Voltage-gated sodium channels (NaV) are essential for the generation of action potentials and for cell excitability.NaV channels are activated in response to depolarization and selectively allow flow of Na+ ions. To date, nine NaV α subunits have been cloned and named NaV1.1-NaV1.9.The NaV channels are classified into two groups according to their sensitivity to Tetrodotoxin (TTX): TTX-sensitive (NaV1.1, NaV1.2, NaV1.3, NaV1.4, NaV1.6 and NaV1.7) and TTX-resistant (NaV1.5, NaV1.8 and NaV1.9). Mammalian sodium channels are heterotrimers, composed of a central, pore-forming α subunit and two auxiliary β subunits. Expression of the α subunit isoform is developmentally regulated and tissue specific. Sodium channels in the adult central nervous system and heart contain β1 through β4 subunits, whereas sodium channels in adult skeletal muscle have only the β1 subunit.n NaV1.6 is highly expressed in adult brain and localized at high density in nodes of Ranvier and axon initial segments and at lower density in dendrites and cell bodies of some neurons. NaV1.6 channels are also expressed at high levels in cerebellar Purkinje neurons