NPPB block of Ca++-activated Cl- currents in Xenopus oocytes

George Wu, Owen Hamill

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

NPPB (5-nitro-2-(3-phenylpropylamino)-benzoate), a mentoer of the novel class of Cl- channel blockers related to diphenylamine-2-carboxylate, was studied for its effect on the Ca++-activated Cl- current (ICl(Ca)) in frog (Xenopus laevis) oocytes. ICl(Ca) was activated by bath application of 5 mM Ca++ to oocytes that had been Ca++ permeabilized with the Ca++ ionophore A23187. In order to prevent the incativation of ICl(Ca)) that occurs with repetitive applications of Ca++, oocytes were also treated with H-7 (1,5-isoguinolinesulfonyl-1,2 methylpiperazine), an inhibitor of protein kinases. NPPB reversibly blocked both the fast transient (Ifast) and slow (Islow) components of ICl(Ca) with inhibition constants or 22 μM and 68 μM, respectively. NPPB block of ICl(Ca) was voltage dependent and potentiated by depolarization of the oocyte membrane. Our results indicate that NPPB is a potent blocker of the oocyte endogenous ICl(Ca) and may prove useful in the study of exogenously expressed Cl channels.

Original languageEnglish (US)
Pages (from-to)227-229
Number of pages3
JournalPflügers Archiv European Journal of Physiology
Volume420
Issue number2
DOIs
StatePublished - Feb 1992
Externally publishedYes

Fingerprint

Xenopus
Oocytes
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
Benzoates
Ionophores
Depolarization
Protein Kinase Inhibitors
Calcimycin
Xenopus laevis
Baths
Anura
Membranes
5-nitro-2-(3-phenylpropylamino)benzoic acid
Electric potential

Keywords

  • Ca-activated Cl current
  • NPPB
  • Xenopus oocyte

ASJC Scopus subject areas

  • Physiology

Cite this

NPPB block of Ca++-activated Cl- currents in Xenopus oocytes. / Wu, George; Hamill, Owen.

In: Pflügers Archiv European Journal of Physiology, Vol. 420, No. 2, 02.1992, p. 227-229.

Research output: Contribution to journalArticle

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