Perinexi are privileged sites for cardiac action potential transmission via ephaptic coupling: a finite element modeling study

Abstract

Many life-threatening arrhythmias occur due to defects in cardiac conduction. While conduction relies principally on gap junctional coupling, in pathological situations when gap junctional coupling is reduced, action potential propagation may be supported through negative electrical potentials occurring in intercalated discs, a mechanism known as ephaptic coupling. Recent studies have shown that in intercalated discs, Na+ channels form clusters that are preferentially located in perinexi (nanodomains that surround gap junctions, with narrow intermembrane spacing).