Lack of "hemichannel" activity in insulin-producing cells

Eliana Scemes, Sabine Bavamian, Anne Charollais, David C. Spray, Paolo Meda

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Connexins and pannexins have been implicated in the formation of "hemichannels," which may account for the uptake and release of membrane-impermeant molecules in single cells. The in vivo existence of "hemichannels" and their protein composition is still debated. Investigations on these matters are complicated by the lack of adequate negative controls. In search for such essential controls, the authors have investigated transformed (MIN6 line) and primary insulin-producing cells. Here, the authors report that these cells, which express Cx36 and pannexin1, cannot be shown to display functional "hemichannels," as evaluated by (1) uptake of the membrane-impermeant tracer ethidium bromide, whether in the presence or absence of extracellular Ca2+, following stimulation of P2X7 receptors, and after exposure to hypotonic medium; and (2) lack of exocytosis-independent release of endogenous ATP. Moreover, electrophysiological recordings indicated the absence of carbenoxolone-sensitive pannexin1 currents evoked by membrane potentials above +30 mV. Thus, insulin-producing cells are expected to provide a useful tool in the further characterization of hemichannel composition, properties, and physiological relevance.

Original languageEnglish (US)
Pages (from-to)143-154
Number of pages12
JournalCell Communication and Adhesion
Volume15
Issue number1-2
DOIs
Publication statusPublished - May 1 2008

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Keywords

  • ATP
  • Cx36
  • Ethidium bromide
  • MIN6 cells
  • Pannexins
  • β-cells

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology

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