MEMBRANE CURRENTS ELICITED BY THE EPILEPTOGENIC DRUG PENTYLENETETRAZOLE IN THE NATIVE OOCYTE OF XENOPUS-LAEVIS

The effects of the epileptogenic agent pentylenetetrazole (PTZ) on membrane currents of native oocytes of Xenopus laevis were studied. PTZ elicits a response that consists of two inward currents. The first one is interpreted to be due to a decrease of potassium permeability since: (1) the input resistance is increased; (2) the equilibrium potential is near that of potassium; (3) the current is decreased during administration of potassium channel blocking agents; and (4) the PTZ response can be mimicked by blocking potassium channels without PTZ application. The second one is interpreted to be due to an increase of chloride permeability since: (1) the input resistance is decreased; (2) the equilibrium potential is near that of chloride; and (3) the response is decreased during administration of chloride blocking agents. These findings correspond to some extent with those made in neurons.