Effects of the epileptogenic agent bicuculline methiodide on membrane currents induced by N-methyl-D-aspartate and kainate (oocyte; Xenopus laevis).

The actions of bicuculline methiodide (BIC) on N-methyl-D-aspartate (NMDA)- and kainate (KA)-activated ion channels were studied using Xenopus oocytes, previously microinjected with RNA from rat brains. BIC reduced NMDA- and, with a lower efficiency, KA-induced membrane currents in a dose-dependent manner. The BIC effect on both agonist responses showed a voltage dependency with a lower grade of reduction at more positive holding potentials. By increasing the concentrations of the agonists, the reduction of the agonist-induced membrane currents by BIC was increased.