Ethanol and magnesium suppress nickel-induced bursting activity in leech Retzius nerve cells

In the present study we have examined effects of ethanol and magnesium on Ni(2+)-induced bursting of leech Retzius cells. Saline with 3 mmol/l NiCl2 induced spontaneous bursting activity, characterized by rapid depolarizations to a plateau level during which bursts of action potentials occurred. To test for the mechanism of bursting initiation external Na+ was completely removed. Removal of external Na(+) in presence of 3 mmol/l NiCl2 terminated the bursting activity. Application of 2% ethanol solution significantly decreased the bursting frequency, duration and amplitude of depolarization plateaus, and the number of spikes per plateau. Solution containing 10 mmol/l Mg2+ almost completely abolished the oscillatory activity of the neurons and completely suppressed action potential generation. We conclude that ethanol and magnesium suppress Ni(2+)-induced epileptic activity.