Do age-associated changes of voltage-gated sodium channel isoforms expressed in the mammalian heart predispose the elderly to atrial fibrillation?

Table 1 Properties of voltage-gated sodium channel isoforms

Voltage-gated sodium channel isoform	Tissue	Gene	Amino acid length	Activated	Inactivated	Associated β-subunit
Nav1.1	Brain	SCN1A	2009aa (human and rat)	-33 mV	-72 mV	β1, β2, β3, β4
Nav1.2	Brain	SCN2A	2005aa (human); 2006aa (rat)	-24 mV	-53 mV	β1, β2, β3, β4
Nav1.3	Brain	SCN3A	1951aa (human and rat)	-23 to -26 mV	-65 to -69 mV	β1 and β3
Nav1.4	Skeletal muscle	SCN4A	1836aa (human); 1840aa (rat)	-26 to -30 mV	-56 mV	β1
Nav1.5	Heart	SCN5A	2016aa (human); 1951aa (rat)	-47 mV	-84 mV	β1, β2, β3, β4
Nav1.6	Brain	SCN8A	1980aa (human); 1976aa (rat)	-37.7 mV	-98 mV	β1 and β2
Nav1.7	PNS	SCN9A	1977aa (human); 1984aa (rat)	-31 mV	-61 to -78 mV	β1 and β2
Nav1.8	PNS	SCN10A	1957aa (human)	-16 to -21 mV	-30 mV	Not established
Nav1.9	PNS	SCN11A	1792aa (human); 1765aa (rat)	-47 to -54 mV	-44 to -54 mV	Not established

Illustrating the standardised nomenclature, regional tissue where the isoform predominantly located, gene, amino acid length, activation and inactivation membrane potentials and associated beta subunits. PNS: Peripheral nervous system; aa: Amino acids; mV: millivolts. Adapted from Catterall et al[23], 2005, with permission.