stirring of platelet-rich plasma with a number of different platelet-aggregating agents including epinephrine , norepinephrine , arachidonic acid , collagen , adenosine diphosphate , a23187 , and platelet-activating factor failed to release significant amounts of immunoreactive vasopressin , despite the expected aggregation and secretion of platelet factor 4 by these agents .
C0014563
epinephrine
C0028351
norepinephrine