Sarcomeric calcium sparks activated by fiber depolarization and by cytosolic Ca2+ in skeletal muscle

被引：26

作者：

Schneider, MF

Klein, MG

机构：

[1] Dept. of Biochem. and Molec. Biology, University of Maryland, School of Medicine, Baltimore, MD

[2] Dept. of Biochem. and Molec. Biology, University of Maryland, School of Medicine, Baltimore, MD 21201

来源：

CELL CALCIUM | 1996年 / 20卷 / 02期

关键词：

D O I：

10.1016/S0143-4160(96)90101-3

中图分类号：

Q2 [细胞生物学];

学科分类号：

071009 ; 090102 ;

摘要：

Discrete highly localized elevations of myoplasmic [Ca2+], calcium 'sparks', have been detected in skeletal muscle fibers. During relatively small depolarizations of a fiber, the calcium sparks are several times larger than the average increase in [Ca2+] and can thus be clearly resolved. The spark event frequency increases steeply with increasing depolarization, so that for larger depolarizations the discrete microscopic [Ca2+] elevations blend together and become indistinguishable in the average macroscopic [Ca2+] transient. Spontaneous calcium sparks also occur in the absence of voltage sensor activity, in which case they are activated by myoplasmic Ca2+. Both the voltage-activated and Ca2+-activated events originate at the location of the triad within the sarcomere. Calcium sparks appear to constitute the elementary unit of calcium release activation in skeletal muscle.

引用

页码：123 / 128

页数：6

共 27 条

[1] INTRAMEMBRANE CHARGE MOVEMENT RESTORED IN DYSGENIC SKELETAL-MUSCLE BY INJECTION OF DIHYDROPYRIDINE RECEPTOR CDNAS [J].