D-cycloserine decreases both D1 and D2 dopamine receptors number and their function in rat brain.

Twenty-four hours after the implantation of the transstriatal probe D-cycloserine (3 mg/kg IP), a partial agonist of the strychnine-insensitive NMDA-associated glycine recognition site failed to change DA and DOPAC extracellular output in rat striatal dialysates. In extensively washed synaptic plasma membranes prepared both from cortices or striata of rats treated with D-cycloserine [3H]-MK 801 specific binding was increased. In contrast, in striatal membranes the Bmax values of both [3H]-SCH 23390 and [3H]-spiroperidol bindings to D1 and D2 dopamine receptors were decreased. Parallel decreases both of grooming behavior induced by the D1 agonist SKF 38393 (10 mg/kg IP) and of the hyperactivity elicited by the D2 agonist LY 171555 (0.3 mg/kg IP) in rat were observed.