VOLTAGE-ACTIVATED POTASSIUM CURRENTS IN ACUTELY DISSOCIATED HIPPOCAMPAL DENTATE GYRUS NEURONS FROM NEONATAL RATS

We have studied outward currents of neurons acutely dissociated from t he dentate gyrus region of hippocampus using whole-cell and perforated patch recordings. Depolarizing voltage commands activated sustained o utward currents at all ages tested (P5-P30). Outward currents were blo cked by tetraethylammonium (10 mM) but not 4-aminopyridine (25 mM). Co mparison of sustained potassium current during postnatal development s howed a significant increase in current amplitude with age reaching a peak between P20 and P30. These results suggest an overall increase in the number of voltage-dependent ionic channels during development, sp ecifically those underlying TEA-sensitive potassium currents.