Abstract
Determination of the calcium spark amplitude distribution is of critical
importance for understanding the nature of elementary calcium release
events in striated muscle. In the present study we show, on general
theoretical grounds, that calcium sparks, as observed in confocal
line scan images, should have a nonmodal, monotonic decreasing amplitude
distribution, regardless of whether the underlying events are stereotyped.
To test this prediction we developed, implemented, and verified an
automated computer algorithm for objective detection and measurement
of calcium sparks in raw image data. When the sensitivity and reliability
of the algorithm were set appropriately, we observed highly left-skewed
or monotonic decreasing amplitude distributions in skeletal muscle
cells and cardiomyocytes, confirming the theoretical predictions.
The previously reported modal or Gaussian distributions of sparks
detected by eye must therefore be the result of subjective detection
bias against small amplitude events. In addition, we discuss possible
situations when a modal distribution might be observed.
- 9929467
- algorithms,
- aniline
- animals,
- biological,
- calciu,
- calcium
- carlo
- cells,
- channel
- channel,
- channels,
- compounds,
- computer
- computer-assisted,
- contraction,
- cultured,
- electrophysiology,
- energy
- fluorescence,
- gating,
- gov't,
- heart,
- image
- ion
- l-type,
- m,
- metabolism,
- method,
- microscopy,
- models,
- monte
- muscle
- muscle,
- myocardial
- myocardium,
- non-u.s.
- p.h.s.,
- patch-clamp
- pipiens,
- processing,
- proteins,
- rana
- rats,
- receptor
- release
- research
- reticulum,
- ryanodine
- sarcoplasmic
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