Thrombin stimulates Na+-H+ exchange across the human platelet plasma membrane.
We have investigated the release of protons from thrombin-stimulated platelets. Addition of thrombin to suspensions of washed platelets resulted in fast liberation of H+. In the presence of 0.1 mM amiloride, a potent inhibitor of the Na+/H+ transport system, the amount of protons liberated was decreased by about 50%, and was further reduced to about 15% by 1 mM amiloride. Similar inhibition of H+ release was observed after Na+ in the incubating medium had been replaced by choline. We conclude that one of the earliest events in thrombin-stimulated platelets consists of the activation of an Na+/H+ countertransport, which leads to an increase in intracellular pH.
D000584:Amiloride / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D001792:Blood Platelets / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D011522:Protons; D012964:Sodium / Q000097:blood*; D013917:Thrombin / Q000494:pharmacology*
D011522:Protons; D000584:Amiloride; D012964:Sodium; D013917:Thrombin