Regulation of eosinophil membrane depolarization during NADPH oxidase activation

Jennifer L. Bankers-Fulbright, Gerald J. Gleich, Gail M. Kephart, Hirohito Kita, Scott M. O'Grady

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Protein kinase C (PKC) activation in human eosinophils increases NADPH oxidase activity, which is associated with plasma membrane depolarization. In this study, membrane potential measurements of eosinophils stimulated with phorbol ester (phorbol 12-myristate 13-acetate; PMA) were made using a cell-permeable oxonol membrane potential indicator, diBAC4(3). Within 10 minutes after PMA stimulation, eosinophils depolarized from -32.9±5.7 mV to +17.3±1.8 mV. The time courses of depolarization and proton channel activation were virtually identical. Blocking the proton conductance with 250 μM ZnCl2 (+43.0±4.2 mV) or increasing the proton channel activation threshold by reducing the extracellular pH to 6.5 (+44.4±1.4 mV) increased depolarization compared with PMA alone. Additionally, the protein kinase C (PKC) δ-selective blocker, rottlerin, inhibited PMA-stimulated depolarization, indicating that PKCδ was involved in regulating depolarization associated with eosinophil NADPH oxidase activity. Thus, the membrane depolarization that is associated with NADPH oxidase activation in eosinophils is sufficient to produce marked proton channel activation under physiological conditions.

Original languageEnglish (US)
Pages (from-to)3221-3226
Number of pages6
JournalJournal of cell science
Issue number15
StatePublished - Aug 1 2003


  • H channel
  • Membrane potential
  • NADPH oxidase
  • PKCδ
  • Superoxide

ASJC Scopus subject areas

  • Cell Biology


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