Fig. 8.

Effects of dopamine D₂ receptor antagonist pretreatment to cocaine. Abscissae, eticlopride dose in mg/kg (left, “V” indicates pretreatment vehicle; all as pretreatment to 10 mg/kg cocaine), cocaine dose in mg/kg (right, “Sal” indicates saline). Ordinates, percentage cocaine-appropriate responses (top); response rate in responses per second (bottom). Data are groups means ± S.E.M. Group sizes (Swiss-Webster mice): eticlopride dose-effect and 0.032 mg/kg, n = 9; eticlopride 0.1 mg/kg, n = 8. Exceptions to these group sizes are indicated when some mice failed to respond at a particular drug dose and were not tested on a higher dose, when applicable. **, p < 0.01; ***, p < 0.001 versus cocaine alone.