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

Publisher Website
Google Scholar
Abstract
1. We have investigated the effects of various potential inhibitors on flow-dependent K+ permeability (PK) of single perfused mesenteric microvessels in pithed frogs. 2. Neither superfusion with a nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (10 or 100 micromol l-1), nor the addition of indomethacin (30 micromol l-1) to both perfusate and superfusate reduced the positive correlation between PK and flow velocity (U). 3. In 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. 4. These 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.