Atorvastatin blocks increased L-type Ca^2＋ current and cell injury elicited by angiotensin II via inhibiting oxide stress

The L-type Ca^2＋ current （ICa,L） plays a crucial role in shaping action potential and is involved in cardiac arrhythmia. Statins have been demonstrated to contribute to anti-apoptotic and anti-arrhythmic effects in the heart. Here, we examined whether atorvastatin regulates the ICa,L and cell injury induced by angiotensin II （Angll） as well as the putative intracellular cascade responsible for the effects. Cultured neonatal rat ventricular myocytes were incubated with Angll for 24 h, and then cell injury and expression levels of Nox2/gp91^phox, p47^phox and Car1.2 were analyzed. In addition,Ica,L was recorded using the whole-cell patch-clamp technique, and mechanisms of atorvastatin actions were also investigated. It was found that the number of apoptotic cardiomyocytes was increased and cell viability was significantly decreased after Angll administration. Angll also augmented the expressions of Nox2/gp91^phox and p47^phox compared with control cardiomyocytes. Exposure to Angll evoked ICa,L in a voltage-dependent manner without affecting the/-V relationship. In addition, Angll enhanced membrane Cav1.2 expression. These effects were abolished in the presence of the reactive oxygen species （ROS） scavenger, manganese （III）-tetrakis 4-benzoic acid porphyrin [Mn（III） TBAP], or the 3-hydroxy-3-methylglutaryI-CoA reductase inhibitor, atorvastatin. These results sug- gested that atorvastatin mediates cardioprotection against arrhythmias and cell injury by controlling the AngII-ROS cascade.