title: The effect of carbonic anhydrase inhibition on the velocity of thrombin-stimulated platelet aggregation under physiological conditions.
abstract: We have studied the effect of ethoxzolamide , a specific carbonic anhydrase inhibitor, on the velocity of thrombin-stimulated platelet aggregation. After preincubation of platelet rich plasma with 10(-6) M ethoxzolamide the velocity of platelet aggregation was reduced by about 40%. Between 10(-11) M and 10(-10)M ethoxzolamide was necessary to achieve a half-maximal diminution of the aggregation velocity. An identical maximal reduction of the velocity of aggregation as with ethoxzolamide could be achieved by a nearly complete removal of CO2 from the platelet rich plasma. These results suggest that the intracellular CO2 hydration-dehydration reaction is involved in the activation of human platelets by thrombin. It is possible that the cytosolic carbonic anhydrase of platelets provides a rapid source of the protons that are transferred across the plasma membrane during the activation process.
mesh_terms: D001792:Blood Platelets / Q000201:enzymology*; D002256:Carbonic Anhydrases / Q000097:blood / Q000502:physiology*; D003600:Cytosol / Q000201:enzymology; D005016:Ethoxzolamide / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D010974:Platelet Aggregation / Q000187:drug effects*; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D013917:Thrombin; D002256:Carbonic Anhydrases; D005016:Ethoxzolamide