Facilitation of Cell Coupling Formation between Mouse Macrophages with an Increase in the External Calcium Ion Concentration

Mouse macrophages cultured in vitro for 2 days were coupled to each other electrically. An increase in the concentration of external calcium ion from 0.5 mM to 4.0 mM caused the increased occurrence of coupled cells immediately after replacement. This increase in coupling was inhibited in the presence of 5.3 × 10-6 M Verapamil, 0.1 mM LaCl3, 2.0 mM MnCl2 and 10-11 M colchicine. An increase in the Mg concentration from 0.1 mM to 4.0 mM and in the Ca concentration from 0.5 mM to 10.0 mM did not increase coupling. These results suggest that mouse macrophages are capable of establishing cell coupling with each other in vitro and that calcium ion acts on the cell surface and facilitates the formation of coupling.