Invertebrate voltage-gated sodium channel (Nav) (Nav)

The invertebrate voltage-gated sodium channel (Nav) is a large transmembrane protein that plays a fundamental role in the initiation and propagation of action potentials within the nervous systems of insects and other invertebrates [Dong, 2007]. It functions by opening a selective pore in response to membrane depolarization, allowing an influx of sodium ions that further depolarizes the cell membrane [Dong et al., 2014]. This channel is the primary molecular target for several major classes of insecticides, including pyrethroids, DDT, and oxadiazines, which are critical for agricultural pest control and the management of disease vectors [Soderlund, 2012]. Pyrethroids and DDT exert their effect by binding to the channel and slowing its inactivation, leading to prolonged sodium currents, repetitive nerve firing, and eventual paralysis [Zlotkin, 1999]. In contrast, newer agents like indoxacarb act as state-dependent blockers that inhibit sodium current, resulting in a different pathway to paralysis [Silver et al., 2014]. From a public health perspective, these channels are vital targets for controlling mosquitoes that transmit malaria, dengue, and Zika virus [Hemingway et al., 2004]. However, the widespread use of these chemicals has led to the emergence of knockdown resistance (kdr) mutations, which significantly reduce the sensitivity of the channel to insecticides and pose a major challenge to global health initiatives [Dong et al., 2014].

Other names

Insect voltage-gated sodium channelPara-type sodium channelVoltage-dependent sodium channelNav1-type sodium channel

Pyrethroids and DDT act as sodium channel modulators that delay the closing (inactivation) of the channel, leading to prolonged sodium currents and repetitive firing [Soderlund, 2012; Zlotkin, 1999]. In contrast, oxadiazines and semicarbazones act as state-dependent sodium channel blockers that inhibit the flow of sodium ions, leading to paralysis [Silver et al., 2014].