Journal article
Polymorphism of Ca2+ Sparks Evoked from In-Focus Ca2+ Release Units in Cardiac Myocytes
Biophysical journal, Vol.86(1), pp.182-190
01/2004
DOI: 10.1016/S0006-3495(04)74095-3
PMCID: PMC1303781
PMID: 14695261
Abstract
Ca
2+
sparks are the elementary release events in many types of cells. Here we present a morphometric analysis of Ca
2+
sparks (i.e., amplitude and kinetic parameters) using an approach that minimizes the confounding factor of the detection of out-of-focus events. By activation and visualization of Ca
2+
sparks from Ca
2+
release units under loose-seal patch-clamp conditions, we found that the amplitude and rising rate of in-focus sparks exhibited a broad modal distribution, whereas spark rise time and spatial width appeared to be stereotyped. Spark morphometrics were constant irrespective of the latency of spark production and the time-dependent L-type Ca
2+
channel activation. Polymorphism of Ca
2+
sparks in terms of variable amplitude and rising rate was evident for events from the same release units, and intra- and interrelease unit variability contributed equally to the overall variability. The rising rate, a reporter of the underlying Ca
2+
release flux, displayed a strong positive correlation with spark amplitude, but a negative correlation with spark rise time, an index of Ca
2+
release duration. On the basis of Ca
2+
spark morphometrics measured here, we suggested a model in which cohorts of variable number of ryanodine receptors are activated in the genesis of Ca
2+
sparks, and the ensuing negative feedback overrides the regenerative Ca
2+
-induced Ca
2+
release to extinguish the ongoing Ca
2+
spark.
Details
- Title: Subtitle
- Polymorphism of Ca2+ Sparks Evoked from In-Focus Ca2+ Release Units in Cardiac Myocytes
- Creators
- Jian-Xin Shen - Department of Physiology, Medical School of Xi'an Jiaotong University, Xi'an 710061, ChinaShiQiang Wang - Department of Physiology, Medical School of Xi'an Jiaotong University, Xi'an 710061, ChinaLong-Sheng Song - Department of Physiology, Medical School of Xi'an Jiaotong University, Xi'an 710061, ChinaTaizhen Han - Department of Physiology, Medical School of Xi'an Jiaotong University, Xi'an 710061, ChinaHeping Cheng - Department of Physiology, Medical School of Xi'an Jiaotong University, Xi'an 710061, China
- Resource Type
- Journal article
- Publication Details
- Biophysical journal, Vol.86(1), pp.182-190
- Publisher
- Biophysical Society
- DOI
- 10.1016/S0006-3495(04)74095-3
- PMID
- 14695261
- PMCID
- PMC1303781
- ISSN
- 0006-3495
- eISSN
- 1542-0086
- Grant note
- DOI: 10.13039/501100001809, name: National Natural Science Foundation of China; DOI: 10.13039/501100012336, name: Major State Basic Research Development Program of China; DOI: 10.13039/100000002, name: National Institutes of Health; DOI: 10.13039/100000049, name: National Institute on Aging
- Language
- English
- Date published
- 01/2004
- Academic Unit
- Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Biochemistry and Molecular Biology; Internal Medicine
- Record Identifier
- 9984094481302771
Metrics
8 Record Views