Na+ channel regulation by Ca2+/calmodulin and Ca2+/calmodulin-dependent protein kinase II in guinea-pig ventricular myocytes†

Endothelin-1 (ET-1) shows a positive inotropic effect on cardiac muscle. Although the L-type Ca2+ current ( ICa) is one of the important determinants of cardiac excitation-contraction coupling, the effect of ET-1 on the ICa is not always clear. The controversial results appear to be due to different patch-clamp methods. The present study measured the effect of ET-1 on the ICa of rat ventricular myocytes using the perforated patch-clamp technique. The holding potential was set to −40 mV, and depolarization was applied every 10 s. ET-1 (10 nM) increased the ICa in a monophasic manner. The current reached a steady state 15 min after the application of ET-1, when the measurement was done. Endothelin receptor subtype expression was also investigated using Western immunoblotting. ETA-receptor protein was expressed, but ETB-receptor protein was not expressed, in the cell membranes of rat ventricular myocytes. The effect of ET-1 on the ICa was inhibited by a selective ETA-receptor antagonist, BQ-123, but not by a selective ETB-receptor antagonist, BQ-788. The effect was inhibited by protein kinase C (PKC) inhibitor chelerythrine and Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93, but not by its inactive analog KN-92. The effect of ET-1 was also blocked by another CaMKII inhibitor, autocamtide-2-related inhibitory peptide. These results suggest that ET-1 increases the ICa via the ETA-receptor-PKC-CaMKII pathway.

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Ca 2+ /Calmodulin-Dependent Protein Kinase II Phosphorylation of Ryanodine Receptor Does Affect Calcium Sparks in Mouse Ventricular Myocytes

Circulation Research ◽

10.1161/01.res.0000236756.06252.13 ◽

2006 ◽

Vol 99 (4) ◽

pp. 398-406 ◽

Cited By ~ 188

Author(s):

Tao Guo ◽

Tong Zhang ◽

Ruben Mestril ◽

Donald M. Bers

Keyword(s):

Protein Kinase ◽

Ryanodine Receptor ◽

Ventricular Myocytes ◽

Calcium Sparks ◽

Dependent Protein Kinase ◽

Protein Kinase Ii ◽

Dependent Protein

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Modulation of late sodium current by Ca2+-calmodulin-dependent protein kinase II, protein kinase C and Ca2+during hypoxia in rabbit ventricular myocytes

Experimental Physiology ◽

10.1113/ep085990 ◽

2017 ◽

Vol 102 (7) ◽

pp. 818-834 ◽

Cited By ~ 7

Author(s):

Chen Fu ◽

Jie Hao ◽

Mengliu Zeng ◽

Yejia Song ◽

Wanzhen Jiang ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Ventricular Myocytes ◽

Sodium Current ◽

Dependent Protein Kinase ◽

Late Sodium Current ◽

Kinase C ◽

Protein Kinase Ii ◽

Dependent Protein ◽

Rabbit Ventricular Myocytes

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Sevoflurane Protects Ventricular Myocytes against Oxidative Stress-induced Cellular Ca2+ Overload and Hypercontracture

Anesthesiology ◽

10.1097/aln.0b013e318292ee52 ◽

2013 ◽

Vol 119 (3) ◽

pp. 606-620 ◽

Cited By ~ 23

Author(s):

Akiko Kojima ◽

Hirotoshi Kitagawa ◽

Mariko Omatsu-Kanbe ◽

Hiroshi Matsuura ◽

Shuichi Nosaka

Keyword(s):

Oxidative Stress ◽

Protein Kinase ◽

Reperfusion Injury ◽

Ventricular Myocytes ◽

Concomitant Administration ◽

Resting Potential ◽

Dependent Protein Kinase ◽

Transport Pathways ◽

Protein Kinase Ii ◽

Dependent Protein

Abstract Background: Oxidative stress is implicated in pathogenesis of cardiac reperfusion injury, characterized by cellular Ca2+ overload and hypercontracture. Volatile anesthetics protect the heart against reperfusion injury primarily by attenuating Ca2+ overload. This study investigated electrophysiological mechanisms underlying cardioprotective effects of sevoflurane against oxidative stress-induced cellular injury. Methods: The cytosolic Ca2+ levels and cell morphology were assessed in mouse ventricular myocytes, using confocal fluo-3 fluorescence imaging, whereas membrane potentials and L-type Ca2+ current (ICa,L) were recorded using whole-cell patch-clamp techniques. Phosphorylation of Ca2+/calmodulin-dependent protein kinase II was examined by Western blotting. Results: Exposure to H2O2 (100 μm) for 15 min evoked cytosolic Ca2+ elevation and hypercontracture in 56.8% of ventricular myocytes in 11 experiments, which was partly but significantly reduced by nifedipine, tetracaine, or SEA0400. Sevoflurane prevented H2O2-induced cellular Ca2+ overload in a concentration-dependent way (IC50 = 1.35%). Isoflurane (2%) and desflurane (10%) also protected ventricular myocytes by a degree similar to sevoflurane (3%). Sevoflurane suppressed H2O2-induced electrophysiological disturbances, including early afterdepolarizations, voltage fluctuations in resting potential, and abnormal automaticities. H2O2 significantly enhanced ICa,L by activating Ca2+/calmodulin-dependent protein kinase II, and subsequent addition of sevoflurane, isoflurane, or desflurane similarly reduced ICa,L to below baseline levels. Phosphorylated Ca2+/calmodulin-dependent protein kinase II increased after 10-min incubation with H2O2, which was significantly prevented by concomitant administration of sevoflurane. Conclusions: Sevoflurane protected ventricular myocytes against H2O2-induced Ca2+ overload and hypercontracture, presumably by affecting multiple Ca2+ transport pathways, including ICa,L, Na+/Ca2+ exchanger and ryanodine receptor. These actions appear to mediate cardioprotection against reperfusion injury associated with oxidative stress.

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