In situ hybridization of NT mRNA after an acute injection of saline, cocaine, amphetamine, or haloperidol in D3+/+ and D3−;/− mice. Mice were injected i.p. with a single dose of saline (SAL), cocaine (COC, 30 mg/kg), amphetamine (AMPH, 10 mg/kg), or haloperidol (HALO, 1 mg/kg), and killed 3 h after. Film autoradiograms show NT mRNA expression in coronal brain sections at the rostral and caudal striatal level.