%0 Journal Article %1 Pica_2002_1163 %A Picard, Luc %A C�t�, Karel %A Teijeira, Javier %A Greentree, David %A Rousseau, Eric %D 2002 %J J. Mol. Cell. Cardiol. %K 12392890 Animals, Atria, Cardiac, Channel Channels, Child, Conductivity, Elapid Electric Gating, Gov't, Heart Humans, Ion Magnesium, Myocytes, Non-U.S. Potassium Red, Research Reticulum, Ruthenium Ryanodine, Sarcoplasmic Sheep, Support, Venoms, %N 9 %P 1163--1172 %T Sarcoplasmic reticulum K$^+$ channels from human and sheep atrial cells display a specific electro-pharmacological profile. %U http://dx.doi.org/10.1006/jmcc.2002.2041 %V 34 %X It has recently been proposed that the Ca$^2+$ uptake by the SR is inhibited by blocking Cl$^-$ and/or K$^+$ movements across this intracellular membrane. We have characterised the functional and pharmacological profile of the SR K$^+$ channel derived from human and sheep atrial cells. Mammalian atrial SR preparations were subjected to (3)H-ryanodine binding assays, SDS-PAGE analysis and channel protein reconstitution into planar lipid bilayers. Assessment of (3)H-ryanodine binding on the SR Ca$^2+$ release channel revealed that it was inhibited by both Ruthenium Red and Mg$^2+$ with IC(50) values of 4.11 microM and 9.12 m M, respectively. In crude populations as well as in all SR-enriched fractions, activity of K$^+$ selective channels was recorded. This channel displayed a high conductance value of 193 and 185 pS for human and sheep preparations respectively. Gating and conducting behaviours of this channel were unaffected by the addition of up to 5m M 4-Aminopyridine (4-AP), 100 n M Iberiotoxin (IbTX), 10 microM E-4031 and 30 microM amiodarone. However, 100n M Dendrotoxin (gamma-DTX) largely increase the occurrence of the SR K$^+$ channel subconducting states without an effect on the main unitary conductance. These results demonstrate that the SR K$^+$ channel, present in all mammalian atrial SR membranes tested (as assessed by (3)H-ryanodine binding and its typical inhibition by ruthenium red and the magnesium), displays different properties than those classically described for cardiac sarcolemmal K$^+$ channels. Despite the fact that the biophysical properties of the SR K$^+$ channel are well known, its molecular identity remains to be ascertained.

@article{Pica_2002_1163, abstract = {It has recently been proposed that the {C}a$^{2+}$ uptake by the SR is inhibited by blocking {C}l$^{-}$ and/or {K}$^{+}$ movements across this intracellular membrane. We have characterised the functional and pharmacological profile of the SR {K}$^{+}$ channel derived from human and sheep atrial cells. Mammalian atrial SR preparations were subjected to [(3)H]-ryanodine binding assays, {SDS}-{PAGE} analysis and channel protein reconstitution into planar lipid bilayers. Assessment of [(3)H]-ryanodine binding on the SR {C}a$^{2+}$ release channel revealed that it was inhibited by both Ruthenium Red and {M}g$^{2+}$ with IC(50) values of 4.11 microM and 9.12 m M, respectively. In crude populations as well as in all SR-enriched fractions, activity of {K}$^{+}$ selective channels was recorded. This channel displayed a high conductance value of 193 and 185 pS for human and sheep preparations respectively. Gating and conducting behaviours of this channel were unaffected by the addition of up to 5m M 4-Aminopyridine (4-AP), 100 n M Iberiotoxin (Ib{TX}), 10 microM E-4031 and 30 microM amiodarone. However, 100n M Dendrotoxin (gamma-DTX) largely increase the occurrence of the SR {K}$^{+}$ channel subconducting states without an effect on the main unitary conductance. These results demonstrate that the SR {K}$^{+}$ channel, present in all mammalian atrial SR membranes tested (as assessed by [(3)H]-ryanodine binding and its typical inhibition by ruthenium red and the magnesium), displays different properties than those classically described for cardiac sarcolemmal {K}$^{+}$ channels. Despite the fact that the biophysical properties of the SR {K}$^{+}$ channel are well known, its molecular identity remains to be ascertained.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Picard, Luc and C�t�, Karel and Teijeira, Javier and Greentree, David and Rousseau, Eric}, biburl = {https://www.bibsonomy.org/bibtex/281fdfe48fa6830415327d03d2415ba10/hake}, description = {The whole bibliography file I use.}, file = {Pica_2002_1163.pdf:Pica_2002_1163.pdf:PDF}, interhash = {224bf840d76a5c8811b3c7020f12e9fd}, intrahash = {81fdfe48fa6830415327d03d2415ba10}, journal = {J. Mol. Cell. Cardiol.}, key = 188, keywords = {12392890 Animals, Atria, Cardiac, Channel Channels, Child, Conductivity, Elapid Electric Gating, Gov't, Heart Humans, Ion Magnesium, Myocytes, Non-U.S. Potassium Red, Research Reticulum, Ruthenium Ryanodine, Sarcoplasmic Sheep, Support, Venoms,}, month = Sep, number = 9, pages = {1163--1172}, pii = {S0022282802920419}, pmid = {12392890}, timestamp = {2009-06-03T11:21:25.000+0200}, title = {Sarcoplasmic reticulum {K}$^{+}$ channels from human and sheep atrial cells display a specific electro-pharmacological profile.}, url = {http://dx.doi.org/10.1006/jmcc.2002.2041}, volume = 34, year = 2002 }