Li Q, Altschuld R A, Stokes B T
Biochem Biophys Res Commun. 1987 Aug 31;147(1):120-6. doi: 10.1016/s0006-291x(87)80095-5.
Isolated rat myocytes incubated with the acetoxy methyl ester of fura 2 contained partially hydrolyzed esters, necessitating in vivo calibration of the signals obtained by fluorescence microscopy for calculation of pCa. Ionophores did not produce reliable R'max and R'min values in respiring myocytes, and elevated free calcium caused individual cells to hypercontract and burst. These difficulties were overcome by superfusion with a glucose-free buffer containing an inhibitor and an uncoupler of oxidative phosphorylation. R'max and R'min values obtained by ionophore treatment of deenergized myocytes were normalized to an in vitro calibration curve. Resting pCa derived from the individual curves averaged 6.9 for calcium-tolerant rod-shaped myocytes.
用fura 2的乙酰氧基甲酯孵育的离体大鼠心肌细胞含有部分水解的酯，因此需要对通过荧光显微镜获得的信号进行体内校准，以计算pCa。离子载体在呼吸的心肌细胞中不能产生可靠的R'max和R'min值，游离钙升高会导致单个细胞过度收缩并破裂。通过用含有氧化磷酸化抑制剂和解偶联剂的无葡萄糖缓冲液进行灌流克服了这些困难。通过离子载体处理去能心肌细胞获得的R'max和R'min值根据体外校准曲线进行标准化。从个体曲线得出的静息pCa，对于耐钙的杆状心肌细胞平均为6.9。
