Abstract
The planar lipid bilayer and vesicle release experiments are two alternative
approaches used to study the function of the ryanodine receptor (RyR)
channel at the subcellular level. In this work, we combine models
of gating (Zahradn�kov� and Zahradn�k, Biophys. J. 71 (1996) 2996-3012)
and permeation (Tinker et al., J. Gen. Physiol. 100 (1992) 495-517)
of the cardiac RyR channel to simulate calcium release experiments
on sarcoplasmic reticulum vesicles. The resulting model and real
experimental data agreed well within the experimental scatter, confirming
indistinguishable properties of the RyRC in the vesicle preparation
and in the planar lipid bilayer. The previously observed differences
in calcium dependencies of the release and the gating processes can
be explained by binding of calcium within the RyRC conducting pore.
A novel method of analysis of calcium dependence of calcium release
was developed and tested. Three gating models of the RyRC, showing,
respectively, an increase, no change, and a decrease in calcium sensitivity
over time, were compared. The described method of analysis enabled
determination of temporal changes in calcium sensitivity, giving
potential for detection of the adaptation/inactivation phenomena
of the RyRC in both vesicle and in situ release experiments.
- 10320679
- calcium
- calcium,
- cations,
- channel
- channel,
- computer
- divalent,
- endoplasmic
- gating,
- gov't,
- ion
- kinetics,
- monovalent,
- myocardium,
- non-u.s.
- receptor
- release
- research
- reticulum,
- ryanodine
- simulation,
- support,
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