| Abstract: | Neuronal response in a cortical slab isolated from the cat during surface application of strychnine was investigated in experiments on immobilized unanesthetized animals by means of intracellular recording techniques. Protracted depolarizing potentials (PDP) were found to occur spontaneously and in response to a single intracortical electrical stimulus in a proportion of the neurons. These potentials could be triggered by transformation of response along the lines of "paroxysmal depolarizing shift" (PDS) — hyperpolarization, with hyperpolarization replaced by depolarizing potentials. A further increase in depolarizing after-potentials resulted in the generation of PDP. These changes were normally accompanied by enhanced summated epileptiform activity in the isolated cortical slab. It is postulated that PDP were triggered by increased calcium conductance at the neuronal membrane during intensification of paroxysmal response in the isolated cortical slab.I. I. Mechnikov University, Odessa. Translated from Neirofiziologiya, Vol. 22, No. 1, pp. 19–23, January–February, 1990. |
