Effects of prasugrel, a novel P2Y(12) inhibitor, in rat models of cerebral and peripheral artery occlusive diseases.

Prasugrel is an orally available thienopyridyl prodrug with more potent in vivo antiplatelet effects compared to clopidogrel. In the present study, we examined the effects of prasugrel in rat models of cerebral and peripheral arterial occlusive diseases. Cerebral arterial thrombosis was induced by photochemical irradiation of the middle cerebral artery.

Discovery of R-142086 as a factor Xa (FXa) inhibitor: syntheses and structure-activity relationships of cinnamyl derivatives.

To develop a novel and effective anticoagulant with potent and selective factor Xa (FXa) inhibitory activity, a new series of cinnamyl derivatives with enhanced lipophilicity and prodrug forms were synthesized and their biological activities were evaluated. As a result, we found that cinnamyl derivative (N-[4-[1-(acetimidoyl)piperidin-4-yloxy]-3-carbamoylphenyl]-N-[(Z)-3-(3-amidinophenyl)-2-fluoro-2-propenyl]sulfamoyl)acetic acid dihydrochloride (26d, R-142086) with a fluorine atom on the double bond exhibited potent anticoagulant activity and no mutagenic potential. Moreover, orally administered R-142086 exhibited potent anti-FXa activity and anticoagulant activity in dogs.

Cinnamyl derivatives: synthesis and factor Xa (FXa) inhibitory activities.

To develop a potent and oral anticoagulant, a series of compounds with cinnamyl moiety was synthesized and their factor Xa (FXa) inhibitory activities were examined. As a result, some cinnamyl derivatives showed potent FXa inhibitory activities in vitro. Among them, compounds with substituent at the 3-position on the central benzene ring represented by (N-{4-[1-(acetimidoyl)piperidin-4-yloxy]-3-chlorophenyl}-N-[(E)-3-(3-amidinophenyl)-2-propenyl]sulfamoyl)acetic acid dihydrochloride (45b) and (N-{4-[1-(acetimidoyl)piperidin-4-yloxy]-3-carbamoylphenyl}-N-[(E)-3-(3-amidinophenyl)-2-propenyl]sulfamoyl)acetic acid dihydrochloride (45j) exhibited potent FXa inhibitory activities with IC(50) values of less than 10 nM in vitro.

Functional role of residue 193 (chymotrypsin numbering) in serine proteases: influence of side chain length and beta-branching on the catalytic activity of blood coagulation factor XIa.

In serine proteases, Gly193 (chymotrypsin numbering) is conserved with rare exception. Mutants of blood coagulation proteases have been reported with Glu, Ala, Arg or Val substitutions for Gly193. To further understand the role of Gly193 in protease activity, we replaced it with Ala or Val in coagulation factor XIa (FXIa).

Repeat oral dosing of prasugrel, a novel P2Y12 receptor inhibitor, results in cumulative and potent antiplatelet and antithrombotic activity in several animal species.

Antiplatelet and antithrombotic activity of multiple oral dosing of prasugrel were evaluated in several animal species. Prasugrel's active metabolite concentration-relatedly inhibited in vitro ADP-induced aggregation of rat, rabbit, dog, monkey and human platelets. Oral administration of prasugrel to dogs (0.

Cinnamylindoline derivatives: synthesis and factor Xa (FXa) inhibitory activities.

A series of cinnamylindoline derivatives were synthesized, and their factor Xa (FXa) inhibitory activities and selectivity over trypsin were evaluated. Among them, some novel derivatives showed potent FXa inhibitory activities and good selectivity over trypsin. Especially, (E)-2-{5-[1-(acetimidoyl)piperidin-4-yloxy]-2-[2-(5-amidino-2-hydroxyphenyl)ethen-1-yl]indolin-1-ylsulfonyl}acetic acid (22f) having 2-hydroxycinnamyl moiety exhibited the most potent FXa inhibitory activity in vitro.

The influence of P2Y12 receptor deficiency on the platelet inhibitory activities of prasugrel in a mouse model: evidence for specific inhibition of P2Y12 receptors by prasugrel.

Prasugrel is a novel orally active thienopyridine with faster, higher and more reliable inhibition of platelet aggregation than clopidogrel reflecting its metabolism in vivo to an active metabolite with selective P2Y(12) antagonistic activity. Several lines of evidence support the contention that prasugrel provides selective P2Y(12) receptor antagonistic activity. To date, however, direct evidence of P2Y(12) specific action by prasugrel in vivo is limited.

Indoline derivatives II: synthesis and factor Xa (FXa) inhibitory activities.

Factor Xa (FXa) is well known to play a pivotal role in blood coagulation, so FXa inhibitor is a promising drug candidate for prophylaxis and treatment of thromboembolic diseases. In the course of our research, we have found that (R)-5-[1-(acetimidoyl)piperidin-4-yloxy]-2-(7-amidinonaphthalen-2-yl)-1-(ethanesulfonyl)indoline ((R)-1) showed potent FXa inhibitory activity in vitro. However, single oral administation (RS)-1 showed high toxicity in mice.

Indoline derivatives I: synthesis and factor Xa (FXa) inhibitory activities.

