Leptin modulates electrophysiological characteristics and isoproterenol-induced arrhythmogenesis in atrial myocytes

Background: obesity is an important risk factor for atrial fibrillation (af). leptin is an important adipokine. however,it is not clear whether leptin directly modulates the electrophysiological characteristics of atrial myocytes. results: whole cell patch clamp and indo-1 fluorescence were used to record the action potentials (aps) and ionic currents in isolated rabbit left atrial (la) myocytes incubated with and without (control) leptin (100 nm) for 1 h to investigate the role of leptin on atrial electrophysiology. leptin-treated la myocytes (n = 19) had longer 20% of ap duration (28 ± 3 vs. 21 ± 2 ms,p < 0.05),but similar 50% of ap duration (51 ± 4 vs. 50 ± 3 ms,p > 0.05),and 90% of ap duration (89 ± 5 vs. 94 ± 4 ms,p > 0.05),as compared to the control (n = 22). in the presence of isoproterenol (10 nm),leptin-treated la myocytes (n = 21) showed a lower incidence (19% vs. 54.2%,p < 0.05) of delayed afterdepolarization (dad) than the control (n = 24). leptin-treated la myocytes showed a larger sodium current,but a smaller ultra-rapid delayed rectifier potassium current,and sodium-calcium exchanger current than the control. leptin-treated and control la myocytes exhibited a similar late sodium current,inward rectifier potassium current,transient outward current and l-type calcium current. in addition,the leptin-treated la myocytes (n = 38) exhibited a smaller intracellular ca§ssup§2+§esup§ transient (0.21 ± 0.01 vs. 0.26 ± 0.01 r410/485,p < 0.05) and sarcoplasmic reticulum ca§ssup§2+§esup§ content (0.35 ± 0.02 vs. 0.43 ± 0.03 r410/485,p < 0.05) than the control la myocytes (n = 42). conclusions: leptin regulates the la electrophysiological characteristics and attenuates isoproterenol-induced arrhythmogenesis. © 2013 lin et al.; licensee biomed central ltd.