A, B, NMDA receptor antagonists inhibit dopamine-induced IEG expression in rat primary striatal cultures. Northern blots from rat primary striatal culture probed with c-fos. A, Cultures were treated for 30 min with dopamine (50 μm). Pretreatment for 4 hr with MK-801 (1 μm) blockedc-fos induction; n = 4. B, Cultures were treated for 30 min with either dopamine (50 μm), SKF 38393 (50 μm), or SKF 82958 (50 μm). Pretreatment for 30 min with MK-801 (50 μm) or APV (100 μm) prevented c-fos induction;n = 8.