title: Regulatory volume decrease in COS-7 cells at 22 °C and its influence on the Boyle van't Hoff relation and the determination of the osmotically inactive volume.
abstract: Cryobiological analyses assume that the direction and rate of water movements across cell membranes and equilibrium cell volumes are determined solely by differences in the chemical potentials of intra- and extra-cellular water. A consequence of this assumption is that cells obey the Boyle van't Hoff (BvH) law which states that cell volumes are a linear function of reciprocal osmolality. Extrapolation of the BvH plot to infinite osmolality yields a quantity b, the fractional volume of the cell occupied by solids. In many cells, however, a cell volume excursion above the isotonic volume initiates an energy-requiring response that causes the swollen cells to shrink back to or towards isotonic volume. It is referred to as regulatory volume decrease (RVD). We have observed a strong RVD in COS-7 cells. If not eliminated by keeping exposure times short, this RVD produces a b that is 60% too high (0.48 vs. 0.30). These results indicate the importance of examining cells for volume regulatory mechanisms before performing measurements to determine their osmotic parameters.
authors.affiliation: Fundamental and Applied Cryobiology Group, Department of Biochemistry, Cellular and Molecular Biology, the University of Tennessee, Knoxville, TN 37932, USA. diana.peckys@inm-gmbh.de
authors.forename: Diana
authors.initials: D
authors.lastname: Peckys
authors.forename: Peter
authors.initials: P
authors.lastname: Mazur
mesh_terms: D000818:Animals; D019556:COS Cells; D002468:Cell Physiological Phenomena; D048429:Cell Size; D015925:Cryopreservation; D000882:Haplorhini; D007700:Kinetics; D016018:Least-Squares Analysis; D008954:Models, Biological; D009994:Osmolar Concentration; D009995:Osmosis