Inhibition of a cardiac sarcoplasmic reticulum chloride channel by tamoxifen

Sanja Beca, Evgeny Pavlov, Margaret E. Kargacin, Roozbeh Aschar-Sobbi, Robert J. French, Gary J. Kargacin

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)121-135
Number of pages15
JournalPflugers Archiv European Journal of Physiology
Issue number1
StatePublished - Oct 2008


  • Anion channel
  • Calcium transport
  • Cation channel
  • Electrophysiology
  • Fluorescence

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)


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