Pacemaker activity of the rabbit sinoatrial node. A comparison of mathematical models.
In the past decade, three mathematical models describing the pacemaker activity of the rabbit sinoatrial node have been developed: the Bristow-Clark model, the Irisawa-Noma model, and the Noble-Noble model. In a comparative study it is demonstrated that these models, as well as subsequent modifications, all have several drawbacks. A more accurate model, describing the pacemaker activity of a single pacemaker cell isolated from the rabbit sinoatrial node, was constructed. Model equations, including equations for the T-type calcium current, are based on experimental data from voltage clamp experiments on single cells that were published during the last few years. In contrast to the other models, only a small amount of background current contributes to the overall electrical charge flow. The action potential parameters of the model cell, its responses to voltage clamp steps and its current-voltage relationships have been computed. The model is used to discuss the relative contribution of membrane current components to the slow diastolic depolarization phase of the action potential.
Wilders
R
R
Department of Physiology, University of Amsterdam, The Netherlands.
Jongsma
H J
HJ
van Ginneken
A C
AC
D000200:Action Potentials; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D004553:Electric Conductivity; D004594:Electrophysiology; D015640:Ion Channel Gating; D007473:Ion Channels / Q000378:metabolism; D008955:Models, Cardiovascular; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology / Q000502:physiology*
D007473:Ion Channels