TY - JOUR
T1 - Inhibition of a cardiac sarcoplasmic reticulum chloride channel by tamoxifen
AU - Beca, Sanja
AU - Pavlov, Evgeny
AU - Kargacin, Margaret E.
AU - Aschar-Sobbi, Roozbeh
AU - French, Robert J.
AU - Kargacin, Gary J.
PY - 2008/10
Y1 - 2008/10
N2 - Anion and cation channels present in the sarcoplasmic reticulum (SR) are believed to be necessary to maintain the electroneutrality of SR membrane during Ca2+ uptake by the SR Ca2+ pump (SERCA). Here we incorporated canine cardiac SR ion channels into lipid bilayers and studied the effects of tamoxifen and other antiestrogens on these channels. A Cl- channel was identified exhibiting multiple subconductance levels which could be divided into two primary conductance bands. Tamoxifen decreases the time the channel spends in its higher, voltage-sensitive band and the mean channel current. The lower, voltage-insensitive, conductance band is not affected by tamoxifen, nor is a K+ channel present in the cardiac SR preparation. By examining SR Ca2+ uptake, SERCA ATPase activity, and SR ion channels in the same preparation, we also estimated SERCA transport current, SR Cl- and K+ currents, and the density of SERCA, Cl -, and K+ channels in cardiac SR membranes.
AB - Anion and cation channels present in the sarcoplasmic reticulum (SR) are believed to be necessary to maintain the electroneutrality of SR membrane during Ca2+ uptake by the SR Ca2+ pump (SERCA). Here we incorporated canine cardiac SR ion channels into lipid bilayers and studied the effects of tamoxifen and other antiestrogens on these channels. A Cl- channel was identified exhibiting multiple subconductance levels which could be divided into two primary conductance bands. Tamoxifen decreases the time the channel spends in its higher, voltage-sensitive band and the mean channel current. The lower, voltage-insensitive, conductance band is not affected by tamoxifen, nor is a K+ channel present in the cardiac SR preparation. By examining SR Ca2+ uptake, SERCA ATPase activity, and SR ion channels in the same preparation, we also estimated SERCA transport current, SR Cl- and K+ currents, and the density of SERCA, Cl -, and K+ channels in cardiac SR membranes.
KW - Anion channel
KW - Calcium transport
KW - Cation channel
KW - Electrophysiology
KW - Fluorescence
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U2 - 10.1007/s00424-008-0510-9
DO - 10.1007/s00424-008-0510-9
M3 - Article
C2 - 18458943
AN - SCOPUS:52549098388
VL - 457
SP - 121
EP - 135
JO - Pflugers Archiv fur die gesamte Physiologie des Menschen und der Tiere
JF - Pflugers Archiv fur die gesamte Physiologie des Menschen und der Tiere
SN - 0031-6768
IS - 1
ER -