Expression and Function of Inositol 1,4,5-Trisphosphate Receptors in the Heart

Martha Iveth Garcia, Darren Boehning
2015 Biophysical Journal  
during EADs; and 5) the transition from phase-2 to phase-3 EADs. We show that: 1) increasing RyR leakiness and/or SR Ca uptake rate promotes DADs, but can either suppress or potentiate EADs; 2) EADs can occur after a long plateau phase, and random opening of L-type Ca channels in plateau voltage prevents Ca waves and thus Ca oscillations in the long plateau phase in which both cytosolic and SR Ca remain high; 3) two distinct DAD mechanisms exist_a non-Ca wave mediated spontaneous SR Ca release
more » ... nd Ca wavemediated spontaneous SR Ca release; and 4) Ca accumulation under Ca overload conditions can cause a transition from phase-2 EADs to phase-3 EADs. These simulations not only recapitulated most of the known complex EAD and DAD dynamics but also allowed the underlying ionic and dynamical mechanisms to be analyzed, providing novel insights into these arrhythmogenic AP dynamics.
doi:10.1016/j.bpj.2014.11.1449 fatcat:sxsj3qjzcnbc7hc2agpkahhjiu