Pilar Goya

Antiobesity effects of the novel in vivo neutral cannabinoid receptor antagonist 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-3-hexyl-1H-1,2,4-triazole - LH 21

The present study evaluates the pharmacological profile of the new neutral cannabinoid CB1 receptor antagonist 5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-3-hexyl-1H-1,2,4-triazole -LH-21- on feeding behavior and alcohol self-administration in rats, two behaviors inhibited by cannabinoid CB1 receptor antagonists. Administration of LH-21 (0.03, 0.3 and 3 mg/kg) to food-deprived rats resulted in a dose-dependent inhibition of feeding. Subchronic administration of LH-21 reduced food intake and body weight gain in obese Zucker rats. Acute effects on feeding were not associated with anxiety-like behaviors, or induction of complex motor behaviors such as grooming or scratching sequences, usually observed after central administration of cannabinoid receptor blockers with inverse agonist properties. LH-21 did not markedly reduce alcohol self-administration (30% reduction observed only at a high dose of 10 mg/kg). This pharmacological pattern partially overlaps that of the reference cannabinoid CB1 receptor antagonist N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide, SR141716A, (0.3, 1 and 3 mg/kg) that reduced feeding and alcohol self-administration with similar efficacy. In vitro analysis of blood-brain barrier permeability using a parallel artificial membrane permeation assay demonstrated that LH-21 has lower permeation through membranes than SR141716A. That was confirmed in vivo by studies showing lower potency of peripherally injected LH-21 when compared to SR141716A to antagonize motor depression induced by intracerebroventricular administration of the CB1 agonist CP55,940. The neutral antagonist profile and the lower penetration into the brain of LH-21 favour this class of antagonists with respect to reference inverse agonists for the treatment of obesity because they potentially will display reduced side effects.

Central versus peripheral antagonism of cannabinoid CB1 receptor in obesity: effects of LH-21, a peripherally acting neutral cannabinoid receptor antagonist, in Zucker rats.

The endogenous cannabinoid system plays an important modulatory role in feeding behaviour and metabolism, acting at both central and peripheral levels. Chronic administration of cannabinoid CB1 receptor antagonists has been found to be effective in experimental obesity. However, clinically available cannabinoid receptor antagonists are inverse agonists that can target CB1 receptors located in both central circuits regulating appetite and motivation and in peripheral organs regulating metabolism and energy expenditure. This profile complicates understanding of cannabinoid CB1 receptor blockade as a therapeutic strategy in obesity and metabolic disorders. This review aims to explore the relevance of both inverse agonism and peripheral cannabinoid receptor blockade on the beneficial actions of chronic cannabinoid receptor blockade, by comparing the actions of the reference antagonist/inverse agonist rimonabant and the newly designed drug LH‐21. LH‐21 is a triazol derivative and a neutral cannabinoid receptor antagonist; it has a poor penetration rate into the central nervous system. When given acutely it decreases food intake and enhances the anorectic actions of oleoylethanolamide, a feeding suppressant lipid that acts on peripheral sensory terminals in a similar way as rimonabant. Unlike rimonabant, chronic administration of LH‐21 (3 mg/kg) reduces feeding but does not improve hypertriglyceridaemia or hypercholesterolaemia; nor does it reduce liver fat deposits in Zucker rats. These results suggest that the inverse agonism and/or the antagonism of central cannabinoid CB1 receptors are necessary for the metabolic benefits of cannabinoid CB1 receptor blockade, but not for the appetite reduction.

Heterocycles containing the sulfamide moiety

Publisher Summary This chapter attempts to cover several kinds of heterocycles containing the sulfamide moiety. Earlier reports dealt with cyclic sulfamides, and with the chemistry of thiadiazole and thiadiazine S-oxides. These compounds have also been mentioned in Comprehensive Heterocyclic Chemistry . There has been extensive work on the chemistry and reactions of sulfamide and of alkylsulfamoyl chlorides that include heterocycles of this kind. This chapter offers a more extensive scope, since it covers some aspects of thiadiazines and thiadiazoles, such as tautomerism and aromaticity that had not previously been dealt with. It also includes other heterocycles. This article has been divided on the basis of the nature and size of the heterocyclic ring. The size of the rings range from three- to nine-membered heterocycles, although a ring with 30 members has also been described. A variety of biological activities are reported for different heterocycles containing the sulfamide moiety. For the sake of brevity, they are listed together with their respective structures.

