Deborra Mullins

Activation of the NPY Y5 receptor regulates both feeding and energy expenditure

Intracerebroventricular (ICV) administration of neuropeptide Y (NPY) has been shown to decrease energy expenditure, induce hypothermia, and stimulate food intake. Recent evidence has suggested that the Y5 receptor may be a significant mediator of NPY-stimulated feeding. The present study attempts to further characterize the role of NPY Y5-receptor subtypes in feeding and energy expenditure regulation. Satiated Long-Evans rats with temperature transponders implanted in the interscapular brown adipose tissue (BAT) displayed a dose-dependent decrease in BAT temperature and an increase in food intake after ICV infusion of NPY. Similar effects were induced by ICV administration of peptide analogs of NPY that activate the Y5 receptor, but not by analogs that activate Y1, Y2, or Y4 receptors. Furthermore, ICV infusion of the Y5 selective agonistd-[Trp32]-NPY significantly reduced oxygen consumption and energy expenditure of rats as measured by indirect calorimetry. These data suggest that the NPY Y5-receptor subtype not only mediates the feeding response of NPY but also contributes to brown fat temperature and energy expenditure regulation.Intracerebroventricular (ICV) administration of neuropeptide Y (NPY) has been shown to decrease energy expenditure, induce hypothermia, and stimulate food intake. Recent evidence has suggested that the Y5 receptor may be a significant mediator of NPY-stimulated feeding. The present study attempts to further characterize the role of NPY Y5-receptor subtypes in feeding and energy expenditure regulation. Satiated Long-Evans rats with temperature transponders implanted in the interscapular brown adipose tissue (BAT) displayed a dose-dependent decrease in BAT temperature and an increase in food intake after ICV infusion of NPY. Similar effects were induced by ICV administration of peptide analogs of NPY that activate the Y5 receptor, but not by analogs that activate Y1, Y2, or Y4 receptors. Furthermore, ICV infusion of the Y5 selective agonist D-[Trp(32)]-NPY significantly reduced oxygen consumption and energy expenditure of rats as measured by indirect calorimetry. These data suggest that the NPY Y5-receptor subtype not only mediates the feeding response of NPY but also contributes to brown fat temperature and energy expenditure regulation.

[D-Trp34] neuropeptide Y is a potent and selective neuropeptide Y Y5 receptor agonist with dramatic effects on food intake☆

The neuropeptide Y (NPY) Y(5) receptor has been proposed to mediate several physiological effects of NPY, including the potent orexigenic activity of the peptide. However, the lack of selective NPY Y(5) receptor ligands limits the characterization of the physiological roles of this receptor. Screening of several analogs of NPY revealed that [D-Trp(34)]NPY is a potent and selective NPY Y(5) receptor agonist. Unlike the prototype selective NPY Y(5) receptor agonist [D-Trp(32)]NPY, [D-Trp(34)]NPY markedly increases food intake in rats, an effect that is blocked by the selective NPY Y(5) receptor antagonist CGP 71683A. These data demonstrate that [D-Trp(34)]NPY is a useful tool for studies aimed at determining the physiological roles of the NPY Y(5) receptor.

Comparison of the V1b antagonist, SSR149415, and the CRF1 antagonist, CP-154,526, in rodent models of anxiety and depression

Vasopressin and corticotropin releasing factor (CRF) are both critical regulators of an animals stress response and have been linked to anxiety and depression. As such, antagonists of the CRF1 and V1b receptor subtypes are being developed as potential treatments for affective disorders. The two most characterized V1b and CRF1 antagonists are SSR149415 and CP-154,526, respectively, and the present studies were designed to compare these two compounds in acute animal models of affective disorders. We employed five anxiety models: Separation-induced pup vocalizations (guinea pig and rat), elevated plus-maze (EPM), conditioned lick suppression (CLS), and marble burying (mouse); as well as three depression models: forced swim test (FST; mouse and rat) and tail suspension test (TST; mouse). SSR149415 (1-30 mg/kg) was active in the vocalization, EPM and CLS models, but inactive in marble burying. CP-154,526 (1-30 mg/kg) was active in vocalization models, but inactive in EPM, CLS, and marble burying. SSR149415 was inactive in all depression models; CP-154,526 was active in rat FST but inactive in mouse models. This work demonstrates the different profiles of V1b and CRF1 receptor antagonists and supports both approaches in the treatment of affective disorders.

Inhibitors of platelet-derived growth factor

A method of inhibiting the binding of PDGF using compounds of the formula I ##STR1## useful in the treatment of atherosclerosis, cancer, retinal detachment, pulmonary fibrosis, arthritis, psoriasis and glomerulonephritis, and restenosis following angioplasty or vascular surgery is disclosed. Also disclosed are pharmaceutical compositions and novel PDGF inhibitory compounds of the formula ##STR2## or a pharmaceutically acceptable addition salt thereof, useful in the treatment of atherosclerosis, cancer, retinal detachment, pulmonary fibrosis, arthritis, psoriasis and glomerulonephritis, and restenosis following angioplasty or vascular surgery.

