Fig. 7.

Disruption of the cardiomyocyte molecular clock reduces voltage-gated Na⁺ channel (Na_V1.5) levels and Na⁺ current (I_Na). A: Western blot data for Na_V1.5 in the hearts of iCSΔBmal1^+/+ and iCSΔBmal1^−/− mice at 58 h in darkness (n = 3/strain; *P < 0.05). B and C: representative families of currents (B) and the mean peak current-voltage (C) relations recorded from iCSΔBmal1^+/+ or iCSΔBmal1^−/− ventricular cardiomyocytes isolated from mice at 58 h in darkness. The gray and black lines show the robustness of a Boltzmann fit to data. D: iCSΔBmal1^−/− ventricular cardiomyocytes had a smaller maximal Na⁺ conductance (G_max). *P < 0.05.