Effects of a Polyoxyethylene Detergent on Platelet Function
Low concentrations of a polyoxyethylene detergent, Brij 58, inhibited the secondary phase of platelet aggregation induced by ADP in human citrated platelet rich plasma but had no effect on primary aggregation.Thrombin-induced aggregation of washed human platelets suspended in Tyrode’s buffer was inhibited after incubation of cells with 4.5 × 10-6M detergent. Development of prothrombin-converting activity and efflux of [14C]-serotonin, 45Ca2+ ions and labile endoperoxides were abolished concomitantly. Aggregation of washed platelets by collagen or sodium arachidonate and the attachment of cells to clean glass surfaces were also inhibited by the same concentration of Brij 58 that inhibited thrombin aggregation. This concentration of Brij 58 did not itself produce any release of a cytoplasmic marker, lactate dehydrogenase, from platelets. Higher concentrations of Brij 58, exceeding 10-4 M, lysed the cells liberating all of their serotonin, Ca2+ and lactate dehydrogenase. These results suggest that low concentrations of Brij 58 stabilize a membrane conformation against the action of platelet stimulatory agents while high concentrations produce membrane destabilization and cell lysis. The presence of albumin (BSA) in the suspending fluid increased by tenfold the concentrations of detergent required to “elicit these effects and this could be attributed to competitive binding of the detergent to albumin, demonstrated with [14C]-acetylated Brij 58.