CLOCK rescues cell survival in cardiac myocytes. (A), cell viability of ventricular myocytes stained with vital dyes calcein-AM and ethidium-homodimer-1 to demark the live (green) and dead (red) cells in the absence and presence of CLOCK WT or CLOCK mutants, bar: 100 μm, histogram represents quantitative data for Panel A, data are expressed as mean ± SEM. *p < 0.05; **p < 0.01, n = 3 independent myocyte isolations, counting > 200 for each condition tested