Single Cell action potential of rabbit sinoatrial node modulated by acetyl choline by Demir, Clark, Giles 1999 from CellML source

Description

NOTA BENE: The model parameter and variable units were revised
so that the model could be compiled with "unit conversion on;"

   (ABSTRACT) We have extended our compartmental model [Am. J.
Physiol. 266 (Cell Physiol. 35): C832–C852, 1994] of the
single rabbit sinoatrial node (SAN) cell so that it can simulate
cellular responses to bath applications of ACh and isoprenaline
as well as the effects of neuronally released ACh. The
model employs three different types of muscarinic receptors
to explain the variety of responses observed in mammalian
cardiac pacemaking cells subjected to vagal stimulation. The
response of greatest interest is the ACh-sensitive change in
cycle length that is not accompanied by a change in action
potential duration or repolarization or hyperpolarization of
the maximum diastolic potential. In this case, an AChsensitiveK
! current is not involved.Membrane hyperpolarization
occurs in response to much higher levels of vagal
stimulation, and this response is also mimicked by the model.
Here, an ACh-sensitive K+ current is involved. The wellknown
phase-resetting response of the SAN cell to single and
periodically applied vagal bursts of impulses is also simulated
in the presence and absence of the "beta-agonist isoprenaline.
Finally, the responses of the SAN cell to longer continuous
trains of periodic vagal stimulation are simulated, and this
can result in the complete cessation of pacemaking. Therefore,
thismodel is 1) applicable over the full range of intensity
and pattern of vagal input and 2) can offer biophysically
based explanations for many of the phenomena associated
with the autonomic control of cardiac pacemaking.

Equations

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