Thromboxane A2 inhibition: therapeutic potential in bronchial asthma.

Bronchial asthma is a disease defined by reversible airway obstruction, bronchial hyperresponsiveness and inflammation. In addition to histamine and acetylcholine, recent studies have emphasized the role of arachidonic acid metabolites (leukotrienes, prostaglandins and thromboxane A(2)) in the pathogenesis of asthma. Among these mediators, thromboxane A(2) (TXA(2)) has attracted attention as an important mediator in the pathophysiology of asthma because of its potent bronchoconstrictive activity.

Pharmacological evaluation of the novel thromboxane modulator BM-567 (II/II). Effects of BM-567 on osteogenic sarcoma-cell-induced platelet aggregation.

Evidence exists that a large number of tumor cells such as osteosarcoma cells stimulate platelet aggregation, which can be an early step in the metastatic processes of these tumors. Thromboxane A(2) (TXA(2)) is released during platelet aggregation, and it has been suggested that this release may be pathogenic for tumor metastasis for several reasons:Some tumors release large amounts of TXA(2) compared to normal tissue.TXA(2) potentiates tumor growth in culture and increases metastasis in animals.

New pyridobenzodiazepine derivatives: modifications of the basic side chain differentially modulate binding to dopamine (D(4.2), D(2L)) and serotonin (5-HT(2A)) receptors.

A series of new pyridobenzodiazepines with variation of the basic side chain were synthesized and evaluated for their binding to D(4.2), D(2L), and 5-HT(2A) receptors in comparison with clozapine, haloperidol, and two parent compounds previously described, 8-chloro-6-(4-methyl-1-piperazinyl)-11H-pyrido[2,3-b][1,4]benzodiazepine (8) and 8-methyl-6-(4-methyl-1-piperazinyl)-11H-pyrido[2,3-b][1,4]benzodiazepine (9). In the piperazine series, replacing the N-methyl group by a N-phenyl moiety (15-17, 30-32) provided a dramatic decrease of affinity for all receptors (K(i) > 1000 nM).

New trends in dual 5-LOX/COX inhibition.

Dual inhibitors are drugs able to block both the COX and the 5-LOX metabolic pathways. The interest of developing such compounds is supported by a large number of pharmacological studies. Compared to COX or LOX pathways single inhibitors, dual inhibitors present at least two major advantages.

Synthesis and biological evaluation of aroylguanidines related to amiloride as inhibitors of the human platelet Na(+)/H(+) exchanger.

Pyridine and benzene bioisosteres of amiloride were synthesized and evaluated for their inhibitory potency against the sodium-hydrogen exchanger (NHE) involved in intracellular pH regulation. The inhibition of NHE was determined by using the platelet swelling assay (PSA) in which the swelling of human platelets was induced by their incubation in an acid buffer (pH 6.7).

Minimal effects of JL 13, a pyridobenzoxazepine derivative with an antipsychotic potential, on circulating prolactin levels in male rats.

Antipsychotic therapy is frequently associated with several side effects such as hyperprolactinemia. The influence of a putative antipsychotic JL 13 on prolactin release was assessed after intraperitoneal injection in gentled male rats in comparison with clozapine and haloperidol. A total of 30 or 150 min after administration, whole blood was collected for preparing serum samples.

The behavioral effects of acute and chronic JL 13, a putative antipsychotic, in Cebus non-human primates.

Rationale: Neuroleptic or antipsychotic drugs are the mainstay of treating acute and chronic psychosis. However, their efficacy is offset by a wide array of side effects, especially extrapyramidal syndromes (EPS). In an attempt to develop novel antipsychotic agents, several animal models have been developed to characterize the profile of new chemical entities.

Novel inhibitors of the sodium-calcium exchanger: benzene ring analogues of N-guanidino substituted amiloride derivatives.

A series of N-guanidino substituted 2,4-diamino-5-carbonylguanidine molecules related to amiloride were synthesised and evaluated for their ability to inhibit the sodium-calcium exchanger in rat insulinoma cells (RINm5F) and human platelets. Specific chemical pathways were used to prepare the benzene derivatives designed as bioisosteric analogues of the pyrazine derivatives of amiloride. Several so-called 'simplified analogues', where some substituents of amiloride were omitted or replaced, were also prepared and included in the biological evaluation.

In vitro effects of aceclofenac and its metabolites on the production by chondrocytes of inflammatory mediators.

