AJP - Gastrointestinal and Liver Physiology, Vol 243, Issue 4 297-G303, Copyright © 1982 by American Physiological Society
Localization of ouabain-binding sites in frog gastric mucosa
H. F. Helander and R. P. Durbin
Autoradiography at the light microscopic level was used to localize sites
of [3H]ouabain binding in isolated stimulated frog gastric mucosa. Silver
grains denoting binding were located near basal and lateral surfaces in
both oxyntic and surface epithelial cells. Binding to oxyntic cells
occurred well before inhibition of acid secretion, consistent with the view
that inhibition by this drug is indirect, and subsequent to inactivation of
oxyntic cell Na+-K+-ATPase and the resulting depression of cellular K+. The
presence of Na+-K+-ATPase in surface cells, as shown by binding of labeled
ouabain, suggests a role for that transport enzyme in electrical activity
and secretion of alkali by these cells.
