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), Journal Name: J. Gen. Physiol.; (United States) Vol. 80:6; ISSN JGPLA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL ISOTOPES
ALKALI METALS
ANIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BIOLOGICAL MATERIALS
BIOLOGY
BLOOD
BLOOD CELLS
BODY FLUIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
CHEMISTRY
CHLORINE 36
CHLORINE ISOTOPES
CULTURE MEDIA
CYTOLOGY
DAYS LIVING RADIOISOTOPES
ELECTRIC POTENTIAL
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
INTERMEDIATE MASS NUCLEI
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LEUKOCYTES
LIGHT NUCLEI
MATERIALS
MEMBRANE TRANSPORT
MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
MONOCYTES
NUCLEI
ODD-ODD NUCLEI
PERMEABILITY
POTASSIUM
RADIOISOTOPES
RUBIDIUM 86
RUBIDIUM ISOTOPES
TRACER TECHNIQUES
YEARS LIVING RADIOISOTOPES