ACUTE EXPOSURE TO INORGANIC LEAD MODIFIES HIGH-THRESHOLD VOLTAGE-GATED CALCIUM CURRENTS IN RAT PC12 CELLS

Acute exposure to 1, 10 and 50 mu M lead acetate solutions irreversibl y decreased calcium currents in 21 of 30 nerve growth factor-different iate PC12 cells. In five cells, however, calcium currents irreversibly increased following lead exposure. Lead was equally effective at bloc king the peak and sustained components of the calcium current. These d ata suggest complex interactions between neurotoxicologically relevant lead concentrations and high-threshold calcium currents in mammalian cells. They provide further support for the notion that at least one t arget of lead's toxic action is the voltage-gated calcium channel.