The effects of heavy charged particles--alpha-particles and deuterons accelerated by cyclotron to the energies of 30.3 and 15.4 MeV accordingly--on nerve's excitability (amplitude of an action potential (AP) and speed of AP propogation has been studied. The local irradiation of a little segments of nerve by particles having high LET has been used. The differences in dose curves of AP parameters were detected both during the influence of particles, and during the influence of particles on a nerve treated with isopropyl alcohol. The results showed the AP amplitude reducing that was more expressed in case of alpha-particles, and the AP speed decreasing that was more expressed in case of deuterons. During irradiation, the AP blocked by isopropyl alcohol was rehabilitated, and then was disappeared irreversible. The injury of nerve during irradiation had local character and did not influence on neighbor non-irradiated regions.