The effect of pH on the K+ movements across the human platelet membrane during in vitro incubation in plasma at 37 degrees C.
(1) The K+ concentration in human blood platelets, separated at room temperature from citrated platelet-rich plasma at pH 7.1, was 88 mumol/10(11) platelets. (2) Changing pH in the plasma altered immediately the intracellular K+ concentration in platelets. An equilibrium was reached within 60--90 min and no further change was observed during the next 90 min. The maximum value was found at pH 6.0--6.4. (3) The velocity of passive K+ efflux varied with pH, having a minimum value at pH 6.0--6.4. Increasing the pH to 7.9 accelerated the velocity by a factor of 15. This was found in platelets incubated with ouabain to inhibit the active (Na+, K+)-pump.
D001692:Biological Transport / Q000187:drug effects; D001792:Blood Platelets / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000097:blood*; D012964:Sodium / Q000378:metabolism
D010042:Ouabain; D012964:Sodium; D011188:Potassium