%0 Journal Article %1 Xu_2003_49085 %A Xu, Yanfang %A Tuteja, Dipika %A Zhang, Zhao %A Xu, Danyan %A Zhang, Yi %A Rodriguez, Jennifer %A Nie, Liping %A Tuxson, Holly R %A Young, J. Nilas %A Glatter, Kathryn A %A V�zquez, Ana E %A Yamoah, Ebenezer N %A Chiamvimonvat, Nipavan %D 2003 %J J. Biol. Chem. %K 13679367 Acid Acid, Amino Animals, Apamin, Base Blotting, Calcium-Activated, Channels, Cloning, DNA Data, Gov't, Heart, Homology, Humans, Male, Mice, Molecular Molecular, Non-P.H.S., P.H.S., Potassium Primers, Research Sequence Sequence, Support, U.S. Western, %N 49 %P 49085--49094 %R 10.1074/jbc.M307508200 %T Molecular identification and functional roles of a Ca$^2+$-activated K$^+$ channel in human and mouse hearts. %U http://dx.doi.org/10.1074/jbc.M307508200 %V 278 %X The repolarization phase of cardiac action potential is prone to aberrant excitation that is common in cardiac patients. Here, we demonstrate that this phase is markedly sensitive to Ca$^2+$ because of the surprising existence of a Ca$^2+$-activated K$^+$ currents in cardiac cells. The current was revealed using recording conditions that preserved endogenous Ca$^2+$ buffers. The Ca$^2+$-activated K$^+$ current is expressed differentially in atria compared with ventricles. Because of the significant contribution of the current toward membrane repolarization in cardiac myocytes, alterations of the current magnitude precipitate abnormal action potential profiles. We confirmed the presence of a small conductance Ca$^2+$-activated K$^+$ channel subtype (SK2) in human and mouse cardiac myocytes using Western blot analysis and reverse transcription-polymerase chain reaction and have cloned SK2 channels from human atria, mouse atria, and ventricles. Because of the marked differential expression of SK2 channels in the heart, specific ligands for Ca$^2+$-activated K$^+$ currents may offer a unique therapeutic opportunity to modify atrial cells without interfering with ventricular myocytes.

@article{Xu_2003_49085, abstract = {The repolarization phase of cardiac action potential is prone to aberrant excitation that is common in cardiac patients. Here, we demonstrate that this phase is markedly sensitive to {C}a$^{2+}$ because of the surprising existence of a {C}a$^{2+}$-activated {K}$^{+}$ currents in cardiac cells. The current was revealed using recording conditions that preserved endogenous {C}a$^{2+}$ buffers. The {C}a$^{2+}$-activated {K}$^{+}$ current is expressed differentially in atria compared with ventricles. Because of the significant contribution of the current toward membrane repolarization in cardiac myocytes, alterations of the current magnitude precipitate abnormal action potential profiles. We confirmed the presence of a small conductance {C}a$^{2+}$-activated {K}$^{+}$ channel subtype (SK2) in human and mouse cardiac myocytes using Western blot analysis and reverse transcription-polymerase chain reaction and have cloned SK2 channels from human atria, mouse atria, and ventricles. Because of the marked differential expression of SK2 channels in the heart, specific ligands for {C}a$^{2+}$-activated {K}$^{+}$ currents may offer a unique therapeutic opportunity to modify atrial cells without interfering with ventricular myocytes.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Xu, Yanfang and Tuteja, Dipika and Zhang, Zhao and Xu, Danyan and Zhang, Yi and Rodriguez, Jennifer and Nie, Liping and Tuxson, Holly R and Young, J. Nilas and Glatter, Kathryn A and V�zquez, Ana E and Yamoah, Ebenezer N and Chiamvimonvat, Nipavan}, biburl = {https://www.bibsonomy.org/bibtex/2b79e4434be34ee4b935f1f622f49fd4d/hake}, description = {The whole bibliography file I use.}, doi = {10.1074/jbc.M307508200}, file = {Xu_2003_49085.pdf:Xu_2003_49085.pdf:PDF}, interhash = {36d678022147ba00587a9fcbdf81f903}, intrahash = {b79e4434be34ee4b935f1f622f49fd4d}, journal = {J. Biol. Chem.}, keywords = {13679367 Acid Acid, Amino Animals, Apamin, Base Blotting, Calcium-Activated, Channels, Cloning, DNA Data, Gov't, Heart, Homology, Humans, Male, Mice, Molecular Molecular, Non-P.H.S., P.H.S., Potassium Primers, Research Sequence Sequence, Support, U.S. Western,}, month = Dec, number = 49, pages = {49085--49094}, pii = {M307508200}, pmid = {13679367}, timestamp = {2009-06-03T11:21:38.000+0200}, title = {Molecular identification and functional roles of a {C}a$^{2+}$-activated {K}$^{+}$ channel in human and mouse hearts.}, url = {http://dx.doi.org/10.1074/jbc.M307508200}, volume = 278, year = 2003 }