[Effects of angiotensin II on Ca2+ signal in cultured rat cardiac myocytes revealed by confocal laser scanning microscopy].

Aim: The effects of angiotensin Ⅱon the changes of Ca~(2+) signal in cultured rat neonatal myocytes were investigated in order to reveal the localization and distribution of elementary Ca~(2+) signaling units. Methods: The cultured neonate rat myocytes were treated with angiotensin Ⅱ, and calcium signal was detected using confocal laser scanning microscopy and fluo-4/AM calcium probe. Results: The propagation of Ca~(2+) waves was observed in rest and angiotensin Ⅱstimulated cardiac myocytes. Calcium fluorescent intensity oscillated slightly in myocytes and the average intensity was much higher in the nucleus than in the cytosole, all of which could be magnified significantly by AngⅡ(10~(-6) mol/L). Ca~(2+) oscillation induced by AngⅡ was completely blocked by NO donor sodium nitroprusside. AngⅡ evoked Ca~(2+) sparks close to the cell surface membrane, and couldn't be abolished by sodium nitroprusside. Conclusion: There are spatiotemporal dynamics of Ca~(2+) signaling patterns such as Ca~(2+) wave, Ca~(2+) spikes, Ca~(2+) oscillation and the whole cell Ca~(2+) transients induced by angiotensin Ⅱ, which might play very important roles in cellular cardiac function.