Volume-activated DIDS-sensitive whole-cell chloride currents in trout red blood cells.
1. The nystatin-perforated whole-cell recording mode of the patch-clamp technique was used to investigate the membrane conductance of trout (Oncorhynchus mykiss) red blood cells in the steady state, 5 min after exposure to hyposmotic medium and 10 min after return to normal isosmotic medium. 2. Whole-cell I-V relations showed outward rectification when red blood cells were bathed in isosmotic (320 mosmol l-1) saline solution and the patch pipette was filled with 117 mM KCl. The membrane conductance was 2.58 +/- 0.59 nS (number of experiments, n = 18) between 0 and 100 mV and 1.32 +/- 0.19 nS (n = 18) between 0 and -100 mV. Removal of Cl- from the extracellular side or incubation with the Cl- channel blocker DIDS caused a reduction in whole-cell membrane conductance by more than 50%, indicating that the membrane current was generated by Cl- ions. The remaining conductance was voltage independent and probably due to non-selective cation conductance. 3. The membrane conductance increased approximately 2-fold after cell swelling induced by exposure to hyposmotic saline solution (215 mosmol l-1). This effect was abolished in Cl(-)-free hyposmotic medium or in the presence of DIDS. 4. The return to isosmotic solution produced a fall in membrane conductance to, or below, control values. 5. We conclude that trout red blood cells possess a significant Cl- conductance in the steady state which is reversibly activated during cell swelling and contributes to volume recovery.
Egée
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CNRS, Unité de Recherche en Physiologie Cellulaire, Université de Bretagne Occidentale, Brest, France.
Harvey
B J
BJ
Thomas
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S
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology*; D000818:Animals; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D004558:Electric Stimulation; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology; D017686:Oncorhynchus mykiss / Q000097:blood*; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D014867:Water / Q000378:metabolism
D018118:Chloride Channels; D014867:Water; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid