Figure 1

The effect of a 14-day infusion of SCH23390 on inter-injection intervals (Panel A) and calculated cocaine levels (Panel B) in representative sessions from the same rat before, during and after implantation of the Alzet pumps. Open circles represent programed response-independent (non-contingent) injections. The red symbols represent the loading injections. The green symbols represent injections in the first half of the maintenance phase at the 0.3 µmol/kg, while the pink symbols represent injections in the second half of sessions at the 3.0 µmol/kg unit dose.