Figure 2: Tachypacing of HL-1 induced iNOS expression.

HL-1 cells were subjected to 4 Hz pacing for the indicated times. Bottom panel: the relative expression levels of iNOS and tubulin were quantified by densitometry and normalized to the control level, which was set at 1.0. Each value represents the mean ± SE of four independent experiments. One-way ANOVA with post hoc Tukey’s tests was applied for two groups and multiple comparisons. *P = 0.027 versus the controls. #P = 0.007 versus the controls.