Volume regulation by human lymphocytes. Role of calcium

Journal Article · Sat May 01 00:00:00 EDT 1982 · J. Gen. Physiol.; (United States)

DOI:https://doi.org/10.1085/jgp.79.5.849· OSTI ID:6657343

Grinstein, S; Dupre, A; Rothstein, A

Human peripheral blood lymphocytes regulate their volumes in hypotonic solutions. In hypotonic media in which Na+ is the predominant cation, an initial swelling phase is followed by a regulatory volume decrease (RVD) associated with a net loss of cellular K+. In media in which K+ is the predominant cation, the rapid initial swelling is followed by a slower second swelling phase. /sup 86/Rb+ fluxes increased during RVD and returned to normal when the original volume was approximately regained. Effects similar to those induced by hypotonic stress could also be produced by raising the intracellular Ca++ level. In isotonic, Ca++-containing media cells were found to shrink upon addition of the Ca++ ionophore A23187 in K+-free media, but to swell in K+-rich media. Exposure to Ca++ plus A23187 also increased /sup 86/Rb+ fluxes. Quinine (75 microM), an inhibitor of the Ca++-activated K+ pathway in other systems blocked RVD, the associated K+ loss, and the increase in /sup 86/Rb+ efflux. Quinine also inhibited the volume changes and the increased /sup 86/Rb fluxes induced by Ca++ plus ionophore. The calmodulin inhibitors trifluoperazine, pimozide and chlorpromazine blocked RVD as well as Ca++ plus A23187-induced volume changes. Trifluoperazine also prevented the increase in /sup 86/Rb+ fluxes and K+ loss induced by hypotonicity. Chlorpromazine sulfoxide, a relatively ineffective calmodulin antagonist, was considerably less potent as an inhibitor of RVD than chlorpromazine. It is suggested than an elevation in cytoplasmic (Ca++), triggered by cell swelling, increases the plasma membrane permeability to K+, the ensuing increased efflux of K+, associated anions, and osmotically obliged water, leading to cell shrinking (RVD).

• Research Organization: Department of Cell Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
• OSTI ID: 6657343
• Journal Information: J. Gen. Physiol.; (United States), Vol. 79:5
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
CELL MEMBRANES
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LYMPHOCYTES
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ISOTOPE APPLICATIONS
CALCIUM
POTASSIUM
SODIUM
VOLUME
ALKALI METAL ISOTOPES
ALKALI METALS
ALKALINE EARTH METALS
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BLOOD
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BODY FLUIDS
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INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
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METALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
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