN 1-055 and AHN 2-005 treatments: Saline (filled circles), 10 mg/kg of AHN 1-055 (open diamonds), 10 mg/kg of AHN 2-005 (open squares). Panel C. Methylphenidate treatment: 0 mg/kg (filled circles, saline injections), 1.0 mg/kg (open circles), 3.2 mg/kg (open triangles up), and 10 mg/kg (open triangles down). Panels D and E. Effects on food presentation. Ordinates: Responses/sec. Abscissae: number of pellets delivered. Panel D. N-substituted BZT analogs: Saline (filled circles), 10 mg/kg of JHW 007 (open circles), 10 mg/kg of AHN 1-055 (open diamonds), 10 mg/kg of AHN 2-005 (open squares). Panel E. Methylphenidate: 0 mg/kg (filled circles, saline injections), 1.0 mg/kg (open circles), 3.2 mg/kg (open triangles up), and 10 mg/kg (open triangles down).