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作者分析灌流液pH值改变,在伴有或不伴有游离Ca~(2+)活度([Ca~(2+)])改变的条件下,对离体心肌动作电位的影响.灌流液pH值改变可影响钙的结合,进而改变游离[Ca~(2+)].分离豚鼠右室,截取4mm直径肌块,以Kreb-Ringer(K-R)碳酸氢盐、磷酸盐缓冲溶液和含4-(2-羟乙基)-1-吡哌乙磺酸的Hepes有机缓冲溶液灌流之.在对照(充以含5%CO_2的氧气)、酸性(含12%CO_2)和碱性(含0%CO_2)的条件下,给予适当电刺激(强度为阈值3～4倍,脉冲的宽度为2ms而频率为150/min),并由细胞内微电极记录内膜下单个心肌细胞的动作电位.细胞外游离[Ca~(2+)]以钙离子选择性电极测定,可溶性钙总浓度则以超滤和光谱分析技术测定.K-R溶液内总[CaCl_2]控制在2.5mM,于碱性(pH8.19)、对照(pH7.44)和酸性(pH6.97)的条件
The authors analyzed the changes in perfusate pH, with or without free Ca2 + activity ([Ca2 +]) changes in the conditions of the isolated myocardial action potential. Perfusion Changes in pH can affect the binding of calcium, which in turn changes the free [Ca 2+]. The right ventricle of the guinea pig is isolated and a 4 mm diameter muscle segment is taken. Kreb-Ringer (KR) bicarbonate, phosphate buffered saline, - (2-hydroxyethyl) -1 -piperidene sulphonate in the control (filled with 5% CO 2 in oxygen), acidic (containing 12% CO 2) and alkaline % CO_2), the appropriate electrical stimulation (3 ~ 4 times the intensity, pulse width 2ms and frequency 150 / min) was given. The action potential of intima single cardiomyocytes was recorded by intracellular microelectrode. The extracellular free [Ca2 +] was determined by calcium ion selective electrode and the total concentration of soluble calcium was determined by ultrafiltration and spectroscopic analysis.The total [CaCl2] in KR solution was controlled at 2.5mM, .19), control (pH 7.44) and acidic (pH 6.97)