AIMTo investigate the biological mechanism of the dynamic changes of living myocardial nuclear calcium which was isolated from aerobic exercised rats.

METHODSAcutely isolated myocardial cells were incubated with STDBT and Fluo-3Ca2+ fluorescent indicator. The changes of the fluorescence signal of free calcium were measured by laser scanning confocal microscope (LSCM).

RESULTSThe fluorescence of the ventricular myocardium cell was weak which was incubated with nucleus specific Ca2+ fluorescent probe STDBT-AM, transverse striation and transverse tubules was looked ambiguous. The most significant fluorescence intensity was distributed in the place of nucleus, bottle green was observed and the borderline of nuclear membrane. It was showed that STDBT could though cytoplasm and specifically clustered in nucleus and characterized by targeting to the distribution of nucleus. Compared with control group, aerobic exercise group had the same characteristic of the change of the basic and peak value of [Ca2+]n. When isoproterenol was added, the [Ca2+]n of aerobic exercise group was increased significantly, its change rate was 33.3412% (P < 0.01). Before and after added isoproterenol, myocardial cell's [Ca2+]n changed significantly. After added isoproterenol, the [Ca2+]n of aerobic exercise group was increased significantly and the change rate was 33.224%.

CONCLUSIONThis article firstly studied the changes of living myocardial nuclear calcium and discussed the transport of the [Ca2+]n of myocardial nuclear which was isolated from aerobic exercised rats; proved that aerobic exercise could increase its level of [Ca2+]n significantly, isoproterenol could increase the level of [Ca2+]n and decrease the level of [Ca2+]i. Myocardial nuclear is one of calcium stores of myocardial cell, aerobic exercise could impact on the modulation of myocardial cell.