Pflügers Archiv

, Volume 432, Issue 2, pp 270–277

The effects of oxygenation upon the Cl-dependent K flux pathway in equine red cells


  • N. A. Honess
    • Department of Environmental and Evolutionary BiologyUniversity of Liverpool
  • J. S. Gibson
    • Department of Veterinary Preclinical SciencesUniversity of Liverpool
  • A. R. Cossins
    • Department of Environmental and Evolutionary BiologyUniversity of Liverpool
Original Article Molecular and cellular physiology

DOI: 10.1007/s004240050133

Cite this article as:
Honess, N.A., Gibson, J.S. & Cossins, A.R. Pflugers Arch. (1996) 432: 270. doi:10.1007/s004240050133


The effects of oxygen tension (PO2) upon the K influx pathways of equine red cells have been studied using 86Rb+ as congener for K. Equilibration of cells in 100% nitrogen led to a low and Cl-independent K flux. Change to an atmosphere of 100% air led to a rapid sixfold increase in K flux. The oxygen-activated flux was entirely Cl dependent and was maintained for up to 3 h. Oxygenation-evoked activation was dependent upon PO2 over the physiological range with little effect up to 70% saturation of haemoglobin with oxygen but significant effects between 70 and 100%. K flux at low PO2 was unaffected by acidification to pH 7 or by hypotonic cell swelling. By contrast, at high PO2 both manipulations caused a substantial increase in Cl-dependent K flux. N-Ethylmaleimide (NEM; 1 mM) caused a progressive activation of KC1 cotransport in cells held under nitrogen. The protein phosphatase inhibitor, calyculin A (100 nM), applied during NEM-evoked activation caused a “clamping” of K influx at that level. This “clamped” activity was unaffected by subsequent oxygenation. We conclude that oxygenation exerts a primary control over cotransport activity and that acidification and cell swelling are secondary modulators. It appears that oxygenation-evoked activation of the Cl-dependent K flux involves a serine/threonine phosphorylation event. Regulating the PO2 of the solution before and during experiments is important in controlling the activity of the KC1 cotransporter and cell volume.

Key words

KC1 cotransportOxygenKinasePhosphataseEquine red cells

Copyright information

© Springer-Verlag 1996