Inhibition by lead of the calcium plateau current at mouse motor nerve endings.

The inhibition by lead of motor terminal calcium plateau signals has been studied using extracellular, perineuronal electrodes applied to the M. triangularis sterni preparation of the mouse. The long-lasting calcium pateau signal induced by 3,4-DAP (250 mumol) and TEA (10 mmol) blockade of presynaptic potassium channels was irreversibly blocked by micromolar lead concentrations in a concentration-dependent manner. These results suggest that lead antagonizes neuronal calcium channels involved in transmitter release from motor nerve terminals.