[Effect of x-rays on the pacemaker neurons of Helix pomatia].

The effect of superlethal doses of ionizing radiation on exciting and electrical properties of giant neurons of the central nervous system of Helix pomatia has been investigated. At early times following irradiation the excitability does not significantly change whereas the membrane potential, resistance and pump-induced hyperpolarization increase. At later times, a stabilization of these parameters is followed by a diminution of resistance, a decrease of membrane potential and pump-induced hyperpolarization, and even the neuron death.

[Relation between sodium pump activity and the osmotic pressure of the medium].

The dependence of electrogenic sodium pump activity on the tonicity of the surrounding medium was studied on snail giant neurons. It has been shown that the activity of electrogenic sodium pump in hypertonic media increases as compared to that in hypotonic media in neurons with low Na content, and decreases in neurons with high Na content. It has been found that the number of ouabain molecules bound with the membrane increases in hypotonic media as compared to its binding in iso- and hypertonic media.