Inhibition of the thrombin-platelet reactions by DuP 714.
The efficacy and specificity of a novel synthetic thrombin inhibitor, DuP 714, on thrombin-induced elevation of cytoplasmic calcium, fibrinogen binding and aggregation in human platelets were examined. Thrombin (0.5 U/ml) stimulated an increase in [125I]fibrinogen binding in gel-filtered platelets which was blocked by DuP 714 with an IC50 value of 2 nM. Thrombin (1 U/ml)-induced elevation of intracellular [Ca2+]i was also blocked by DuP 714 with an IC50 value of 67 nM. A much higher concentration of thrombin (25 U/ml) was used to stimulate aggregation with heparinized platelet-rich plasma. Under these conditions, micromolar concentrations of DuP 714 were needed to inhibit thrombin. In all of these preparations, DuP 714 at concentrations as high as 10(-5) M had no intrinsic effects and did not affect the responses induced by arachidonate, ADP, collagen, epinephrine, vasopressin and serotonin. These data indicate that DuP 714 is a potent and specific thrombin inhibitor capable of arresting the actions of thrombin on human fibrin formation and platelet aggregation and secretion. It may serve as a potential antithrombotic agent for various forms of thrombotic disorders.
Chiu
A T
AT
Cardiovascular Diseases Research, Du Pont Merck Pharmaceutical Company, Wilmington, DE 19880-0400.
Mousa
S A
SA
Pease
L J
LJ
Roscoe
W A
WA
Bozarth
J M
JM
Reilly
T M
TM
Smith
R D
RD
Timmermans
P B
PB
D000244:Adenosine Diphosphate / Q000494:pharmacology; D016718:Arachidonic Acid / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D001896:Boron Compounds / Q000494:pharmacology*; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005340:Fibrinogen / Q000378:metabolism; D006629:Hirudins / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D009842:Oligopeptides / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D001896:Boron Compounds; D006629:Hirudins; D009842:Oligopeptides; D010980:Platelet Membrane Glycoproteins; C066061:acetylphenylalanyl-prolyl-boroarginine; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; D005340:Fibrinogen; D003094:Collagen; D013917:Thrombin; D004837:Epinephrine