Inhibitor effects on the ionic exchanges through the human amniotic epithelial cell membranes.

Direct measurements of cell podocyte/or microvillous membrane ionic exchanges were performed on the membranes of isolated human amniotic epithelial cells. The ionic exchanges were determined from the measures of cellular input conductances. The effects of various inhibitors: ouabain, amiloride, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS), 4'4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), quinidine, barium, manganese were analyzed. This study shows that the ionic exchanges through the epithelial cells are regulated by the presence of Na+,K+,Cl- channels, Na+/H(+)-Cl-/HCO3- antiports, (Na-K)ATPase and Na+/Ca(2+)-Na+/Mg2+ exchangers on the 2 faces of the cells and of a Na(+)-K(+)-2Cl- cotransport on the membrane facing the amniotic cavity only.