a ▁An tagon ist ▁Re agent ▁This ▁re agent ▁is ▁used ▁as ▁a ▁quality ▁control ▁in ▁Multi plate ▁plate let ▁function ▁testing . ▁The ▁G PI I b / III a ▁ant agon ist ▁blocks ▁the ▁binding ▁of ▁f ibr in ogen ▁to ▁the ▁G PI I b / III a ▁re cept ors , ▁prevent ing ▁the ▁formation ▁of ▁plate let - f ibr in ogen ▁b onds ▁and ▁resulting ▁in ▁significantly ▁reduced ▁plate let ▁aggreg ation ▁in ▁response ▁to ▁all ▁ag on ists . ▁The ▁ant agon ist ▁re agent ▁is ▁used ▁together ▁with ▁TR AP - test , ▁and ▁allows ▁assess ment ▁of ▁a ▁positive ▁control . ▁ ▁Pro stag land in ▁E 1 ▁Re agent ▁Pro stag land in ▁E 1 ▁( P GE 1 ) ▁is ▁a ▁plate let ▁in hib itor ▁that ▁causes ▁an ▁increase ▁in ▁cy clic ▁ad en os ine ▁mon oph osph ate ▁( c AMP ) ▁in ▁plate lets ▁by ▁stim ulating ▁ad eny ly l ▁cycl ase ▁activity . ▁c AMP ▁is ▁an ▁int rac ell ular ▁signal ing ▁mole c ule , ▁and ▁the ▁increase ▁in ▁c AMP ▁in hib its ▁calci um ▁mobil ization ▁and ▁plate let ▁aggreg ation ▁induced ▁by ▁activation ▁of ▁the ▁AD P ▁re ceptor ▁P 2 Y 1 . ▁Activ ation ▁of ▁the ▁P 2 Y 1 ▁re ceptor ▁initi ates ▁plate let ▁aggreg ation ▁in ▁response ▁to ▁AD P . ▁The ▁P 2 Y 1 ▁re ceptor ▁is ▁required ▁for ▁AD P - indu ced