Coexpression with auxiliary β subunits modulates the action of tefluthrin on rat Nav1.6 and Nav1.3 sodium channels

► Tefluthrin caused only resting modification of channels expressed without β subunits. ► The β1 and β2 subunits did not affect resting modification of Nav1.6 channels. ► Coexpression of Nav1.3 with the β1 and β2 subunits reduced resting modification. ► β-Subunits were required for use-dependent modification of Nav1.6 and Nav1.3 channels.