Terada H, Hayashi H, Satoh H, Katoh H, Yamazaki N
Third Department of Internal Medicine, Hamamatsu University School of Medicine, Japan.
Biochem Biophys Res Commun. 1994 Sep 15;203(2):1050-6. doi: 10.1006/bbrc.1994.2288.
We have developed a new method to measure [Na+]i and Ca2+ transients of a beating cardiac myocyte using a Na(+)-sensitive fluorescent probe, sodium-binding benzofuran isophthalate (SBFI) and a Ca(2+)-sensitive fluorescent probe, fluo-3. There was no interaction between two probes, and the artifact due to contraction could be eliminated in the measurement of [Na+]i. [Na+]i in guinea pig ventricular myocytes stimulated at 1 Hz was 8.0 +/- 0.7mM. Strophanthidin (10 microM), initially, increased the amplitude and the basal level of Ca2+ transients in association with an increase in [Na+]i. When arrhythmias were induced, the amplitude of Ca2+ transients decreased while [Na+]i and the basal level of Ca2 transients continued to increase. These results suggested that the diastolic [Ca2+]i was closely related to [Na+]i. However, the systolic [Ca2+]i, which could be influenced by other factors, was dissociated from [Na+]i in the condition of Ca2+ overload.
我们开发了一种新方法，使用钠敏感荧光探针苯并呋喃异邻苯二甲酸钠（SBFI）和钙敏感荧光探针氟钙素-3来测量跳动心肌细胞的[Na+]i和Ca2+瞬变。两种探针之间没有相互作用，并且在[Na+]i的测量中可以消除由于收缩引起的伪影。以1Hz刺激的豚鼠心室肌细胞中的[Na+]i为8.0±0.7mM。毒毛花苷（10μM）最初会增加Ca2+瞬变的幅度和基础水平，并伴有[Na+]i的增加。当诱发心律失常时，Ca2+瞬变的幅度降低，而[Na+]i和Ca2+瞬变的基础水平继续升高。这些结果表明舒张期[Ca2+]i与[Na+]i密切相关。然而，在Ca2+过载的情况下，可能受其他因素影响的收缩期[Ca2+]i与[Na+]i分离。
