Effect of extracellular calcium on the intracellular calcium level of newborn rat skin basal cells.

The effect of extracellular calcium on the intracellular calcium level of newborn rat skin basal cells was examined. The intracellular calcium level of basal cells was affected by the extracellular calcium concentration on culture of the cells on a collagen-coated filter, but not on a plate. The intracellular calcium ion concentration ([Ca2+]i) of cells on a collagen-coated filter with 0.05 mM external CaCl2 was 15 nM and increased to 20-22 nM on culture with 2.0 mM extracellular CaCl2. From these results we concluded that the culture matrix (e.g. culture plates, or collagen-coated filters) affects the response of the basal cells to changes in the extracellular calcium content. The intracellular calcium level of Swiss 3T3 cells cultured both on plates and collagen-coated filters were affected by the extracellular calcium concentration. Their [Ca2+]i was determined as 49-50 nM in the presence of 0.05 mM external CaCl2, and 54-56 nM in the presence of 2.0 mM CaCl2. These different responses to extracellular Ca2+ may be due to differences in the proliferative profiles of basal cells and fibroblasts.