Numerical Bifurcation Analysis of Pacemaker Dynamics in a Model of Smooth Muscle Cells

Abstract

Evidence from experimental studies shows that oscillations due to electro-mechanical coupling can be generated spontaneously in smooth muscle cells. Such cellular dynamics are known as \textit{pacemaker dynamics}. In this article we address pacemaker dynamics associated with the interaction of ${\text{Ca}}^{2+}$ and ${\text{K}}^{+}$ fluxes in the cell membrane of a smooth muscle cell. First we reduce a pacemaker model to a two-dimensional system equivalent to the reduced Morris-Lecar model and then perform a detailed numerical bifurcation analysis of the reduced model. Existing bifurcation analyses of the Morris-Lecar model concentrate on external applied current whereas we focus on parameters that model the response of the cell to changes in transmural pressure. We reveal a transition between Type I and Type II excitabilities with no external current required. We also compute a two-parameter bifurcation diagram and show how the transition is explained by the bifurcation structure.

29 pages, 34 figures

Cited by in corpus (1)

• Influence of Sodium Inward Current on Dynamical Behaviour of Modified Morris-Lecar Model