Tautomerism and acidity in 4-quinolone-3-carboxylic acid derivatives

hototropic tautomerkm in 4-quinolone-3-carboxylic acid derivatives has been studied with particular emphasis on the intluence of the ring substituents on the equilibrium. The techniques used include W. 1H-NMR. 13C-NMR (soluttonl and 13C-NMR CP/MAS (solid state) and semiempirical and ab tnltio calculations. The pKa values of some quinolone derivatives have been determined and correlated with data obtained fkom semiempirical methods.

CB1 cannabinoid antagonists: Structure-activity relationships and potential therapeutic applications

During the last decade there has been a growing interest towards the modulation of the cannabinoid CB1 receptor. The identification of CB1 cannabinoid receptor antagonists has been one of the major advances in cannabinoid research. Thus, the development of these ligands has opened new therapeutic applications. Since the discovery of the first cannabinoid receptor antagonist, rimonabant, by Sanofi in 1994, a large number of structural variations within this chemical series of 1,5-diarylpyrazoles have been described. So far, all attempts to identify novel structures for CB1 antagonists have been based on one or more pharmacophoric elements of the rimonabant structure. The advanced clinical trials of rimonabant confirm the therapeutic potential value of CB1 antagonists for the treatment of obesity. In addition, the results of pharmacological and clinical studies reveal other effective pharmacotherapeutic applications. The current review will mainly focus on the structure-activity relationships that have been established for antagonists/inverse agonists that bind to the CB1 cannabinoid receptors and on their therapeutic applications.

New aromatic iminoimidazolidine derivatives as α1-adrenoceptor antagonists: a novel synthetic approach and pharmacological activity

The design, synthesis and alpha1-adrenoceptor antagonism of a series of bis-imidazoline (1a, 2a, 3a and 4a) and bis-guanidine (1b, 2b, 3b and 4b) diphenyl derivatives are reported. All of these compounds fulfill the conditions of the most recent pharmacophore proposed for alpha1-adrenoceptors and found in the literature. Besides, a novel synthetic approach to the preparation of 2-(arylimino)imidazolidine derivatives is described. All the tested compounds, except the bis-guanidinium derivative 3b, inhibit the contractile responses induced by noradrenaline in aortic rings of rat and rabbit in a dose-dependent manner. Our results indicate that, even though some discrepancies are observed in terms of the alpha1 subtype targeted by this new family of compounds, they show an interesting profile as antagonists of alpha1-adrenoceptors and a new prototype, compound 1a, has been found deserving further development.

Anti‐obesity efficacy of LH‐21, a cannabinoid CB1 receptor antagonist with poor brain penetration, in diet‐induced obese rats

BACKGROUND AND PURPOSE Peripheral blockade of cannabinoid CB1 receptors has been proposed as a safe and effective therapy against obesity, putatively devoid of the adverse psychiatric side effects of centrally acting CB1 receptor antagonists. In this study we analysed the effects of LH‐21, a peripherally acting neutral cannabinoid receptor antagonist with poor brain penetration, in an animal model of diet‐induced obesity.

Recent advances in cannabinoid receptor agonists and antagonists

This review is an overview of the recent advances in cannabinoid chemistry with a special emphasis on the patent literature. The term cannabinoid includes analogues of the natural components of cannabis, endocannabinoids and a wide array of chemical structures such as 1,5-diarylpyrazoles, indoles, quinolines and arylsulphonamide derivatives capable of acting as cannabinoid receptor agonists and antagonists. These receptors, discovered in the early nineties, seem to be involved in different biochemical processes and thus represent interesting therapeutic targets for drug research.

Antiobesity designed multiple ligands: Synthesis of pyrazole fatty acid amides and evaluation as hypophagic agents.

Searching for new antiobesity agents, a new series of fatty acid amide derivatives of 1,5-diarylpyrazole have been synthesized as dual peroxisome proliferator activated receptor alpha (PPARalpha)/cannabinoid receptor ligands. The compounds have been evaluated in vivo and in vitro as PPARalpha activators and as cannabinoids in two tests of the mouse tetrad. In vivo, food intake studies have been performed with all the compounds. No significant cannabinoid activity has been found but some compounds behaved as potent PPARalpha activators. Several compounds showed anorexigenic properties reducing food intake in rats.

An AB initio comparative study of the electronic properties of sulfonamides and amides

Abstract A comparative ab initio study of amides and sulfonamides has been carried out using minimal, extended and polarization basis sets. Rotational barriers and tautomerism are discussed comparatively. The two main conclusions of this study are the absence in sulfonamides of a conjugation of the type present in planar amides and the relative insensitivity of the total energy to nitrogen hybridization in sulfonamides in contrast with amides.