Intercellular Ca2+ signaling in alveolar epithelial cells through gap junctions and by
extracellular ATP.
Isakson, Brant E., W. Howard Evans, and Scott Boitano.
1Department of Zoology and Physiology, University of Wyoming, Laramie,
Wyoming 82071«hyphen»3166; and 2Department of Medical Biochemistry, University
of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, Wales
APStracts 7:0250L, 2000.
Inter- and extracellular-mediated changes in intracellular Ca2+ concentration ([Ca2+]i)
can ensure coordinated tissue function in the lung. Cultured rat alveolar epithelial cells
(AECs) have been shown to respond to secretagogues with increases in [Ca2+]i and have
been shown to be gap junctionally coupled. However, communication of [Ca2+]i changes
in AECs is not well defined. Monolayers of AECs were mechanically perturbed and
monitored for [Ca2+]i changes. Perturbation of AECs was administered by a glass probe
to either mechanically stimulate or mechanically wound individual cells. Both
approaches induced a change in [Ca2+]i in the stimulated cell that was propagated to
neighboring cells (Ca2+ waves). A connexin mimetic peptide shown to uncouple gap
junctions eliminated Ca2+ waves in mechanically stimulated cells but had no effect on
mechanically wounded cells. In contrast, apyrase, an enzyme that effectively removes
ATP from the extracellular milieu, had no effect on mechanically stimulated cells but
severely restricted mechanically wounded Ca2+ wave propagation. We conclude that
AECs have the ability to communicate coordinated Ca2+ changes using both gap
junctions and extracellular ATP.
Received 17 May 2000; accepted in final form 25 July 2000
APS Manuscript Number L159-0.
Article publication pending Am J Physiol Lung Cell Mol Physiol
ISSN 1080-4757 Copyright 2000 The American Physiological Society.
Published in APStracts on 7 November 2000