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.
%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
}