Proc Natl Acad Sci U S A. 2009 Aug 18;106(33):14085-90. doi: 10.1073/pnas.0904817106. Epub 2009 Aug 3.

Mutation I810N in the alpha3 isoform of Na+,K+-ATPase causes impairments in the sodium pump and hyperexcitability in the CNS.

Clapcote SJ, Duffy S, Xie G, Kirshenbaum G, Bechard AR, Rodacker Schack V, Petersen J, Sinai L, Saab BJ, Lerch JP, Minassian BA, Ackerley CA, Sled JG, Cortez MA, Henderson JT, Vilsen B, Roder JC.

Source

Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5. s.j.clapcote@leeds.ac.uk

Abstract

In a mouse mutagenesis screen, we isolated a mutant, Myshkin (Myk), with autosomal dominant complex partial and secondarily generalized seizures, a greatly reduced threshold for hippocampal seizures in vitro, posttetanic hyperexcitability of the CA3-CA1 hippocampal pathway, and neuronal degeneration in the hippocampus. Positional cloning and functional analysis revealed that Myk/+ mice carry a mutation (I810N) which renders the normally expressed Na(+),K(+)-ATPase alpha3 isoform inactive. Total Na(+),K(+)-ATPase activity was reduced by 42% in Myk/+ brain. The epilepsy in Myk/+ mice and in vitro hyperexcitability could be prevented by delivery of additional copies of wild-type Na(+),K(+)-ATPase alpha3 by transgenesis, which also rescued Na(+),K(+)-ATPase activity. Our findings reveal the functional significance of the Na(+),K(+)-ATPase alpha3 isoform in the control of epileptiform activity and seizure behavior.