Objectives: To investigate the mechanisms of action underlying the anti-inflammatory action of aceclofenac in vivo, we studied in vitro the effect of aceclofenac and its main metabolite, 4'-hydroxyaceclofenac, in comparison with diclofenac, another metabolite, on cyclooxygenases activity as well as interleukin-1beta, -6 and -8, nitric oxide, and prostaglandin E2 production by human osteoarthritic and normal articular chondrocytes.

Methods: Enzymatically isolated human chondrocytes were cultured for 72 h in the absence or presence of interleukin-1beta (IL-1beta) or lipopolysacharride (LPS) and with or without increased amounts (1 to 30 microM) of aceclofenac or metabolites. The production of different cytokines was measured by Enzyme Amplified Sensitivity Immunoassays (EASIA).

Activity of a novel dual thromboxane A(2)receptor antagonist and thromboxane synthase inhibitor (BM-573) on platelet function and isolated smooth muscles.

The pharmacomodulation of sulfonylureas structurally related to torasemide and characterized by a TXA(2)antagonism led to the synthesis of BM-573. This original molecule showed a high affinity (IC(50)1.3 nM) for the TXA(2)receptor of human platelets in comparison with both reference compounds, SQ-29548 (IC(50)21 nM) and sulotroban (IC(50)930 nM).

Pharmacology of the thromboxane receptor antagonist and thromboxane synthase inhibitor BM-531.

BM-531 (N-tert-butyl-N'-[(2-cyclohexylamino-5-nitrobenzene)sulfonyl]urea), a torasemide derivative, is a novel noncarboxylic thromboxane receptor antagonist and thromboxane synthase inhibitor. Indeed, its affinity for human washed platelet TXA2 receptors labeled with [3H]SQ-29548 (IC50 = 0.0078 microM) is higher than sulotroban (IC50 = 0.

Original 2-alkylamino-6-halogenoquinazolin-4(3H)-ones and K(ATP) channel activity.

A series of 6-substituted 2-alkylaminoquinazolin-4(3H)-ones structurally related to 3-alkylamino-4H-pyrido[4,3-e]-1,2,4-thiadiazine 1,1-dioxides were synthesized and tested as putative K(ATP) channel openers on isolated pancreatic endocrine tissue as well as on isolated vascular, intestinal, and uterine smooth muscle. Most of the 6-halogeno-2-alkylaminoquinazolin-4(3H)-ones were found to inhibit insulin release from pancreatic B-cells and to exhibit vasorelaxant properties. In contrast to their pyridothiadiazine dioxide isosteres previously described as more active on the endocrine than on the smooth muscle tissue, quinazolinones cannot be considered as tissue selective compounds.

Evaluation of classical NSAIDs and COX-2 selective inhibitors on purified ovine enzymes and human whole blood.

Cyclooxygenase is the key enzyme in the biosynthesis of prostanoids, biologically active substances involved in several physiological processes and also in pathological conditions such as inflammation. It has been well known for 10 years that this enzyme exists under two forms: a constitutive (COX-1) and an inducible form (COX-2). Both enzymes are sensitive to inhibition by conventional non-steroidal anti-inflammatory drugs (NSAIDs).

Design, synthesis and biological evaluation of a sulfonylcyanoguanidine as thromboxane A2 receptor antagonist and thromboxane synthase inhibitor.

The synthesis and the structure of N-isopropyl-N'-[2-(3'-methylphenylamino)-5-nitrobenzenesulfonyl] urea (14) was drawn from two thromboxane A2 receptor antagonists structurally related to torasemide. Compound 14 showed an IC50 value of 22 nM for the thromboxane A2 (TXA2) receptor of human washed platelets. Compound 14 prevented platelet aggregation induced by arachidonic acid (0.

Structure determination and comparison of BM567, a sulfonylurea, with terbogrel, two compounds with dual action, thromboxane receptor antagonism and thromboxane synthase inhibition.

BM567, a sulfonylurea compound whose crystal structure is here discussed and terbogrel, are both thromboxane receptor antagonists and thromboxane synthase inhibitors. In this paper, their crystallographic and electronic structures are compared and lead to new synthesis prospects among the sulfonylurea series.

Electrooxidation potential as a tool in the early screening for new safer clozapine-like analogues.

The chemical modification of clozapine (1) has permitted the finding of new analogues, e.g., olanzapine (2), quetiapine (3), 5-(4-methylpiperazin-1-yl)-8-chloropyrido[2,3-b][1,5]benzoxazepine fumarate (9), with a clinical or psychopharmacological profile similar to that of clozapine.

