TY - JOUR
T1 - Leptin modulates electrophysiological characteristics and isoproterenol-induced arrhythmogenesis in atrial myocytes
AU - Lin, Yung Kuo
AU - Chen, Yao Chang
AU - Huang, Jen Hung
AU - Lin, Yenn Jiang
AU - Huang, Shiang Suo
AU - Chen, Shih Ann
AU - Chen, Yi Jen
PY - 2013/12/20
Y1 - 2013/12/20
N2 - 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.
AB - 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.
KW - Adipokines
KW - Atrial fibrillation
KW - Epicardial fat
KW - Leptin
KW - Obesity
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U2 - 10.1186/1423-0127-20-94
DO - 10.1186/1423-0127-20-94
M3 - Article
C2 - 24354396
AN - SCOPUS:84890463617
VL - 20
JO - Journal of Biomedical Science
JF - Journal of Biomedical Science
SN - 1021-7770
IS - 1
M1 - 94
ER -