Volume-induced increase of anion permeability in human lymphocytes
Peripheral blood mononuclear cells (PBM) readjust their volumes after swelling in hypotonic media. This regulatory volume decrease (RVD) is associated with a loss of cellular K+ and is thought to be promoted by an increased permeability to this ion. In contrast, no change in volume was observed when K+ permeability of PBM in isotonic media was increased to comparable or higher levels using valinomycin. Moreover, valinomycin-induced /sup 86/Rb+ loss in K+-free medium was considerably slower than in K+-rich medium. These results suggest that anion conductance limits net salt loss in isotonic media. Direct measurements of relative conductance confirmed that in volume-static cells, anion conductance is lower than that of K+. In volume-regulating cells depolarization occurred presumably as a result of increased anion conductance. Accordingly, the efflux of /sup 36/Cl from PBM was markedly increased by hypotonic stress. Since both membrane potential and intracellular /sup 36/Cl concentration are reduced in hypotonically swollen cells, the increased efflux is probably due to a change in Cl- permeability. Anions and cations seem to move independently through the volume-induced pathways: the initial rate of /sup 86/Rb uptake in swollen cells was not affected by replacement of external Cl- by SO.4; conversely, /sup 36/Cl fluxes were unaffected by substitution of K+ by Na+. The data indicate that anion conductance is rate-determining in salt and water loss from PBM. An increase in anion conductance is suggested to be the critical step of RVD of human PBM.
- Research Organization:
- Department of Cell Biology, Research Institute, The Hospital for Sick Children, Ontario, Canada
- OSTI ID:
- 6096313
- Journal Information:
- J. Gen. Physiol.; (United States), Vol. 80:6
- Country of Publication:
- United States
- Language:
- English
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MEMBRANE TRANSPORT
CELL MEMBRANES
PERMEABILITY
CHLORINE 36
RUBIDIUM 86
BIOCHEMISTRY
CULTURE MEDIA
CYTOLOGY
ELECTRIC POTENTIAL
MONOCYTES
POTASSIUM
TRACER TECHNIQUES
ALKALI METAL ISOTOPES
ALKALI METALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BIOLOGY
BLOOD
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BODY FLUIDS
CELL CONSTITUENTS
CHARGED PARTICLES
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CHLORINE ISOTOPES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
INTERMEDIATE MASS NUCLEI
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ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
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LEUKOCYTES
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MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
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ODD-ODD NUCLEI
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551001* - Physiological Systems- Tracer Techniques