Effects of Calcium Depletion on the Junctional Complex between Oxyntic Cells of Gastric Glands

In order to ascertain the role of calcium in maintaining the structure of the junctional complex between oxyntic cells, control gastric mucosae of the frog Rana pipiens were compared with those exposed to 1 to 4 mM ethylenediaminetetraacetic acid (EDTA). Changes in transmucosal potential difference...

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Bibliographic Details
Published in:The Journal of cell biology 1964-07, Vol.22 (1), p.173-188
Main Authors: Sedar, Albert W., Forte, John G.
Format: Article
Language:English
Subjects:
Animals
Anura
Calcium
Cell Membrane
Cell membranes
Cells
Desmosomes
Edetic Acid
Electron microscopy
Fine structure
Gastric Mucosa
Gastric parietal cells
Microscopy, Electron
Old Medline
P branes
Parietal Cells, Gastric
Pharmacology
Tight junctions
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Summary:In order to ascertain the role of calcium in maintaining the structure of the junctional complex between oxyntic cells, control gastric mucosae of the frog Rana pipiens were compared with those exposed to 1 to 4 mM ethylenediaminetetraacetic acid (EDTA). Changes in transmucosal potential difference and mucosal conductance were monitored. In one case a piece of EDTA-treated mucosa was washed and placed in a Ca++-containing solution. Material from all three categories was prepared for electron microscopy (glutaraldehyde and OsO4 fixation with Epon 812 embedding). Electron micrographs showed that after Ca++ depletion the intercellular electron-opaque material of the desmosome disappears and the walls of this component separate. Similar changes were observed in the zonula adhaerens. Consistent changes were difficult to detect in the zonula occludens although in some instances disorganization or separation within the tight junction was seen. These effects on the components of the junctional complex were reversible on readministration of Ca++. The results indicate that Ca++ is important in maintaining the integrity of the junctional complex. A model correlating the fine structural changes with physiological data is presented.
ISSN:0021-9525
1540-8140
DOI:10.1083/jcb.22.1.173