Functional roles of the L-type calcium channel on cardiac pacemaking — Insights from bifurcation analysis

摘要

In this study, we used the bifurcation analysis technique to study the functional roles of the maximal channel conductace of the L-type calcium channel coded by isoforms of Cav1.2 and Cav1.3 in a novel mathematical model of murine sinoatrial node (SAN) cells. A continuous variation in the maximal channel conductance of ICaL (gCaL, 1.2 and gCaL, 1.3) was carried out to reveal the emergence and annihilation of pacemaking action potentials (APs), changes in AP's cycle length, maximal diastolic potential and overshoot. Parameter value range of the channel conductances essential for generating or annihilating pacemaking APs were identified. Our data demonstrates that the L-type calcium channel current contributes to cardiac pacemaking APs, especially during their diastolic and up-stroke depolarization phases.