Hohl C M, Altschuld R A
Department of Physiological Chemistry, Ohio State University, Columbus 43210.
Am J Physiol. 1991 Mar;260(3 Pt 1):C383-91. doi: 10.1152/ajpcell.1991.260.3.C383.
Isolated adult canine ventricular myocytes incubated in the absence of glucose with the respiratory inhibitor rotenone retained 67% of ATP (control, 26.0 +/- 0.9 nmol/mg protein) during 3-h incubation, yet phosphocreatine fell to 23% of initial content. Lactate production proceeded at a constant rate of 5 nmol.mg-1.min-1 in rotenone-treated glucose-free myocytes. A 36% decline in rod-shaped cells and an increase in percent 22Na permeation from 37% in aerobic cells (approximately 13 mM intracellular sodium) to 68% in rotenone-treated glucose-free myocytes paralleled the loss of ATP. Total exchangeable calcium was maintained at control aerobic levels. Exposure of canine cells to 3-h hypoxia in the absence of glucose followed by 5-min reoxygenation resulted in a 73% decrease in ATP, a rise in calcium from 3.3 +/- 0.2 to 6.6 +/- 1.6 nmol/mg, and an increase in 22Na permeation to 111%. Under these conditions the number of rod-shaped myocytes declined by 77%, with corresponding increases in viable contracted and hypercontracted myocytes. The response of canine myocytes to severe hypoxia and reaeration contrasts greatly to earlier studies using adult rat cardiac myocytes [see Hohl et al. Am. J. Physiol. 242 (Heart Circ. Physiol. 11): H1022-H1030, 1982]. Species differences with respect to basal metabolism, rates of ATP production and degradation, and regulation of cation movements are most likely responsible for the observed differences.
在无葡萄糖且存在呼吸抑制剂鱼藤酮的条件下孵育的成年犬心室肌细胞，在3小时孵育期间保留了67%的ATP（对照组为26.0±0.9 nmol/mg蛋白质），然而磷酸肌酸降至初始含量的23%。在经鱼藤酮处理的无葡萄糖肌细胞中，乳酸产生以5 nmol·mg⁻¹·min⁻¹的恒定速率进行。杆状细胞减少36%，22Na渗透率从需氧细胞中的37%（细胞内钠约13 mM）增加到经鱼藤酮处理的无葡萄糖肌细胞中的68%，这与ATP的损失平行。可交换钙总量维持在对照需氧水平。犬细胞在无葡萄糖条件下暴露于3小时缺氧，随后再氧合5分钟，导致ATP减少73%，钙从3.3±0.2增加到6.6±1.6 nmol/mg，22Na渗透率增加到111%。在这些条件下，杆状肌细胞数量减少77%，存活的收缩和过度收缩肌细胞相应增加。犬肌细胞对严重缺氧和再氧合的反应与早期使用成年大鼠心肌细胞的研究形成极大对比[见Hohl等人，《美国生理学杂志》242（心脏循环生理学11）：H1022 - H1030，1982]。关于基础代谢、ATP产生和降解速率以及阳离子运动调节的物种差异很可能是观察到的差异的原因。
