[Electrophysiological study of the effects of topiramate on neocortical neurons in rats]

The effect of topiramate (topamax) on the electrical activity of frontal cortical neurons of neoencephalon was studied by microelectrode techniques in rats. Topiramate upon acute intraperitoneal administration and microionophoretic application dose-dependently reduced the frequency of spike activity within 17 - 30 min after injection at a dose of 40 and 80 mg/kg. At the same time, the agent did not change the membrane rest potential, and the magnitude and form of action potentials. Microionophoretically applied topiramate decreased the excitatory response to electroosmotically applied ethanol at "small doses" (ejected current < 50 nA) and enhanced the neuronal depression induced by ethanol at "large doses" (ejected current > 50 nA). It is suggested that the attenuation of alcohol seeking behavior observed after topiramate administration is due to suppression of ethanol activating effects in neoencephalon neurons, while the alleviation of alcohol withdrawal is associated with the central depressant activity.