Abstract
Calcium sparks are local regenerative releases of Ca$^2+$ from
a cluster of ryanodine receptors on the sarcoplasmic reticulum. During
excitation-contraction coupling in cardiac cells, Ca$^2+$ sparks
are triggered by Ca$^2+$ entering the cell via the T-tubules
(Ca$^2+$-induced Ca$^2+$ release). However under conditions
of calcium overload, Ca$^2+$ sparks can be triggered spontaneously.
The exact process by which Ca$^2+$ sparks terminate is still
an open question, although both deterministic and stochastic processes
are likely to be important. In this article, asymptotic methods are
used to analyze a single Ca$^2+$ spark model, which includes
both deterministic and stochastic biophysical mechanisms. The analysis
calculates both spark frequencies and spark duration distributions,
and shows under what circumstances stochastic transitions are important.
Additionally, a model of the coupling of the release channels via
the FK-binding protein is analyzed.
- 14990462
- action
- animals,
- atpase,
- biological,
- calcium
- calcium,
- cardiac,
- cardiovascular,
- cell
- cells,
- channel
- channel,
- channels,
- comparative
- computer
- computing,
- conduction,
- contraction,
- cultured,
- electrophysiology,
- enzyme
- gating,
- gov't,
- heart
- heart,
- humans,
- inhibitors,
- ion
- l-type,
- magnetics,
- mathematical
- membrane
- membrane,
- models,
- muscle
- myocardial
- myocytes,
- neural
- neurological,
- neurons,
- non-u.s.
- p.h.s.,
- potentials,
- processes,
- rate,
- rats,
- receptor
- release
- research
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