Unaltered [3H]GBR-12935 binding after chronic treatment with dopamine active drugs.

Rats were injected intraperitoneally with haloperidol 0.5 mg/kg, raclopride 1 mg/kg, bromocriptine 2.5 mg/kg, d-amphetamine 2.5 mg/kg, or cocaine 10 mg/kg twice daily for 21 days. The animals were sacrificed 72 h after last injection. Control rats were injected with saline, following the same schedule. The radioligand [3H]GBR-12935 was used as a presynaptic marker for dopamine neurites. There were no significant differences in [3H]GBR-12935 binding to striatum between drug-treated rats and controls.