Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York 10032.
J Gen Physiol. 1968 Sep 1;52(3):666-81. doi: 10.1085/jgp.52.3.666.
The intracellular sodium concentration reported for young, embryonic chick hearts is extremely high and decreases progressively throughout the embryonic period, reaching a value of 43 mM immediately before hatching. This observation suggested that the ionic basis for excitation in embryonic chick heart may differ from that responsible for electrical activity of the adult organ. This hypothesis was tested by recording transmembrane resting and action potentials on hearts isolated from 6-day and 19-day chick embryos and varying the extracellular sodium and potassium concentrations. The results show that for both young and old embryonic cardiac cells the resting potential depends primarily on the extracellular potassium concentration and the amplitude and rate of rise of the action potential depend primarily on the extracellular sodium concentration.
年轻的鸡胚心脏细胞内钠离子浓度极高，并且在胚胎期内逐渐降低，在孵化前达到 43mM。这一观察结果表明，鸡胚心脏兴奋的离子基础可能与成人心脏电活动的离子基础不同。这一假说通过记录来自 6 天和 19 天鸡胚的心脏的跨膜静息和动作电位，改变细胞外钠离子和钾离子浓度来验证。结果表明，对于年轻和年老的胚胎心肌细胞，静息电位主要取决于细胞外钾离子浓度，而动作电位的幅度和上升速率主要取决于细胞外钠离子浓度。
