Blockade of cardiac sarcoplasmic reticulum K$^+$ channel by Ca$^2+$:
two-binding-site model of blockade.
Q. Liu, und H. Strauss. Biophys. J., 60 (1):
198--203(Juli 1991)
Zusammenfassung
Potassium countercurrent through the SR K$^+$ channel plays an
important role in Ca$^2+$ release from the SR. To see if Ca$^2+$
regulates the channel, we incorporated canine cardiac SR K$^+$
channel into lipid bilayers. Calcium ions present in either the SR
lumenal (trans) or cytoplasmic (cis) side blocked the cardiac SR
K$^+$ channel in a voltage-dependent manner. When Ca$^2+$
was present on both sides, however, the block appeared to be voltage
independent. A two-binding site model of blockade by an impermeant
divalent cation (Ca$^2+$) can explain this apparent contradiction.
Estimates of SR Ca$^2+$ concentration suggest that under physiological
conditions the cardiac SR K$^+$ channel is partially blocked
by Ca$^2+$ ions present in the lumen of the SR. The reduction
in lumenal Ca$^2+$ during Ca$^2+$ release could increase
K$^+$ conductance.
%0 Journal Article
%1 Liu_1991_198
%A Liu, Q. Y.
%A Strauss, H. C.
%D 1991
%J Biophys. J.
%K 1883938 Animals, Bilayers, Biological, Calcium, Centrifugation, Channels, Cytoplasm, Density Dogs, Electrophoresis, Gel, Gov't, Gradient, Heart, Lipid Mathematics, Membrane Models, Myocardium, P.H.S., Polyacrylamide Potassium Potentials, Research Reticulum, Sarcoplasmic Solubility, Support, U.S.
%N 1
%P 198--203
%T Blockade of cardiac sarcoplasmic reticulum K$^+$ channel by Ca$^2+$:
two-binding-site model of blockade.
%U http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=1883938
%V 60
%X Potassium countercurrent through the SR K$^+$ channel plays an
important role in Ca$^2+$ release from the SR. To see if Ca$^2+$
regulates the channel, we incorporated canine cardiac SR K$^+$
channel into lipid bilayers. Calcium ions present in either the SR
lumenal (trans) or cytoplasmic (cis) side blocked the cardiac SR
K$^+$ channel in a voltage-dependent manner. When Ca$^2+$
was present on both sides, however, the block appeared to be voltage
independent. A two-binding site model of blockade by an impermeant
divalent cation (Ca$^2+$) can explain this apparent contradiction.
Estimates of SR Ca$^2+$ concentration suggest that under physiological
conditions the cardiac SR K$^+$ channel is partially blocked
by Ca$^2+$ ions present in the lumen of the SR. The reduction
in lumenal Ca$^2+$ during Ca$^2+$ release could increase
K$^+$ conductance.
@article{Liu_1991_198,
abstract = {Potassium countercurrent through the SR {K}$^{+}$ channel plays an
important role in {C}a$^{2+}$ release from the SR. To see if {C}a$^{2+}$
regulates the channel, we incorporated canine cardiac SR {K}$^{+}$
channel into lipid bilayers. Calcium ions present in either the SR
lumenal (trans) or cytoplasmic (cis) side blocked the cardiac SR
{K}$^{+}$ channel in a voltage-dependent manner. When {C}a$^{2+}$
was present on both sides, however, the block appeared to be voltage
independent. A two-binding site model of blockade by an impermeant
divalent cation ({C}a$^{2+}$) can explain this apparent contradiction.
Estimates of SR {C}a$^{2+}$ concentration suggest that under physiological
conditions the cardiac SR {K}$^{+}$ channel is partially blocked
by {C}a$^{2+}$ ions present in the lumen of the SR. The reduction
in lumenal [{C}a$^{2+}$] during {C}a$^{2+}$ release could increase
{K}$^{+}$ conductance.},
added-at = {2009-06-03T11:20:58.000+0200},
author = {Liu, Q. Y. and Strauss, H. C.},
biburl = {https://www.bibsonomy.org/bibtex/25e6196c0457a86c22cc4e05ece1343fc/hake},
description = {The whole bibliography file I use.},
file = {Liu_1991_198.pdf:Liu_1991_198.pdf:PDF},
interhash = {b258d0de719a62edb25dac679175c34b},
intrahash = {5e6196c0457a86c22cc4e05ece1343fc},
journal = {Biophys. J.},
keywords = {1883938 Animals, Bilayers, Biological, Calcium, Centrifugation, Channels, Cytoplasm, Density Dogs, Electrophoresis, Gel, Gov't, Gradient, Heart, Lipid Mathematics, Membrane Models, Myocardium, P.H.S., Polyacrylamide Potassium Potentials, Research Reticulum, Sarcoplasmic Solubility, Support, U.S.},
month = Jul,
number = 1,
pages = {198--203},
pmid = {1883938},
timestamp = {2009-06-03T11:21:20.000+0200},
title = {Blockade of cardiac sarcoplasmic reticulum {K}$^{+}$ channel by {C}a$^{2+}$:
two-binding-site model of blockade.},
url = {http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=1883938},
volume = 60,
year = 1991
}