Endothelial action of thienopyridines and thienopyrimidinones in the isolated guinea pig heart.

Antiplatelet thienopyridines (ticlopidine, clopidogrel) and their thienopyrimidinone congeners, induce prostacyclin-dependent thrombolysis in vivo. Here we tested whether thienopyridines (ticlopidine, clopidogrel, and its enantiomer without antiplatelet properties) and structurally related thienopyrimidinones release NO from coronary endothelium in the isolated guinea pig heart, perfused according to Langendorff technique. The involvement of endothelium-derived NO in coronary vasodilation induced by these agents was assessed by effect of L-N(G)-nitro-arginine methyl ester (L-NAME). In addition, effect of thienopyridines or thienopyrimidinones on nitrite accumulation in cultured endothelium was assayed. Tienopyridines (10-100 micromol L(-1)) and thienopyrimidinones (10-30 micromol L(-1)) produced concentration-dependent increase in coronary flow comparable to that induced by acetylcholine (0.1 micromol L(-1)) or bradykinin (3 nmol L(-1)) which was inhibited by L-NAME (by 50-70%) but not by indomethacin. Furthermore, thienopyridines and thienopyrimidinones caused NO release from cultured endothelial cells. In conclusion, both thienopyridines independently from their antiplatelet action and their thienopyrimidinone congeners that are devoid of antiplatelet action stimulate coronary endothelium to release NO. Endothelial action of these compounds merits further investigation.

Synthesis and thrombolytic activity of new thienopyrimidinone derivatives.

It has been observed that ticlopidine and clopidogrel show, apart from their delayed antiplatelet properties, an immediate and transient thrombolytic action related to the ability of these thienopyridines to stimulate the secretory function of vascular endothelium. With the objective to construct new molecules with identical thrombolytic potency but at a higher level, we carried out different structural modifications in the thienopyridine chemical molecule to conclude that the presence of a second N atom in the pyridine cycle (yielding pyrimidine moiety) and the presence of an additional cycle fused to the thienyl ring would lead to enhanced thrombolytic effects. Here we report the six-step synthesis of a series of new benzothienopyrimidinone derivatives characterized by this searched for potent thrombolytic activity. The pharmacological assay used anaesthetised Wistar rats with extracorporal circulation in which arterial blood superfused thrombi adhering to a strip of collagen. Weight of thrombi was continuously monitored. Six compounds of the series were much more potent thrombolytic agents than their thienopyridine references: the effective thrombolytic dose that produced 30% of maximum thrombolysis (ED30) was at a range of 8 to 170 microg kg(-1) as compared with ED30 values of 16000 to 20000 microg kg(-1) for clopidogrel and ticlopidine respectively. Especially with the most active compound, this difference in the threshold thrombolytic dose, giving an intensity of action higher by three orders of magnitude, was accompanied by a lengthening of the response. Apart from that these compounds have shown to be synthetic thrombolytics, they certainly deserve further studying.

Thrombolysis by thienopyridines and their congeners.

