Voltage gated sodium channels as drug discovery targets

Voltage-gated sodium (Na(V)) channels are a family of transmembrane ion channel proteins. They function by forming a gated, water-filled pore to help establish and control cell membrane potential via control of the flow of ions between the intracellular and the extracellular environments. Blockade of Na(V)s has been successfully accomplished in the clinic to enable control of pathological firing patterns that occur in a diverse range of conditions such as chronic pain, epilepsy, and cardiac arrhythmias. First generation sodium channel modulator drugs, despite low inherent subtype selectivity, preferentially act on over-excited cells which reduces undesirable side effects in the clinic. However, the limited therapeutic indices observed with the first generation demanded a new generation of sodium channel inhibitors. The structure, function and the state of the art in sodium channel modulator drug discovery are discussed in this chapter.