EFFECT OF LOW-TEMPERATURE ON THE CYTOSOLIC FREE CA2+ IN RAT VENTRICULAR MYOCYTES

被引:67
作者
LIU, B [1 ]
WANG, LCH [1 ]
BELKE, DD [1 ]
机构
[1] UNIV ALBERTA,DEPT ZOOL,EDMONTON T6G 2E9,ALBERTA,CANADA
关键词
D O I
10.1016/0143-4160(91)90080-X
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
The effect of low temperature on the cytosolic free Ca2+ ([Ca2+]i) has been investigated in isolated ventricular myocytes from adult rats using the fluorescent probe Indo-1. The distribution of Indo-1 between the mitochondrial and cytoplasmic compartments was first determined in the isolated myocytes using the digitonin and Triton X-100 treatments. By subtracting the mitochondrial [Ca2+]i from the total [Ca2+]i measured with Indo-1, the average cytosolic [Ca2+]i was found to increase significantly (P < 0.05) from 139 nM to 255 and 297 nM when the temperature was decreased from 37-degrees-C to 15-degrees and 5-degrees-C, respectively. A marked increase in cytosolic [Ca2+]i to a new steady state level was observed when the membrane of myocytes was depolarized by 60 mM KCl; the average magnitude of increase being 110, 243 and 186 nM, at 37-degrees, 15-degrees and 5-degrees-C respectively. Our results support the hypothesis that the cardiac arrhythmia typically observed in the hypothermic rat is due to an increased cytosolic [Ca2+]i with decreasing body temperature.
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页码:11 / 18
页数:8
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