Differences in osmoregulation of resistant and nonresistant fibroblasts in hypotonic media and effect of verapamil on osmoregulation

: The osmoregulation of resistant and nonresistant striped hairyfooted hamster fibroblasts in hypotonic medium was studied. It was found that the fibroblasts of a resistant population completely regulate their volume 1 min after diluting the cell suspension with water. Verapamil, an inhibitor of Pgp channels, caused equal swelling of both fibroblast populations in isotonic medium. It was shown that the water entering the cells together with verapamil increases equally the volume of both cell types and remains bound to both resistant and nonresistant fibroblasts after the termination of cell volume regulation.