Effects of some heavy metals on the action potentials of an identified Helix pomatia photosensitive neuron.

In the photosensitive MB neuron in the left parietal ganglion of Helix pomatia, the onset of light prolongs significantly (by about 40%) the duration of the action potential. The broadening of the action potential after the onset of light was found to be due to its calcium component and could not be induced after blocking Ca(2+) channels by Cd(2+) and Pb(2+) and in absence of Ca(2+) in medium. The blocking effect of both compounds was reversible. It was found that CdCl(2) exhibited a more intense blocking effect than PbCl(2).