AIMThe effects of angiotensin II on the changes of Ca2+ signal in cultured rat neonatal myocytes were investigated in order to reveal the localization and distribution of elementary Ca2+ signaling units.

METHODSThe 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.

RESULTSThe propagation of Ca2+ waves was observed in rest and angiotensin II stimulated cardiac myocytes. Calcium fluorescent intensity oscillated slightly in myocytes and the average intensity was much higher in the nucleus than in the cytosol, all of which could be magnified significantly by AngII (10(-6) mol/L). Ca2+ oscillation induced by Ang II was completely blocked by NO donor sodium nitroprusside. AngII evoked Ca2+ sparks close to the cell surface membrane, and couldn't be abolished by sodium nitroprusside.

CONCLUSIONThere are spatiotemporal dynamics of Ca2+ signaling patterns such as Ca2+ wave, Ca2+ spikes, Ca2+ oscillation and the whole cell Ca2+ transients induced by angiotensin II, which might play very important roles in cellular cardiac function.