Adenosine triphosphate activates ion permeabilities in biliary epithelial cells

James M. McGill, Srisaila Basavappa, Allen W. Mangel, Gayle H. Shimokura, John P. Middleton, J. Gregory Fitz

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

Background/Aims: The biliary epithelium contributes to bile formation through absorption and secretion of fluid and electrolytes. The effects of extracellular nucleotides on membrane ion transport were assessed in isolated bile duct cells from rats and Mz-ChA-1 cells from a human cholangiocarcinoma. Methods: The rates of efflux of 125I and 86Rb were used to assess membrane CI- and K+ permeabilities, respectively. Patch clamp recordings of whole cell currents were used to evaluate the properties of adenosine triphosphate (ATP)-activated currents. Results: Purinergic receptor agonists ATP and uridine triphosphate stimulated 125I and 86Rb efflux about twofold above basal levels. The effects were reproduced by a nonhydrolyzable analogue of ATP (adenosine 5′-O-[3-thiophosphate]) and were unaffected by an adenosine receptor blocker xanthine amine congener. 125I efflux was also stimulated by adenosine and its receptor agonists 5′-N-ethylcar-boxamidoadenosine, N6-(2-phenylisopropyl)adenosine; these effects were inhibited by xanthine amine congener, suggesting a separate adenosine receptor. ATP, adenosine 5′-O-(3-thiophosphate), and uridine triphosphate each stimulated release of Ca2+ from intracellular stores, whereas adenosine had no effect. In whole cell recordings of Mz-ChA-1 cells, ATP activated an early transient outward current consistent with a K+ conductance and a later, sustained inward current consistent with a CI- conductance. Conclusions: Biliary cells possess at least two classes of nucleotide receptors that modulate membrane ion permeability through Ca2+-dependent and -independent pathways, and ATP may be involved in the regulation of biliary secretion.

Original languageEnglish (US)
Pages (from-to)236-243
Number of pages8
JournalGastroenterology
Volume107
Issue number1
StatePublished - 1994

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Permeability
Adenosine Triphosphate
Epithelial Cells
Adenosine
Ions
Uridine Triphosphate
Purinergic P1 Receptors
Xanthine
Patch-Clamp Techniques
Amines
Membranes
Nucleotides
Purinergic Agonists
Purinergic P1 Receptor Agonists
Fluids and Secretions
Cholangiocarcinoma
Ion Transport
Bile Ducts
Bile
Electrolytes

ASJC Scopus subject areas

  • Gastroenterology

Cite this

McGill, J. M., Basavappa, S., Mangel, A. W., Shimokura, G. H., Middleton, J. P., & Fitz, J. G. (1994). Adenosine triphosphate activates ion permeabilities in biliary epithelial cells. Gastroenterology, 107(1), 236-243.

Adenosine triphosphate activates ion permeabilities in biliary epithelial cells. / McGill, James M.; Basavappa, Srisaila; Mangel, Allen W.; Shimokura, Gayle H.; Middleton, John P.; Fitz, J. Gregory.

In: Gastroenterology, Vol. 107, No. 1, 1994, p. 236-243.

Research output: Contribution to journalArticle

McGill, JM, Basavappa, S, Mangel, AW, Shimokura, GH, Middleton, JP & Fitz, JG 1994, 'Adenosine triphosphate activates ion permeabilities in biliary epithelial cells', Gastroenterology, vol. 107, no. 1, pp. 236-243.
McGill JM, Basavappa S, Mangel AW, Shimokura GH, Middleton JP, Fitz JG. Adenosine triphosphate activates ion permeabilities in biliary epithelial cells. Gastroenterology. 1994;107(1):236-243.
McGill, James M. ; Basavappa, Srisaila ; Mangel, Allen W. ; Shimokura, Gayle H. ; Middleton, John P. ; Fitz, J. Gregory. / Adenosine triphosphate activates ion permeabilities in biliary epithelial cells. In: Gastroenterology. 1994 ; Vol. 107, No. 1. pp. 236-243.
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