Figure 8.

Basal and amphetamine-stimulated dopamine efflux in the nucleus accumbens (nAcc) of D1–M4-KO and control mice. A, Basal dopamine efflux. Basal dopamine levels were determined via in vivo microdialysis. Data are expressed as means ± SEM (n = 6 or 7) of microdialysis samples 1–3 (see Materials and Methods for details). B, Amphetamine-stimulated dopamine efflux. D1–M4-KO mice and control littermates were injected with amphetamine (2 mg/kg, s.c.) at the 90 min time point (arrow). Data are expressed as means ± SEM (n = 6 or 7). *p < 0.05 versus control; ^#p < 0.05 versus basal dopamine efflux.