Solute-dependent activation of cell motility in strongly hypertonic solutions in Dictyostelium discoideum, human melanoma HTB-140 cells and walker 256 carcinosarcoma cells

Published data concerning the effects of hypertonicity on cell motility have often been controversial. The interpretation of results often rests on the premise that cell responses result from cell dehydration, i.e. osmotic effects. The results of induced hypertonicity on cell movement of Dictyostelium discoideum amoebae and human melanoma HTB-140 cells reported here show that: i) hypertonic solutions of identical osmolarity will either inhibit or stimulate cell movement depending on specific solutes (Na(+) or K(+), sorbitol or saccharose); ii) inhibition of cell motility by hypertonic solutions containing Na(+) ions or carbohydrates can be reversed by the addition of calcium ions; iii) various cell types react differently to the same solutions, and iv) cells can adapt to hypertonic solutions. Various hypertonic solutions are now broadly used in medicine and to study modulation of gene expression. The observations reported suggest the need to examine whether the other responses of cells to hypertonicity can also be based on the solute-dependent cell responses besides cell dehydration due to the osmotic effects.