Fig. 6.

Leptin reversibly increased action potential duration in rat ventricular myocytes. Representative action potentials were elicited by current clamp in a ventricular myocyte before (A), during (B), and after washout (C) of leptin (0.03 μg/ml). Leptin induced a late-plateau (LP) phase in another ventricular myocyte at the concentrations of 0.03 μg/ml (D) and 0.3 μg/ml (E), respectively. The vertical bar marks the height of the LP at t = 100ms. Dashed lines indicate resting membrane potentials. Leptin increased action potential duration (APD) at 50% repolarization (APD₅₀; F), APD₉₀ (G), and LP₁₀₀ (H). *Statistically significant compared with basal (F and G); #statistically significant compared with leptin at 0.03 μg/kg (G and H).