Neuropeptide Y receptor antagonists in obesity

A novel range based QSAR study of human neuropeptide Y (NPY) Y5 receptor inhibitors

A conventional QSAR study has been carried out using thermodynamic and other descriptors, on a set of arylsulfonamidomethylcyclohexyl derivatives as antagonists of potential obesity drug target human neuropeptide Y Y5 receptor. In addition, a novel range based method was applied to obtain a QSAR model so that the information contained in the compounds for which an approximate value instead of exact value of inhibitory activity was available could be included in the model. Analysis of models suggests that range based model is better in screening biologically active compounds from chemical library. The conventional model is able to predict activity accurately only for active compounds whereas the range based method is better in discriminating active and inactive compounds.

Melanin-concentrating hormone (MCH) reverts the behavioral effects induced by inescapable stress

The aim of this work was to investigate if MCH modifies the feeding and freezing responses in rats exposed to stressful stimuli. We used a basic version of contextual fear, where one group of rats were placed in a novel environment and two different groups were exposed to footshock paradigms, one of them escapable and the other one inescapable. At the end of each treatment, freezing and feeding were measured. Only the animals exposed to inescapable footshock paradigm showed significant increase in the food intake and freezing behavior in comparison to the control animals. The MCH administration (intra-hippocampal or intra-amygdaline) reverted these effects elicited by inescapable footshock. Results presented in this paper lead us to the assumption that the anxiolytic effect of the peptide is responsible for the reversion of the IS effects.

Quantitative structure activity relationship of benzoxazinone derivatives as neuropeptide Y Y5 receptor antagonists

Quantitative structure activity relationship (QSAR) has been established for 30 benzoxazinone derivatives acting as neuropeptide Y Y5 receptor antagonists. The genetic algorithm and multiple linear regression were used to generate the relationship between biological activity and calculated descriptors. Model with good statistical qualities was developed using four descriptors from topological, thermodynamic, spatial and electrotopological class. The validation of the model was done by cross validation, randomization and external test set prediction.

Differential effects of vigabatrin and zonisamide on the neuropeptide Y system in the hippocampus of seizure prone gerbil

Changed neuropeptide Y (NPY) system in the hippocampus has been reported in various experimental epileptic models. However, there have been little data concerning the alteration in the NPY system in the epileptic hippocampus following treatment of anti-epileptic drugs (AEDs). In the present study, therefore, we performed analyses of effects of vigabatrin (VGB) and zonisamide (ZNS) treatment on the NPY system in the hippocampus of the seizure sensitive (SS) gerbils. In SS gerbil, NPY immunoreactivity in the hippocampus was lower than that in seizure resistant gerbil. Following VGB treatment, the number of NPY immunoreactive neurons and NPY mRNA expression were increased in the hilus and the hippocampus proper. In contrast, ZNS treatment markedly elevated only the density of NPY immunoreactive fibers in the dentate gyrus, not in the hippocampus proper, as compared with saline-treated animals. These patterns were observed in the dose-dependent manners. These findings suggest that AEDs treatments may distinctly affect the NPY system in the SS gerbil hippocampus.

Dihydropyridine neuropeptide Y Y1 receptor antagonists 2. bioisosteric urea replacements

Structure-activity studies around the urea linkage in BMS-193885 (4a) identified the cyanoguanidine moiety as an effective urea replacement in a series of dihydropyridine NPY Y(1) receptor antagonists. In comparison to urea 4a (K(i)=3.3 nM), cyanoguanidine 20 (BMS-205749) displayed similar binding potency at the Y(1) receptor (K(i)=5.1 nM) and full functional antagonism (K(b)=2.6 nM) in SK-N-MC cells. Cyanoguanidine 20 also demonstrated improved permeability properties in Caco-2 cells in comparison to urea 4a (43 vs 19 nm/s).

Dihydropyridine neuropeptide Y Y(1) receptor antagonists

Dihydropyridine 5a was found to be an inhibitor of neuropeptide Y(1) binding in a high throughput (125)I-PYY screening assay. Structure-activity studies around certain portions of the dihydropyridine chemotype identified BMS-193885 (6e) as a potent and selective Y(1) receptor antagonist. In a forskolin-stimulated c-AMP production assay using CHO cells expressing the human Y(1) receptor, 6e demonstrated full functional antagonism (K(b)=4.5 nM). Compound 6e inhibited NPY-induced feeding in satiated rats when dosed at 3.0 and 10.0 mg/kg (ip), and also decreased spontaneous overnight food consumption in rats at doses of 10 and 20 mg/kg (ip).

1,3-Disubstituted benzazepines as neuropeptide Y Y1 receptor antagonists

A novel class of potent and selective non-peptide neuropeptide Y (NPY) Y1 receptor antagonists, having benzazepine nuclei, have been designed, synthesized, and evaluated for activity. Through a blind screening we found the compound 1-N-(3-(N'-(tert-butoxycarbonyl)amino)benzyl)-7-methoxy-(3-(3)-methyl ureido)-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (9: IC50 = 1.6 microM). Chemical modifications of 9 gave a potent NPY Y1 antagonist 3-(N-(4-hydroxyphenyl)-N'-methylguanidino)-1-N-(3-(N'-(tert-butoxy carbonyl)amino)benzyl)-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (14c: IC5(0=43 nM), which had no affinity for NPY Y2 and Y5 receptors.

1,3-Disubstituted benzazepines as novel, potent, selective neuropeptide Y Y1 receptor antagonists

A novel series of potent and selective non-peptide neuropeptide Y (NPY) Y1 receptor antagonists, having benzazepine nuclei, have been designed, synthesized, and evaluated for activity. Chemical modification of the R(1) and R(3) substituents in structure 1 (Chart 1) yields several compounds that show high affinity for the Y1 receptor (K(i) values of less than 10 nM). SAR studies revealed that introduction of an isopropylurea group at R(1) and a 3-(benzo-condensed-urea) group, 3-(fluorophenylurea) group, or a 3-(N-(4-hydroxyphenyl)guanidine) group at R(3) in structure 1 afforded potent and subtype-selective NPY Y1 receptor antagonists. 3-(3-(Benzothiazol-6-yl)ureido)-1-N-(3-(N'-(3-isopropylureido++ +))benzyl )-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one (21), which was one of the most potent derivatives, competitively inhibited specific [(125)I]peptide YY (PYY) binding to Y1 receptors in human neuroblastoma SK-N-MC cells (K(i) = 5.1 nM). 21 not only inhibited the Y1 receptor-mediated increase in cytosolic free Ca(2+) concentration in SK-N-MC cells but also antagonized the Y1 receptor-mediated inhibitory effect of peptide YY on gastrin-induced histamine release in rat enterochromaffin-like cells. 21 showed no significant affinity in 17 receptor binding assays including Y2, Y4, and Y5 receptors.