Blockade of Ca2+-dependent Cl current in xenopus oocytes by Cl channel blockers and antimalarial drugs

Luo Lu, Diane Markakis, William B Guggino

Research output: Contribution to journalArticle

Abstract

Effects of Cl channel blockers and antimalarial drugs on the Ca2’-dependent Cl' current in Xenopus oocytes were studied using a two-microelectrode voltage-clamp technique. Chloride channel blockers, such as stilbene disulfonic acids and carboxylic acids, inhibit the Cl current in oocytes. The calculated half-inhibitory concentrations (IC50) of these blockers on the oocyte Cl current demonstrate an order of potency of 4, 4'-diisothio- cyanatostilbene-2, 2'-disulfonic acid > anthracene-9-carboxylic acid > diphenylamine-2- carboxylic acid > indanyloxyacetic acid. This is different from the potency observed in the outwardly rectifying Cl" channels of epithelial cells. The blocking effect of these Cl" channel blockers on the Ca2^-dependent Cl" current in oocytes was observed to be stronger at positive membrane potentials. In addition, various antimalarial drugs, such as quinine’s derivatives and artesunate, inhibit the Ca2+-dependent Cl" current in oocytes. These inhibitory' effects on cytoplasmic membrane Cl" channels may be responsible for the pharmacological action and toxic side effects of these compounds.

Original languageEnglish (US)
Pages (from-to)251-262
Number of pages12
JournalCellular Physiology and Biochemistry
Volume1
Issue number5-6
DOIs
Publication statusPublished - 1991

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Keywords

  • Antimalarial drugs
  • Ca<sup>2+</sup>-dependent cl<sup>−</sup> current
  • Cl<sup>−</sup>channel blocker
  • Quinine
  • Voltage clamp
  • Xenopus oocytes

ASJC Scopus subject areas

  • Physiology

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