The path-clamp method used within the whole-cell configuration in experiments with convoluted medullar oblongata sections obtained from white mongrel male rats aged 13 to 17 days evidenced that 5 mV of mexidol caused 96 +/- 2% inhibition of the excitation postsynaptic current in neurons of the medial vestibular nucleus generated by the depolarization step of 10 mV (holding potential = -70 my). This means that the antimotion sickness effect of mexidol has its origin in the ion mechanisms with involvement of the glutamate- and GABAergic components, primarily inhibition of ion currents through channels of the NMDA-receptor complex.