Cortical (K+)e and the stimulation induced blockade of spreading depression in the rat cerebral cortex

Waves of spreading depression (SD) no not penetrate into an electrically stimulated (10 Hz, 0.05 msec, 20-30 V) cortical area of rats. The blockade develops slowly and is proportional to the (K+)e increase in the stimulated cortex. After cessation of stimulation, (K+)e returns to the resting level within 20-30 sec, but the SD blockade continues for 2-3 min. It is suggested that the stimulation induced activation of a metabolic pump disrupts the autoregenerative mechanism of SD propagation by enhancing K+ reabsorption into neurons.