Mechanisms underlying the modulation of L-type Ca2+ channel by hydrogen peroxide in guinea pig ventricular myocytes

• Published in: The journal of physiological sciences 2013-11, Vol.63 (6), p.419-426
• Main Authors: Yang, Lei, Xu, Jianjun, Minobe, Etsuko, Yu, Lifeng, Feng, Rui, Kameyama, Asako, Yazawa, Kazuto, Kameyama, Masaki
• Format: Article
• Language: English
• Subjects: Animals; Benzylamines - pharmacology; Calcium Channels, L-Type - drug effects; Calcium Channels, L-Type - physiology; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - antagonists & inhibitors; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - physiology; Cysteine - metabolism; Female; Guinea Pigs; Hydrogen Peroxide - pharmacology; Myocytes, Cardiac - drug effects; Myocytes, Cardiac - physiology; Original Paper; Patch-Clamp Techniques; Sulfonamides - pharmacology
• ISSN: 1880-6546; 1880-6562
• DOI: 10.1007/s12576-013-0279-2

Although Cav1.2 Ca(2+) channels are modulated by reactive oxygen species (ROS), the underlying mechanisms are not fully understood. In this study, we investigated effects of hydrogen peroxide (H2O2) on the Ca(2+) channel using a patch-clamp technique in guinea pig ventricular myocytes. Externally applied H2O2 (1 mM) increased Ca(2+) channel activity in the cell-attached mode. A specific inhibitor of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) KN-93 (10 μM) partially attenuated the H2O2-mediated facilitation of the channel, suggesting both CaMKII-dependent and -independent pathways. However, in the inside-out mode, 1 mM H2O2 increased channel activity in a KN-93-resistant manner. Since H2O2-pretreated calmodulin did not reproduce the H2O2 effect, the target of H2O2 was presumably assigned to the Ca(2+) channel itself. A thiol-specific oxidizing agent mimicked and occluded the H2O2 effect. These results suggest that H2O2 facilitates the Ca(2+) channel through oxidation of cysteine residue(s) in the channel as well as the CaMKII-dependent pathway.