Both sodium channel II and IIA alpha subunits are expressed in rat brain

Abstract

Complementary DNAs encoding four distinct isoforms of the large (α) subunit of the voltage sensitive sodium channel have been isolated from rat brain mRNA (1,2,3). Two of these, II and HA, differ in only 36 nucleotides within the coding region and in only 6 amino acids (1, 3). Because of the possible functional significance of electrophysiological differences between isoforms, it is important to establish definitively that the sequence differences are not due to cloning artifacts and to estimate the relative prevalence levels of the two mRNAs in rat brain.