A series of bisamidine derivatives each having a ring structure in the center of the molecule was synthesized and their Factor Xa (FXa) inhibitory activities were evaluated. Among them, some indoline derivatives showed potent inhibitory activities in vitro. In particular, (R)-18a having an (R)-configuration at the 2-position of the indoline ring exhibited the most potent FXa inhibitory activity in vitro, more potent than DX-9065a.

Stereoselective inhibition of human platelet aggregation by R-138727, the active metabolite of CS-747 (prasugrel, LY640315), a novel P2Y12 receptor inhibitor.

CS-747 (Prasugrel, LY640315) is a thienopyridine antiplatelet prodrug that is metabolized to the thiol-containing active metabolite R-138727,which binds to and irreversibly inhibits the platelet P2Y12ADP receptor. R-138727 is composed of 4 stereo-isomers, (R, S)-, (R, R)-, (S, S)-, and (S, R)-isomers (the first letter for the configuration of a chiral center at the sulfur-bearing position and the second for that at the benzylic position). In the present study, we determined the stereoselectivity of P2Y12 antagonist effects by assessing the antagonism of the [3H]-2-MeS-ADP that binds to human P2Y12 receptors expressed in Chinese hamster ovary cells as an affinity assay, and by the inhibition of ADP-induced aggregation of washed human platelets as a functional assay.

Effects of R-102444 and its active metabolite R-96544, selective 5-HT2A receptor antagonists, on experimental acute and chronic pancreatitis: Additional evidence for possible involvement of 5-HT2A receptors in the development of experimental pancreatitis.

The effects of R-102444 ((2R, 4R)-4-lauroyloxy-2-[2-[2-[2-(3-methoxy)phenyl]ethyl]phenoxy]ethyl-1-methylpyrrolidine hydrochloride) and its active metabolite R-96544 ((2R, 4R)-2-[2-[2-[2-(3-methoxy)phenyl]ethyl]phenoxy]ethyl-4-hydroxy-1-methylpyrrolidine hydrochloride), potent and selective 5-hydroxytryptamine 2A (5-HT2A) receptor antagonists, on development of pancreatitis were investigated in experimental models of acute and chronic pancreatitis. Rat acute pancreatitis was induced by caerulein (20 microg/kg) intraperitoneal injection and by pancreatic duct ligation. In both the models, serum amylase and lipase activities were markedly increased.

Exosite-mediated substrate recognition of factor IX by factor XIa. The factor XIa heavy chain is required for initial recognition of factor IX.

Studies of the mechanisms of blood coagulation zymogen activation demonstrate that exosites (sites on the activating complex distinct from the protease active site) play key roles in macromolecular substrate recognition. We investigated the importance of exosite interactions in recognition of factor IX by the protease factor XIa. Factor XIa cleavage of the tripeptide substrate S2366 was inhibited by the active site inhibitors p-aminobenzamidine (Ki 28 +/- 2 microM) and aprotinin (Ki 1.

Effects of R-102444, an orally active 5-HT2A receptor antagonist, in rat models of peripheral vascular disease.

R-102444 is a prodrug that is metabolized into R-96544, a potent and selective 5-hydroxytryptamine2A (5-HT2A) receptor antagonist. The effects of R-102444 on peripheral vascular disease were examined using two different rat models: one induced by lauric acid and the other by ergotamine plus epinephrine. R-96544 (0.

Structural role of Gly(193) in serine proteases: investigations of a G555E (GLY193 in chymotrypsin) mutant of blood coagulation factor XI.

In serine proteases, Gly(193) is highly conserved with few exceptions. A patient with inherited deficiency of the coagulation serine protease factor XI (FXI) was reported to be homozygous for a Gly(555) --> Glu substitution. Gly(555) in FXI corresponds to Gly(193) in chymotrypsin, which is the numbering system used subsequently.

Pharmacological profiles of R-96544, the active form of a novel 5-HT2A receptor antagonist R-102444.

We examined the pharmacology of (2R,4R)-4-hydroxy-2-[2-[2-[2-(3-methoxy)phenyl]ethyl]phenoxy]ethyl-1-methylpyrrolidine hydrochloride (R-96544), the active form of a novel 5-HT(2A) receptor antagonist, (2R,4R)-4-lauroyloxy-2-[2-[2-[2-(3-methoxy)phenyl]ethyl]phenoxy]ethyl-1-methylpyrrolidine hydrochloride (R-102444). R-96544 produced a concentration-dependent inhibition of platelet aggregation induced by serotonin (5-hydroxytryptamine, 5-HT) alone or in combination with ADP in platelets from humans, monkeys, cats, rabbits, rats and mice. An intravenous administration of R-96544 to rabbits significantly inhibited ex vivo platelet aggregation induced by 5-hydroxytryptamine (5-HT) combined with epinephrine.

Platelet alpha-granule secretion and its modification by SC-57101A, a GPIIb/IIIa antagonist.

Platelet-agonist interaction results in aggregatory and secretory responses. While the activation of glycoprotein (GP) IIb/IIIa plays an essential role in platelet aggregation, its role in granule secretion is not clear. The present study was performed to examine the effect of 3-[[[[1-[4-(aminoiminomethyl) phenyl]-2-oxo-3S-pyrrolidinyl]amino]carbonyl]amino]-propanoate monohydrochloride salt (SC-57101A), a GPIIb/IIIa antagonist, on platelet alpha-granule secretion responses to collagen, ADP, and thrombin receptor activating peptide (TRAP).