DOUBLE EFFECT OF ETHANOL ON INTRACELLULAR CA2+ LEVELS IN UNDIFFERENTIATED PC12 CELLS

In PC12, a cellular line derived from a rat pheochromocytoma, ethanol (EtOH) induces a different effect depending on the concentration used. When resting cells are incubated with an alcohol concentration less t han or equal to 120 mM, the [Ca2+](i) increased with a double phase pa ttern. If the alcohol concentration was increased over 120-160 mM, EtO H reversed its effect and the [Ca2+](i) decreased. This decrease was s trongly inhibited if KCl-depoladzed cells were used and was completely abolished if the substrate constituted EtOH-chronically treated cells . The Ca2+ increase is the consequence of an activation of L-type volt age-activated channels, while the other voltage-dependent channels (N- type), the receptor-operated channels and the Ca2+ extrusion pump pres ent in these cells are not involved in EtOH action. These findings ind icate that EtOH can induce (by different mechanisms) both potentiating and inhibiting effects on [Ca2+](i) in pC12 cells in relation to the alcohol dose effectively present in the suspension medium.