Cation and anion transport pathways in volume regulatory response of human lymphocytes to hyposmotic media
Sarkadi, B.; Cheung, R.; Mack, E.; Grinstein, S.; Gelfand, E.W.; Rothstein, A.
American Journal of Physiology 248(5 Pt 1): C480-C487
1985
ISSN/ISBN: 0002-9513 PMID: 2581453 Document Number: 264477
The regulatory volume decrease of osmotically swollen human peripheral blood lymphocytes was inhibited by agents acting on volume-activated K+- or Cl--transport pathways. Quinine, cetiedil, and 3,3'-dipropylthiadicarbocyanine were found to block the volume-induced K+ transport by interaction with sites on the outside face of the membrane, perhaps by competition with external K+. Drugs known to influence calmodulin action inhibit both volume-induced K+ and Cl- transport to varying degrees. Those inhibitors, particularly of K+ transport, were correlated with their calmodulin antagonist activity. Penetrating SH reagents (in contrast to nonpenetrating ones) are potent inhibitors of both volume-induced K+ and Cl- movements, indicating the presence of functionally important SH groups located within the membrane or at the cytoplasmic face. A number of agents, such as dipyridamole and oligomycin C, are specific inhibitors of the volume-activated anion pathway. The inhibition characteristics of the volume-activated K+ pathway of lymphocytes resemble those of the Ca2+-activated K+ channel of red cells. The volume-induced anion permeability differs from the primary anion-transport pathway of red cells.