Gating Currents Associated with Sodium and Calcium Currents in an Aplysia Neuron

Abstract

In a voltage-clamped aplysia neuron (R15), depolarization beyond -30 millivolts produces an inward sodium current. Depolarization beyond -10 millivolts produces an additional inward calcium current with slower kinetics than the sodium current. When these ionic currents have been suppressed and capacitive currents subtracted out, a small outward displacement current can be seen with depolarizations beyond -30 millivolts. An additional, slower displacement current is seen with depolarizations beyond -10 millivolts. The currents have an exponential decay with an increase in rate per 10 degrees C increase in temperature of about 3 and are thought to be sodium and calcium gating currents.