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Hyperoxia induces alkalinization and dome formation in MDCK epithelial cells
Journal article

Hyperoxia induces alkalinization and dome formation in MDCK epithelial cells

  • Dreher, D. Respiratory Division, University Hospital, Geneva, Switzerland.
  • Rochat, T. Respiratory Division, University Hospital, Geneva, Switzerland.
Published in:
  • American Journal of Physiology-Cell Physiology. - American Physiological Society. - 1992, vol. 262, no. 2, p. C358-C364
English We observed that confluent Madin-Darby canine kidney (MDCK) epithelial cells exposed to 95% O2 showed intensive dome formation, a manifestation of cell differentiation and transepithelial fluid transport, whereas cells exposed to 40% O2 or to normoxia did not. Hyperoxia-induced dome formation (HIDF) was preceded and accompanied by a significant rise in intracellular pH (pHi) on days 2 (7.53 vs. 7.42) and 3 (7.62 vs. 7.45), as compared with controls. Inhibition of the Na(+)-H+ exchanger by 0.1 or 1.0 mM amiloride caused 29 or 69% reduction of HIDF and completely abolished hyperoxia-induced alkalinization of the cells. HIDF was altered by modification of extracellular pH (pHo); there was a decrease by 84% with pHo 6.8, while pHo 7.8 led to earlier and more intensive dome formation (day 2, +472%; day 3, +27%). We also found that adenosine 3',5'-cyclic monophosphate (cAMP) was increased in hyperoxic cells, a change that was independent from the rise of pHi. We conclude that high-level hyperoxia induces dome formation in MDCK epithelial monolayers by a process involving activation of the Na(+)-H+ exchanger, together with increased intracellular cAMP.
Language
  • English
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closed
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https://sonar.ch/global/documents/1472
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