Fig. 3.
Inhibition of Nav1.4 sodium currents by SCI insecticides. A to C, representative traces of sodium currents through Nav1.4 channels recorded before and after 15 min of perfusion with 10 μM metaflumizone (A), RH-4841 (B), or DCJW (C). D, time course of sodium current inhibition caused by metaflumizone, RH-4841, and DCJW. Oocytes were held at a holding potential of −30 mV and stimulated once every minute with a test pulse (20 ms) to −10 mV that was preceded by a 2-s hyperpolarization to −120 mV. After 4 min of stable control recordings at −30 mV, insecticides were perfused into the bath for 15 min; peak sodium currents were normalized to the mean sodium current amplitude obtained during the 4 min of stable control currents before insecticide perfusion. Data were fitted using a first-order exponential decay function that yielded a single time constant (τ1); values are means ± S.E. of four or more individual experiments in separate oocytes.