EN
Oxadiazine insecticide, indoxacarb is known to block voltagegated Na channels (Nav) in insects but the mechanism of block is not yet well understood. There are indications that indoxacarb shifts slow inactivation curve in the hyperpolarizing direction. The conclusion coming from our experiments performed on cockroach DUM neurons is similar because strong artificial hyperpolarization eliminated effects of indoxacarb. In second series of experiments, the discharges in whole cockroach nerve cord under mechanostimulation of cercus were recorded. Indoxacarb (10-6 M) significantly decreased the cord activity. Pretreatment of preparation with scorpion alpha toxin (blocking Nav inactivation) abolished effect of indoxacarb. Thus, our results confirm the effects of indoxacarb on Nav steady state inactivation.