Résumé : By in situ hybridization with an oligonucleotide probe, we have studied the cellular distribution of the messenger RNA encoding the transcription factor zif268 (krox-24) in the adult intact rat striatum and regulation of its synthesis by acute treatment with the dopamine D1 receptor antagonist SCH-23390. Zif268 mRNA was found in the striatal medium-sized neurons and not in the large cells. Its levels were decreased by SCH-23390, suggesting activation of this immediate early gene in the striatum through dopamine D1 receptor stimulation.