Inhibition of effects of flow on potassium permeability in single perfused frog mesenteric capillaries

Authors

  • M. Kajimura,

    1. Section of Cellular & Integrative Biology, Division of Biomedical Sciences, Imperial College School of Medicine, Biomedical Sciences Building, South Kensington, London SW7 2AZ, UK
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  • C. C. Michel

    1. Section of Cellular & Integrative Biology, Division of Biomedical Sciences, Imperial College School of Medicine, Biomedical Sciences Building, South Kensington, London SW7 2AZ, UK
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Corresponding author C. C. Michel: Section of Cellular & Integrative Biology, Division of Biomedical Sciences, Imperial College School of Medicine, Biomedical Sciences Building, South Kensington, London SW7 2AZ, UK. Email: c.c.michel@ic.ac.uk

Abstract

  • 1We have investigated the effects of various potential inhibitors on flow-dependent K+ permeability (PK) of single perfused mesenteric microvessels in pithed frogs.
  • 2Neither superfusion with a nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (10 or 100 μmol l−1), nor the addition of indomethacin (30 μmol l−1) to both perfusate and superfusate reduced the positive correlation between PK and flow velocity (U).
  • 3In the presence of agents known to raise intracellular levels of adenosine 3′,5′-cyclic monophosphate (noradrenaline, 8-bromo-cAMP and a combination of forskolin and rolipram) the slope of the relation between PK and U was no longer significant, so that PK was no longer flow dependent.
  • 4These results confirm that the flow dependence of PK is a biological process and not an artefact of measurement and suggest a role for intracellular cAMP rather than nitric oxide or prostacyclin in the flow-dependent modulation of PK in frog mesenteric microvessels.

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