Collagen platelet aggregation

Each platelet aggregation was induced hy 1 y mole of ADP and 0.02 mg of collagen. Platelet aggregation curves were analyzed for index of optical density at 5 minutes after the addition of an inducer of platelet aggregation ( O.D. min, ) The changes in platelet aggregation were also calculated according to the previously shown formula. 

Platelet aggregation inhibition - in vitro (rabbit, aorta) at 300.0 pM, induced by arachidonic acid and collagen. Platelet aggregation inhibition - in vitro (rabbit, aorta) induced by ADP, arachidonic acid, collagen, and PAF... 

Itazigrel (137) is an antithrombotic compound because of its inhibition of platelet aggregation induced by collagen. It is synthe.sizcd froin l-bromo-l-(4-methoxy)benzoyl-4-methoxytol-uene (135) by reaction in the usual way with triflucffothioacetamide (136) to give itazigrel 471. 

In carotid atherosclerosis, plaques may rupture, resulting in collagen exposure, platelet aggregation, and thrombus formation. The clot may cause local occlusion or may dislodge and travel distally, eventually occluding a cerebral vessel. 

MAHMA NONOate spontaneously dissociates in a pH-dependent, first-order process with a half-life of 1 min at 37 °C. In vivo, examination in anesthetised rats showed, that MAHMA NONOate had both platelet inhibitory and vasodepressor effects [50]. Like other NONOates, MAHMA NONOate inhibited collagen-induced and ADP-induced rat platelet aggregation in a concentration-dependent manner [51]. ODQ, a soluble GS inhibitor, caused only small influence on the concentration-response curve to MAHMA NONOate, indicating that cGMP-independent mechanisms play a crucial role. A potential target of MAHMA NONOate induced inhibition was the sarco-endoplasmic reticulum calcium-ATPase of the platelet dense tubular system... 

CysNO is a potent anti-platelet agent Like other nitrosothiols, it increased the intracellular GMP level in platelets in vitro and inhibited collagen-induced platelet aggregation and ADP-induced activation of GP Ilb/IIIa on the platelet surface [45, 47]. However its potency to release NO, stimulate platelet soluble GS and elevate intracellular platelet cGMP was higher than of GSNO [47, 72]. 

SNAC is the most potent inhibitor of collagen-induced platelet aggregation in vitro compared to other S-nitrosothiols (SNAP, GSNO, CysNO and HomocysNo). Although it increased cGMP-levels in platelets [47], SNAC only partially inhibited thrombin-induced P-selectin expression on a platelet surface [79]. 

Like all S-nitrosothiols, HomocysNO inhibited collagen-induced aggregation and stimulated intracellular cGMP-levels in platelets in vitro [47]. 

As a typical example of a 6-heteroarylsubstituted dihydropyridazinone exhibiting antithrombotic activity motapizone, NAT 05-239 (63) (CAS 90697-57-7) may serve [96], Compound CCI 17810 (64) (CAS 76283-03-9) bearing a substituted phenyl moiety at C-6 of the pyridazine system has been shown to inhibit potently in vitro human platelet aggregation (induced by collagen, ADP, thrombin or arachidonic acid) with EC50 values in the range of 0.5-10/rg/ml [245], ... 

Platelet Inhibition Ginger extract has been found to inhibit platelet aggregation induced by arachidonic acid, epinephrine, ADP, and collagen (Srivastava 1984). The extract s ability to inhibit cyclooxygenase activity and thromboxane levels correlated well with inhibition of platelet aggregation (Srivastava 1984 Mustafa et al. 1993). The type of preparation used also affects platelet inhibition, because roasted and charcoal of ginger were effective, while ether extracts of raw and dried ginger were not (Wu et al. 1993). 

In order to ameliorate the atherosclerotic complications of cardiovascular diseases, various means of inhibiting platelet aggregation have been investigated. Several 1,2,3-thiadiazoles were synthesized by the Hurd and Mori s method as collagen-induced inhibitors of platelet aggregation <85JMC442), the most potent being compound (47). 

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