We propose that anti-platelet thienopyridines, such as ticlopidine or clopidogrel, are thrombolytic owing to endothelial release of prostacyclin (PGI2) and tissue plasminogen activator (t-PA). In this study we used anaesthetised Wistar rats with extracorporal circulation in which arterial blood superfused thrombi which adhered to a strip of collagen. Weight of thrombi was continuously monitored. When administered intravenously, clopidogrel or its R enantiomer deprived of anti-platelet action, both at doses of 3 mg x kg(-1), produced lost in weight of thrombi by 14.1 +/- 1.3% or 16.0 +/- 1.4% (n = 9), and at doses 10 mg x kg(-1) by 28.3 +/- 2.3% or 30.4 +/- 1.9% (n = 8), respectively. Maximum of thrombolysis occurred 30-45 min following the drug administration. Ticlopidine at a dose of 30 mg x kg(-1) reduced weight of thrombi by 33.7 +/- 1.7% (n = 32). Thrombolytic action of ticlopidine was accompanied by a rise in 6!keto-PGF1alpha blood levels from 0.42 +/- 0.10 to 1.58 +/- 0.29 ng x ml(-1) and t-PA antigen plasma levels from 4.70 +/- 1.00 to 12.90 +/- 1.15 ng x ml(-1) (n = 7). Five out of eleven tested thienopyridine congeners with pyrimidine or pyrimidinone instead of pyridine rings had thrombolytic potencies similar to that of clopidogrel (ED30s at a range of 6.2-11.4 mg x kg(-1)). A substantial increase in thrombolytic potency (ED30s at a range of 0.3-2.1 mg x kg(-1)) was observed for congeners in which thienyl ring was condensed with an additional cyclopentyl, cyclohexyl or cycloheptyl structures or in which thienopyridine complex was replaced for a pyridopyrimidine one. We claim that thienopyridines, independently of their delayed anti-platelet action, do produce immediate thrombolysis in vivo. This new activity emulates capacity of their native, non-metabolised molecules to release prostacyclin and tissue plasminogen activator. We have also shown that structural changes in molecules of thienopyridines may intensify their thrombolytic potency.

Pyrido[2,3-d]pyrimidin-4(3H)-one derivatives and 1,2,3,4-tetrahydro- pyrido[2,3-d]pyrimidine derivatives: synthesis and in vitro study of their activity against platelet aggregation.

Some new derivatives of pyrido[2,3-d]pyrimidin-4(3H)-one A and 1,2,3,4-tetrahydro-pyrido[2,3-d]pyrimidines B were prepared. The study of their in vitro antiaggregating activity showed that the compounds A possessed an inhibitory potency when aggregation was induced with ADP. Their reduction to derivatives of 1,2,3,4-tetrahydro-pyrido[2,3-d]pyrimidine B led to a new series of molecules possessing a greater antiaggregating power. When compared to that of acetylsalicylic acid under the same conditions, this activity was weaker with collagen, the same with arachidonic acid-induced aggregation, but greater when aggregation was induced by ADP. However, they inhibited serotonin release only slightly. Compared to ginkgolide they remained weaker with PAF-induced aggregation.

Thieno[2,3-d]pyrimidin-4(3H)-one derivatives and 1,2-dihydrogenated homologues: synthesis, enhanced in vitro antiaggregant activity for reduced compounds.

Some derivatives of thieno[2,3-d]pyrimidin-4(3 H)-one A and their 1,2-dihydrogenated homologues B were synthesized. The study of their in vitro antiaggregating activity showed that the first compounds exhibited significant inhibiting power when aggregation was induced with ADP. Their reduction to derivatives of 1,2-dihydrothieno[2,3-d]pyrimidin-4(3 H)-one led to a new series of molecules possessing a large antiaggregant activity. When compared to that of acetylsalicylic acid under the same conditions, this activity was the same with collagen or arachidonic acid-induced aggregation, but greater when aggregation was induced by ADP. Serotonin release was also inhibited.

Synthesis and in vitro study of platelet antiaggregant activity of some 4-quinazolinone derivatives.

Some new 4-quinazolinones were prepared. Their antiplatelet activity was evaluated in vitro with respect to aggregation induced by ADP, collagen, arachidonic acid and the platelet serotonin release reaction. Most molecules showed an inhibiting power similar to that of acetylsalicylic acid under the same conditions, and even greater when aggregation was induced by ADP. Reduction of the 4-quinazolinone derivatives to their 1,2,3,4-tetrahydroquinazoline homologues produced an increase in platelet inhibitory action except when ADP is the inductor.

Action of some salicylate derivatives on in vitro platelet aggregation. Inhibitory and inhibition antagonistic effects.

