Effects of beta-endorphin and met-enkephalin on platelet activity

In the present study, beta -endorphin and met-enkephalin were tested for th eir antiplatelet activity in human platelet-rich plasma (PRP). Blood sample s were obtained from 15 healthy subjects. The results of the study show tha t these two endogenous opioids (200 pg/ml final concentration) reduce plate let aggregation when it is induced by ADP at low dose (0.5 muM). It is like ly due to conformational changes on the platelet membrane that cause a non- specific decreased susceptibility to platelet-aggregating agonists. Am. J. Hematol. 68:1-3, 2001. (C) 2001 Wiley-Liss, Inc.