Effects of extracellular ATP on ion transport and [Ca2+](i) in Mongolian gerbil middle ear epithelium

Masayuki Furukawa, Katsuhisa Ikeda, Mutsuo Yamaya, Takeshi Oshima, Hidetada Sasaki, Tomonori Takasaka

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22 Citations (Scopus)

Abstract

The present study investigates the effects of ATP on ion transport and Ca2+ mobilization in primary cultures of gerbil middle ear epithelium. Extracellular ATP and other nucleotides elicited a transient increase in short-circuit current (I(sc)) in a dose-dependent manner. The rank order of potency in I(sc) responses corresponded with the sequence of the P(2u) purinergic receptor when applied to the mucosal or the basolateral side. Extracellular ATP induced a rise in the intracellular Ca2+ concentration ([Ca2+](i)) in a dose-dependent manner. A similar rank order of potency in the ATP-induced increases in [Ca2+](i) was observed. The time courses of the [Ca2+](i) responses induced by ATP closely paralleled those of the I(sc) responses. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester greatly reduced the increase in the I(sc) and [Ca2+](i) responses to ATP. Diphenylamine-2-carboxylate, 4,4'-diisothiocyanostilbene- 2,2'-disulfonic acid, quinidine, and Ba2+ significantly blocked the ATP- stimulated I(sc). Glibenclamide had no effect on the ATP-stimulated I(sc). These results are consistent with the hypothesis that extracellular ATP and other nucleotides induce Cl- secretion across the apical membrane in cultured gerbil middle ear epithelium by activation of the apical Cl- channels via multiple modes of regulation.

Original languageEnglish
Pages (from-to)C827-C836
JournalAmerican Journal of Physiology - Cell Physiology
Volume272
Issue number3 41-3
DOIs
Publication statusPublished - 1997 Mar

Keywords

  • Ussing chambers
  • cell culture
  • chloride secretion
  • short-circuit current

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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