Chronic ethanol exposure alters calcium movements and the number of dihydropyridine (DHP) binding sites in the animal brain and in cultured neural cell lines. The present study investigates the effect of ethanol treatment on dihydropyridine- and omega-conotoxin (CgTx)- labelled calcium channels in undifferentiated and differentiated NG 108-15 cells. Following differentiation, the binding of [3H] -PN 200-110 increased by 48% while [125I]-CgTx binding increased by six fold. In accordance with data in the literature, undifferentiated cells exposed to ethanol (3 days) showed a large increase (70%) in DHP binding sites. In contrast, CgTx binding sites were unmodified by the treatment. Using differentiated cells, ethanol exposure induced a significant decrease (53%) in CgTx binding sites without altering those labelled by PN 200-110 (isradipine). These findings indicate that the effect of ethanol exposure on calcium channels may be dependent on the type of channel considered and on the status of the cells treated.