Twenty salicylate derivatives were tested for their antagonistic activity on the inhibitory effect of aspirin on platelet aggregation. The blocking effect was not limited to the salicylate but also characterised some of its substituted compounds. The substituant influence did not seem to be related to electronic or size parameters. This antagonistic activity of these derivatives decreased as concentrations increased, owing to the emergence of their own inhibitory activity: several salicylate derivatives showed dual inhibitory and inhibition antagonistic activity, with both properties present at the same concentration. A mechanism involving dissociated activities on the two enzymatic sites of cyclooxygenase is proposed.

In vitro antiaggregant activity of paracetamol and derivatives.

The in vitro antiaggregating action of paracetamol and ten of its derivatives was studied by observing their action on collagen, adenosine-5 diphosphate (ADP) and arachidonic acid-induced platelet aggregation. It is established that in vitro activity appears not only with paracetamol but also with its positional isomers and its isosteric derivatives; this involves the replacement of oxygen by sulfur and that of the NH group of oxygen. Paracetamol and its derivatives also have an inhibiting effect on the serotonin release and the thromboxane synthesis of collagen-stimulated platelets.

Acetoxy benzene derivatives: in vitro antiaggregant activity.

A dozen acetoxy benzene derivatives (mono- or diacetylated diphenols) were tested for inhibitory activity on platelet aggregation in human platelet rich plasma induced with collagen, ADP and arachidonic acid. All the compounds tested showed an activity, and the results emphasize the antiaggregant properties of diacetylated derivatives which are more potent than aspirin. Unlike aspirin, their action is not prevented by salicylate. However, the large inhibition of serotonin release and thromboxane synthesis localizes their activity in arachidonic acid metabolism.

Relationship between structure and activity of aspirin-related compounds on the inhibition of in vitro platelet aggregation.

Thirteen aspirin-related compounds were tested for inhibitory activity on platelet aggregation in human platelet rich plasma (PRP) induced with ADP, collagen and arachidonic acid. The following structure-activity relationships were found: none of the functional groups used to replace the acetyl group retained the significant antiaggregant activity of aspirin; anti-aggregant activity was enhanced when the carboxylic group was replaced with a hydroxyl or an acetylated hydroxyl group. The activity of these mono and diacetylated pyrocatechol derivatives was unaffected by incubation of PRP with sodium salicylate.

[Tracheobronchial clearance in the hypersecreting asthmatic patient]. / L'épuration trachéo-bronchique chez l'asthmatique hypersécrétant.

Tracheo-bronchial clearance in the hyper-secreting asthmatic patient was studied by observing the elimination over a period of time of a tracer placed on the bronchial wall over time. The authors describe the method used. The analysis of the results enables two purification processes to be distinguished: muco-ciliary activity and cough. The reliability of the method enabled comparison of the results obtained in 7 healthy subjects and 11 hyper-secreting asthmatics. In the healthy subjects, clearance is carried out by the muco-ciliary activity. In the asthmatics, global clearance is normal, but the cough plays an essential role as the muco-ciliary activity is decreased. The question then arises as to whether the decreased muco-ciliary activity in asthmatic patients is due to failure of the bronchial cilia or to the mucus.

Investigation and determination of the antifibrinolytic properties of dipeptides and synthetic compounds.

1) Investigation and evaluation of antifibrinolytic activity of some new compounds has been carried out using two technics based, one on the "standard clots" method and the other one on labelled clots methods. 2) Among the first four members of the linear amino diacids 2-aminopimelic acid possesses a slight antifibrinolytic activity, the others are non active. 3) The two dipeptides having the same chain length as EACA behave differently ; beta alanyl-glycine is practically inactive whilst glycyl-beta alanine possesses a significant inhibiting power. The question is raised as to whether this active dipeptide might play an antifibrinolytic role in the organism. 4) Among the cyclic epsilon-amino acids tested, alpha aminocampholic acid and dl cis (2,2 dimethyl-3-alpha-aminoethyl) cyclobutaneacetic acid possess and activity slightly superior to that of EACA.