Membrane stress increases cation permeability in red cells.
The human red cell is known to increase its cation permeability when deformed by mechanical forces. Light-scattering measurements were used to quantitate the cell deformation, as ellipticity under shear. Permeability to sodium and potassium was not proportional to the cell deformation. An ellipticity of 0.75 was required to increase the permeability of the membrane to cations, and flux thereafter increased rapidly as the limits of cell extension were reached. Induction of membrane curvature by chemical agents also did not increase cation permeability. These results indicate that membrane deformation per se does not increase permeability, and that membrane tension is the effector for increased cation permeability. This may be relevant to some cation permeabilities observed by patch clamping.
Department of Biochemistry, Wayne State Medical School, Detroit, Michigan 48201.
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Johnson
D055592:Biophysical Phenomena; D001703:Biophysics; D002412:Cations / Q000378:metabolism; D002463:Cell Membrane Permeability; D048429:Cell Size; D004907:Erythrocyte Deformability / Q000502:physiology; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology; D006801:Humans; D066298:In Vitro Techniques; D017136:Ion Transport; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D013314:Stress, Mechanical
D002412:Cations