Marban E, Rink T J, Tsien R W, Tsien R Y
Nature. 1980 Aug 28;286(5776):845-50. doi: 10.1038/286845a0.
Direct measurements of free Ca2+ in heart cells are needed for an understanding of the regulation of contractility. We developed and used Ca2+ -sensitive microelectrodes with fine tips, stable properties and ample sensitivity to free Ca2+ in the sub-micromolar range. In quiescent ventricular muscle, measurements which passed tests for electrode sealing and cell viability gave a mean free Ca2+ concentration of 0.26 microM. During contractures, we recorded Ca2+ transients rising as high as 10 microM. In studying the effects of catecholamines on free Ca2+ and force, we found evidence that adrenaline can reduce myofibrillar Ca2+ sensitivity in intact heart muscle.
为了解心肌收缩性的调节机制，需要直接测量心肌细胞中的游离钙离子。我们开发并使用了尖端精细、性能稳定且对亚微摩尔范围内的游离钙离子具有足够灵敏度的钙离子敏感微电极。在静止的心室肌中，通过电极密封和细胞活力测试的测量结果显示，游离钙离子的平均浓度为0.26微摩尔。在挛缩过程中，我们记录到钙离子瞬变高达10微摩尔。在研究儿茶酚胺对游离钙离子和力量的影响时，我们发现有证据表明肾上腺素可以降低完整心肌中肌原纤维对钙离子的敏感性。
