[Mechanisms of development and blockade of epileptic activity in the brain]

Experiments on mollusk neurons showed the presence of 3 types of neurons with different activity character and different sensitivity to convulsants. The highest sensitivity to corazol and other convulsants was characteristic of spontaneuosly active "impulse" motoneurons with the threshold dose of corazol being 1 X 10(-4) M. Intergrative neurons without background spontaneous activity were the least sensitive, with the threshold dose of corazol being 1-5 X 10(-3) M. "Impulse" cells of the mollusk were compared with epileptic neurons of the brain. It was shown that "impulse" and epileptic activity was brought about by a peculiar change in the ionic permeability of the membrane, activation of the channels of a slow ascending current, a slow growth of potassium permeability and the resultant appearance of an area of negative resistance in the volt-ampere characteristics of ionic currents of the membrane. The convulsants were capable of inducing these changes in the electrophysiological characteristics of the neuronal membrane, while classical anticonvulsants eliminated them.