Thrombin stimulation of platelet oxygen consumption rate

Abstract

Oxygen consumption of human platelets was measured by O 2 cathode. Platelets were prepared by collecting blood into ACD solution, and isolation and washing in buffer by centrifugation. O 2 consumption was measured by vibrating cathode at 25 C in Hank's solution. The Qo 2 was 14.5 ± 4.8 mμmoles/min 10 9 platelets with added glucose and 21.4 ± 5.0 with added glycerol. Thrombin addition resulted in increase in Qo 2 of elevenfold lasting 3–5 min followed by clumping of the platelets. EDTA blocked the thrombin effect. Similar effects were noted when prothrombin was activated to form thrombin. 5-Hydroxytryptamine was without effect. With EDTA the reaction had two phases, a phase of thrombin effect and a calcium-dependent clumping phase. The observations are compatible with the hypothesis that thrombin alters platelet permeability. platelet clumping; viscous metamorphosis of platelets; platelet respiration measurement by O 2 cathode; thrombin effect on platelet respiration; platelet respiration; platelet intermediary metabolism Submitted on September 20, 1963