Effect of low energy X ray on Helix identifiable neuron electrical activity

The giant cells of snail brain (Helix pomatia and Helix aspersa) are studied before, during and after low energy X rays irradiation. Electrophysiological data are recorded from 2 intracellular glass micropipettes. During the irradiation, a membrane resistance decrease and a depolarization are recorded, in accordance to dose and dose-rate. Thresholds are respectively 2,000 R and 1 kR.mn-1. Depolarization is partially reversible. The electrical threshold decreases in connection with depolarization: indeed, previous repolarization abolishes this effect. Spontaneous action potentials are often recorded during irradiation especially with a high dose-rate. Action potential shape also changes. Initially, it becomes higher with an increase of its rising-rate (dV/dt). Later, action potential becomes broader and smaller. Results are explained according to ionic theory of membrane potential