Isosterism among analogues of torasemide: conformational, electronic and lipophilic properties.

The structures, electronic (charges, molecular electrostatic potential, molecular orbitals) and lipophilic properties of three isostere analogues of torasemide were determined and the influence of the replacement of the sulfonyl urea group on the conformation and electronic properties of the molecules is discussed. Lipophilicity of the compounds seems to be the most discriminating property along the series and affects their pharmacological activities.

Therapeutic and chemical developments of cholecystokinin receptor ligands.

Cholecystokinin (CCK) is an important 'brain-gut' hormone located both in the gastrointestinal (GI) system and in the CNS. At least two different G-coupled high affinity receptors have been identified: the CCK-A and the CCK-B receptors. Although the complex biological role of CCK is, as yet, not fully understood, its connection with many different physiological processes both at the GI level and at the CNS level is now well established.

Terbogrel, a dual-acting agent for thromboxane receptor antagonism and thromboxane synthase inhibition.

Terbogrel, (E)-6-[4-(3-tert-butyl-2-cyanoguanidino)phenyl]-6-(3-pyridyl)hex-5 -enoic acid, C(23)H(27)N(5)O(2), a mixed thromboxane A(2) receptor antagonist and thromboxane A(2) synthase inhibitor, shows a hairpin-like conformation stabilized by an intramolecular hydrogen bond. A structural feature characteristic of the thromboxane A(2) synthase inhibitor mode is observed: a distance of 8.4257 (19) A between the pyridine N atom and the carboxyl group.

Recent advances in inducible cyclooxygenase (COX-2) inhibition.

Cyclooxygenase is the key enzyme in the biosynthesis of prostanoids, biologically active substances that are involved in several physiological processes but also in pathological conditions such as inflammation. Since ten years now, it is well known that this enzyme exists under two forms: a constitutive (COX-1) and an inducible form (COX-2). Both enzymes are sensitive to inhibition by conventional nonsteroidal anti-inflammatory drugs (NSAIDs).

Effects of a novel non-carboxylic thromboxane A2 receptor antagonist (BM-531) derived from torasemide on platelet function.

In this study we examined the thromboxane A(2)(TXA(2)) receptor antagonist property of BM-531 (N-tert -butyl- N'-[(2-cyclohexylamino-5-nitrobenzene)sulfonyl]urea), a torasemide derivative, on platelet function. The drug affinity for human washed platelet TXA(2)receptors labelled with [(3)H]SQ-29,548 has been determined (IC50: 0.0078 microM) and demonstrated to be higher than sulotroban (IC50: 0.

New trends in thromboxane and prostacyclin modulators.

Thromboxane A2 (TXA2) and prostacyclin (PGI2) are two labile products formed from arachidonic acid by the way of cyclooxygenase. An overproduction of thromboxane A2 has been detected in a series of diseases whereby this prostanoid is assumed to contribute to the underlying pathomechanisms by its potent stimulation of platelet aggregation and smooth muscle contraction. This increased TXA2 biosynthesis is frequently accompanied by a stimulation of prostacyclin formation which is one of the most potent inhibitors of platelet aggregation and smooth muscle contraction.

Effects of JL 3, a putative antidepressant, on rat noradrenergic and serotonergic systems.

Using in vitro electrophysiological procedures, we confirm the inhibitory effect of 10-(4-methylpiperazin-1-yl)pyrido[4,3-b][1, 4]benzothiazepine (JL 3), on dorsal raphe serotonergic (IC(50)=14 microM) and noradrenergic neurons (IC(50)=4.5 microM). The effect on dorsal raphe neurons was reduced by N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinyl- cyclohexanecarboxamide (WAY-100635), suggesting the importance of 5-HT(1A) receptor stimulation.

6-Substituted 2-oxo-2H-1-benzopyran-3-carboxylic acid as a core structure for specific inhibitors of human leukocyte elastase.

Pyridyl esters of 6-substituted 2-oxo-2H-1-benzopyran-3-carboxylic acid were designed as mechanism-based inhibitors of human leukocyte elastase. Compounds of series 4 specifically inhibited this enzyme. Several of the tested compounds (series 2 and 3) acted as powerful time-dependent inhibitors of both human leukocyte elastase and alpha-chymotrypsin; some compounds of these series inhibited thrombin.