Electrocorticographic effects of topically applied ouabain, epinephrine and bicuculline

The effects of topically applied ouabain, epinephrine and bicuculline on the electrocorticographic activity were studied in unanesthetized cats with high cervical transection. Ouabain in a concentration of 25 X 10(-6) induced single intermittent spikes or paroxysms lasting for about 4-10 min. A 5% solution of bicuculline also induced paroxyms which lasted for many hours and were suppressed by topical epinephrine. Ouabain paroxysms became more vigorous when applied after epinephrine and bicuculline. Topical epinephrine dimished the ouabain discharges and the click evoked cortical responses. It is suggested that the epileptogenic activity of ouabain and bicuculline and its antagonization by epinephrine can be accounted for by the antagonistic effects of these agents on the electrogenic ion pumps such as inhibition and stimulation of the (Na + K) ATPase activity, respectively.