Fig. 6.

Interaction between a low dose of a dopamine D2 receptor antagonist, raclopride, and different doses of alcohol on ICSS performance in C57BL/6J and DBA/2J mice. Changes in BSR threshold (A and B) and MAX (C and D) after gavage with water (vertical bars) or alcohol (symbols) following i.p. injection with saline (Sal; open symbols) or the 0.03 mg/kg dose of raclopride (Rac; filled symbols) are shown for C57 (circles) and DBA mice (triangles). The D2 antagonist raclopride blocked and reversed the reward-potentiating effect of low-dose (0.6 mg/kg) alcohol in C57 mice (A), but did not affect alcohol potentiation of BSR in DBA mice (B). Values are expressed as the mean percentages of preinjection baselines (± S.E.M.) in the first 15 minutes after alcohol or water. In panels in which no significant interaction effects of raclopride and alcohol are seen, P values for significant main effects of alcohol are inset as text. *Significance versus water (H₂O) (<0.05); ^†significance versus saline pretreatment (<0.05).