Ca2+ activity in atrial myocytes
To investigate the inhibitory effect of isorhamnetin on
abnormal
diastolic SR Ca2+ activity, a Ca2+imaging study was performed using isolated atrial myocytes.
Isolated
atrial myocytes in the AngII group showed a significantly higher
frequency of diastolic
Ca2+ sparks in the presence of isoproterenol than in
the controls. In contrast, isorhamnetin treatment reversed AngII-induced
diastolic Ca2+ spark frequency (Fig. 2A-B).
Additionally, AngII treatment increased the Ca2+ spark
amplitude,
whereas
isorhamnetin treatment restored it (Fig. 2C). These findings indicate
that isorhamnetin has inhibitory effects on the vulnerability of AF by
alleviating diastolic aberrant SR Ca2+ activities.