[Effect of cadmium ions on the bursting electrical activity of an identified neuron in Helix pomatia].

The effect of cadmium ions was studied on electrical activity of RPal bursting neuron of Helix pomatia. It is shown that 1 mM of Cd2+ ions completely blocks the neuronal bursting activity. If the peptidic modulating factor is added to the Cd2+-containing solution, the bursting activity is not blocked but even increases. It is suggested that Cd2+ ions block the neuronal bursting activity by inhibiting the calcium current in presynaptic terminals of a nonidentified peptidergic interneuron which under normal conditions secretes the modulating factor on the RPal neuronal soma eliciting its bursting activity.