Sodium, potassium, two chloride cotransport in corneal endothelium: characterization and possible role in volume regulation and fluid transport.

摘要: PURPOSE. To search for membrane transporter proteins that could contribute to volume regulation and fluid transport by corneal endothelium. As an initial step, the authors have focused on Na + -K -2Cl cotransporters. METHODS. Bovine endothelial cells were cultured confluence. 86 Rubidium was used as a tracer K uptake determinations; values normalized per milligram of cell protein. RESULTS. Three components characterized: ouabain (1 mM) sensitive, bumetanide (0.1 ouabain-bumetanide insensitive. Both ouabain-sensitive bumetanide-sensitive increased in presence 26.2 mM HCO 3 - ; 0.5 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid abolished this increase. The component completely inhibited absence or Cl . This 33% hypertonic solution decreased 38% hypotonic solution. protein kinase C activator phorbol 12-myristate 13-acetate activity cotransporter, whereas forskolin, isobutylmethylxanthine, it. Calyculin A (100 nM), inhibitor phosphatases 1 2a, produced large (97%) activation component. CONCLUSIONS. These results provided first time conclusive evidence cotransporter endothelium its possible involvement volume-regulatory. processes these cells. Given reported here, such significantly electrolyte hence across preparation.