Effects of salts in promoting the adhesion of amphibian gastrula cells.

Presumptive ectodermal and endodermal cells were isolated from the gastrula of the newt Cynops pyrrhogaster, and the effects of salts on embryonic cell adhesion were examined. When the concentrations of NaCl, KCl, MgSO4 and Ca (NO3)2 in the culture medium were increased individually, they all effectively promoted ectodermal cell adhesion. MgSO4 and Ca(NO3)2 promoted endodermal cell adhesion, but NaCl and KCl did not. The culture medium containing increased NaCl (90 mM) nonspecifically promoted ectodermal cell adhesion to the four substrata studied--polystyrene dish, glass, collagen, and fibronectin. The effects of drugs that influence the membrane permeability of Na+ and Ca2+ and the replacement of Na+, Cl-, and Ca2+ with other ions were studied. The results show that the flow of Na+ and Ca2+ into the cytoplasm promotes ectodermal cell adhesion but exerts no influence on endodermal cell adhesion.