Channel name | NaV1.6 |
Description | Voltage-gated sodium channel α subunit |
Other names | NaCh6,1 PN4,2 CerIII3 |
Molecular information | Human: 1980aa, O95788, Q9NYX2, A9UQD0, AF050736, AF225988, chr. 12q13,4 SCN8A |
| Rat: 1976aa, L39018, AF049239, AF0492401,2 |
| Mouse: 1976aa, Q60858, AF050736, AF225988,5,6 chr. 15[64],5 |
|
Scn8A
|
Associated subunits | β1, β2 |
Functional assays | Voltage-clamp, neurotoxin-activated ion flux, voltage-sensitive dyes |
Current | INa |
Conductance | Not established |
Ion selectivity | Na+ |
Activation | Va = –8.8 mV (mouse α subunit in Xenopus oocytes with cut-open oocyte voltage-clamp)6 |
| Va = –17 mV (mouse α subunit with β1 and β2 in Xenopus oocytes with cut-open oocyte voltage-clamp)6 |
| Va = –26 mV, τa = 0.51 ms and 4.65 ms at –10 mV (mouse α subunit with inactivation removed and β1 and β2 in Xenopus oocytes with cut-open oocyte voltage-clamp)7 |
| Va = –37.7 mV, τa not determined (rat α subunit in Xenopus oocytes with macropatch voltage-clamp)2,7 |
Inactivation | Vh = –55 mV, τh = 1.2 and 2.1 ms at –10 mV, τh = 0.98 and 11.6 ms at 10 mV (mouse α subunit in Xenopus oocytes with 500-ms depolarizations using two-electrode voltage-clamp)6 |
| Vh = –51 mV, τh = 7.1 ms at –20 mV, τh = 0.78 and 8.1 ms at 10 mV (mouse α subunit with β1 and β2 in Xenopus oocytes with 500-ms depolarizations using two-electrode voltage-clamp)6 |
| Vh = –97.6 mV, τh = 1 ms at –30 mV (rat α subunit in Xenopus oocytes with 5-s depolarizations using macropatch voltage-clamp)2 |
Activators | Veratridine, batrachotoxin (based on studies with rat brain sodium channels) |
Gating modifiers | α-Scorpion toxins and sea anemone toxins, which all slow inactivation8 |
Blockers | Nonselective: tetrodotoxin (EC50 = 1 nM in rat,2 6 nM in mouse6), saxitoxin; local anesthetic, antiepileptic, and antiarrhythmic drugs |
Radioligands | [125I]α-scorpion toxin, [3H]batrachotoxin, [3H]saxitoxin |
| [3H]tetrodotoxin (based on studies with rat brain sodium channels) |
Channel distribution | Somatodendritic distribution in output neurons of the cerebellum, cerebral cortex, and hippocampus; Purkinje cells in the cerebellar granule cell layer; brainstem and spinal cord, astrocytes, and Schwann cells; DRG; nodes of Ranvier of sensory and motor axons in the PNS; nodes of Ranvier in the CNS1,9,10,11 |
Physiological functions | Action potential initiation and transmission in central neurons and their myelinated axons; partially responsible for the resurgent and persistent current in cerebellar Purkinje cells12 |
Mutations and pathophysiology | Point mutation in II S4-S5 causes cerebellar ataxia in jolting mice13; gene disruption causes motor endplate disease in mice5 |
Pharmacological significance | Potential target for antiepileptic and analgesic drugs |