SPATIAL HETEROGENEITY OF INTRACELLULAR CA-2+ CONCENTRATION IN NONBEATING GUINEA-PIG VENTRICULAR MYOCYTES

被引:44
作者
WILLIFORD, DJ
SHARMA, VK
KORTH, M
SHEU, SS
机构
[1] UNIV ROCHESTER,MED CTR,DEPT PHARMACOL,601 ELMWOOD AVE,ROCHESTER,NY 14642
[2] UNIV ROCHESTER,SCH MED & DENT,DEPT PHARMACOL,ROCHESTER,NY 14642
[3] TECH UNIV MUNICH,INST PHARMACOL & TOXIKOL,W-8000 MUNICH 2,GERMANY
关键词
cardiac myocytes; fluorescent Ca[!sup]2+[!/sup] indicator; intracellular Ca[!sup]2+[!/sup] concentration; mitochondria;
D O I
10.1161/01.RES.66.1.241
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
The spatial distribution of intracellular Ca2+ concentration was determined by fluorescent digital imaging microscopy in fura-2-loaded quiescent cardiac myocytes isolated from guinea pig ventricle. Fluorescent ratio images revealed discrete as well as clustered bright fluorescent spots ('hot spots'), which occupied approximately 20-50% of an individual cell's area. The fluorescent intensity and the area of the hot spots were increased by agents that deplete Ca2+ in the sarcoplasmic reticulum, namely, ryanodine (20-40 nM) and caffeine (5-15 mM). However, when cells were exposed to agents that deplete mitochondrial Ca2+, such as the protonophore, carbonyl cyanide m-chlorophenyl-hydrazone (CCCP, 100-300 nM), or the inhibitor of electron transport, antimycin A (4-40 nM), the fluorescent intensity and the area of the hot spots were reduced. These results indicate that the spatial distribution of intracellular Ca2+ concentration in the ventricular myocytes of guinea pig is quite heterogeneous. The ability of CCCP and antimycin A, but not caffeine and ryanodine, to reduce the fluorescent intensity in the hot spots implies that Ca2+ compartmentation in the mitochondria is largely responsible for the intracellular Ca2+ heterogeneity seen in the present study.
引用
收藏
页码:241 / 248
页数:8
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