Old cogs, new tricks: a scaffolding role for connexin43 and a junctional role for sodium channels?
Cardiac conduction is the process by which electrical excitation is communicated from cell to cell within the heart, triggering synchronous contraction of the myocardium. The role of conduction defects in precipitating life-threatening arrhythmias in various disease states has spurred scientific interest in the phenomenon. While the understanding of conduction has evolved greatly over the last century, the process has largely been thought to occur via movement of charge between cells via gap junctions. However, it has long been hypothesized that electrical coupling between cardiac myocytes could also occur ephaptically, without direct transfer of ions between cells. This review will focus on recent insights into cardiac myocyte intercalated disk ultrastructure and their implications for conduction research, particularly the ephaptic coupling hypothesis.
Center for Cardiovascular and Regenerative Biology, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA 24016, USA. Electronic address: saiv@vt.edu.
Rengasayee
R
Veeraraghavan
Center for Cardiovascular and Regenerative Biology, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA 24016, USA.
Steven
S
Poelzing
Center for Cardiovascular and Regenerative Biology, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA 24016, USA.
Robert G
RG
Gourdie
D000200:Action Potentials; D000818:Animals; D018031:Connexin 43 / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D006801:Humans; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009928:Organ Specificity; D061566:Voltage-Gated Sodium Channels / Q000378:metabolism*
D018031:Connexin 43; D061566:Voltage-Gated Sodium Channels
Conduction; Connexin; Ephaptic; Gap junction; Intercalated disk; Na(v)1.5; Perinexus; Sodium channel