Distinct subpopulations of DRG neurons based on Na⁺ current (<i>I_Na</i>) inactivation kinetics.

Abstract

<p><b><i>A</i></b>, Representative traces ensemble for Rapidly/Slowly-inactivating <i>I_Na</i> acquired using whole-cell patch-clamp. Holding potential: −80 mV; test potentials are indicated for each trace. Superimposed Rapidly/Slowly-inactivating <i>I_Na</i> were evoked by a series of voltages steps to potentials ranging between −70 and +40 mV from a holding potential of −80 mV (bottom). For illustrative purposes, current traces from −50 to +30 mV are shown. <b><i>B</i></b>, Curve fitting examples and time constants (<i>tau</i>) for the decay phases from Rapidly/Slowly-inactivating <i>I_Na</i> traces. Single exponential functions are represented by gray lines. Holding potential: −80 mV; test potentials are indicated for each trace. <b><i>C</i></b>, Dot plots represent current decay/inactivation time constant fitted to a single exponential process at the indicated potential. <b><i>D</i></b>, Cumulative probability distribution of inactivation <i>ταυ</i> values obtained at the indicated conditioning potentials.</p