Abstract
The osmotic permeability coefficient (Pf) was measured with a stopped- flow light-scattering technique. There is an artifactual light- scattering signal produced by the initial mixing that decays with a half-time of approximately 0.2 s. This seriously interferes with the measurement of the osmotically induced change in cell volume, which has a similar half-time. This "injection artifact" is associated with the biconcave shape of the cells. It is negligible for cells that have been made nearly spherical by swelling them in 160 mosmol. The dependence of this artifact on the cell volume may explain the previously observed dependence of Pf on the cell volume. When cells are made echinocytic (and therefore spherically symmetric), this injection artifact becomes negligible at all cell volumes and Pf can be accurately measured. The Pf of echinocytic cells was nearly constant, varying by less than 10% with the direction of flow and the medium osmolarity (160-360 mosmol). The average value of Pf was 2.0 X 10(-2) cm/s (T = 23 degrees C).
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Selected References
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- Blum R. M., Forster R. E. The water permeability of erythrocytes. Biochim Biophys Acta. 1970 Jun 2;203(3):410–423. doi: 10.1016/0005-2736(70)90181-1. [DOI] [PubMed] [Google Scholar]
- Farmer R. E., Macey R. I. Perturbation of red cell volume: rectification of osmotic flow. Biochim Biophys Acta. 1970 Jan 6;196(1):53–65. doi: 10.1016/0005-2736(70)90165-3. [DOI] [PubMed] [Google Scholar]
- Jay A. W. Geometry of the human erythrocyte. I. Effect of albumin on cell geometry. Biophys J. 1975 Mar;15(3):205–222. doi: 10.1016/S0006-3495(75)85812-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Levitt D. G., Mlekoday H. J. Reflection coefficient and permeability of urea and ethylene glycol in the human red cell membrane. J Gen Physiol. 1983 Feb;81(2):239–253. doi: 10.1085/jgp.81.2.239. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Oster G., Zalusky R. Shape transformation of erythrocytes determined by light scattering changes associated with relaxation of particle orientation. Biophys J. 1974 Feb;14(2):124–129. doi: 10.1016/S0006-3495(74)70004-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rich G. T., Sha'afi I., Romualdez A., Solomon A. K. Effect of osmolality on the hydraulic permeability coefficient of red cells. J Gen Physiol. 1968 Dec;52(6):941–954. doi: 10.1085/jgp.52.6.941. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Terwilliger T. C., Solomon A. K. Osmotic water permeability of human red cells. J Gen Physiol. 1981 May;77(5):549–570. doi: 10.1085/jgp.77.5.549. [DOI] [PMC free article] [PubMed] [Google Scholar]