DOPAMINE D1 AND D2 ANTAGONISTS BLOCK L-DOPA-INDUCED AIR-STEPPING IN DECEREBRATE NEONATAL RATS

L-DOPA administered to neonatal rats suspended in air elicits stereoty pic locomotor activation termed air-stepping: it can be dose-dependent ly blocked by a dopamine (DA) D1 or D2 antagonist. In order to determi ne whether the forebrain is the site for this blockade. decerebrate 5- day-old rats wen pretreated subcutaneously with either the DA D1 recep tor antagonist SCH 23390 (16 mg/kg), the DA D2 receptor antagonist spi perone (6 mg/kg), or vehicle before receiving 100 mg/kg L-DOPA. Both a ntagonists blocked L-DOPA-induced air-stepping in both decerebrate and intact pups.