Activation of extracellular signal regulated protein kinase by neuropeptide Y and pancreatic polypeptide in CHO cells expressing the NPY Y1, Y2, Y4 and Y5 receptor subtypes

Abstract Neuropeptide Y (NPY), 36-amino acid amidated peptide expressed in central and peripheral neurons, regulates a variety of physiological activities, including food intake, energy expenditure, vasoconstriction, anxiolysis, nociception and ethanol consumption. NPY binds to a family of G-protein coupled receptors whose activation results in inhibition of adenylyl cyclase activity. To more fully characterize the signal transduction pathways utilized by the NPY receptor subtypes, the pathways leading to phosphorylation of the extracellular signal regulated protein kinases 1 and 2 (ERK) have been compared in CHO cells expressing each of the four cloned human NPY receptor subtypes, Y 1 , Y 2 , Y 4 and Y 5 . NPY Y 1 , Y 2 , Y 4 and Y 5 receptor-mediated ERK phosphorylation was blocked by pertussis toxin (PTX) exposure, indicating that all four receptors are coupled to inhibitory G i/o proteins. Exposure to the protein kinase C (PKC) inhibitor GF109203X diminished Y 1 , Y 2 and Y 4 receptor-mediated ERK phosphorylation but completely blocked Y 5 receptor-mediated ERK phosphorylation. Additionally, Y 5 receptor-mediated ERK phosphorylation was inhibited by the phosphatidylinositol 3-kinase inhibitors LY294002 and wortmannin to a greater extent than was Y 1 -mediated ERK phosphorylation. These results demonstrate that in CHO cells, the Y 5 receptor and the Y 1 , Y 2 and Y 4 receptors utilize different pathways to activate ERK.

Pharmacological characterization of the cloned neuropeptide Y y6 receptor

Neuropeptide Y has potent appetite stimulating effects which are mediated by hypothalamic receptors believed to be of the neuropeptide Y Y(1) and/or neuropeptide Y Y(5) subtype. In mice, the neuropeptide Y y(6) receptor is also expressed in the hypothalamus, suggesting that it too may function as a feeding receptor in this species. Several laboratories have studied the pharmacology of the neuropeptide Y y(6) receptor, but their results are not in agreement. Using neuropeptide Y and a variety of peptide analogs and small molecule antagonists, we have determined that the pharmacology of the cloned mouse neuropeptide Y y(6) receptor is distinct from that of the other known neuropeptide Y receptors. The rank order of binding affinity for the mouse neuropeptide Y y(6) receptor is [(Ile, Glu,Pro,Dpr,Tyr,Arg,Leu,Arg,Tyr-NH(2))(2)human peptide YY=human, rat neuropeptide Y=human, rat neuropeptide Y-(2-36)=human, rat [Leu(31), Pro(34)porcine (Cys(2))-neuropeptide Y-(1-4)-8-aminooctanoyl-(D-Cys(27)porcine [D-Trp(32)rat pancreatic polypeptide=human pancreatic polypeptide. A similar rank order of potency is seen for inhibition of forskolin-stimulated cyclic AMP. The neuropeptide Y Y(5) receptor antagonist trans-naphthalene-1-sulfonic acid ¿4-[4-amino-quinazolin-2-ylamino)-methyl]-cyclohexylmethy l¿-amide hydrochloride (CGP 71683A) and the neuropeptide Y Y(1) receptor antagonist ((R)-N(2)-diphenylacetyl)-N-[(4-hydroxyphenyl)methyl]-argininam ide) (BIBP3226) bind weakly to the neuropeptide Y y(6) receptor (K(i)10, 000 nM, respectively). Although the function of the neuropeptide Y y(6) receptor remains to be elucidated, its pharmacology is not consistent with a role in appetite regulation.

Inhibition of PDGF receptor binding and PDGF-stimulated biological activity in vitro and of intimal lesion formation in vivo by 2-bromomethyl-5-chlorobenzene sulfonylphthalimide.

The proliferation of vascular smooth muscle cells (SMCs) is a key event in the development of atherosclerotic lesions and in the restenosis of arteries after angioplasty. Polypeptide growth factors are potent SMC mitogens in vitro and are believed to be involved in SMC proliferation in vivo. Strong data exist linking platelet-derived growth factor (PDGF) activity to human atherosclerosis. However, no low-molecular-weight antagonists of this growth factor have been discovered. We identified a compound, SCH 13929 (2-bromomethyl-5-chlorobenzene sulfonylphthalimide), which inhibits binding of 125I-PDGF BB to cell surface receptors with an IC50 of 0.13 mumol/L. This compound has a lesser effect on the binding of 125I-epidermal growth factor (EGF), 125I-basic fibroblast growth factor (bFGF), or 125I-endothelin to specific cell surface receptors. Exposure of cultured SMCs to SCH 13929 inhibits PDGF BB- and PDGF AA-stimulated DNA synthesis but not EGF- or bFGF-stimulated DNA synthesis. PDGF BB-stimulated SMC division is also inhibited by exposure to SCH 13929. Chemotaxis assays indicate that SCH 13929 inhibits PDGF-stimulated directional migration and suggest that the compound interacts with PDGF rather than with the receptor. Oral administration of SCH 13929 (100 mg/kg per day) to Sprague-Dawley rats or spontaneously hypertensive rats results in significant inhibition of lesion formation in the balloon catheter-deendothelialized carotid artery. These results suggest that SCH 13929 may be a useful tool for understanding the role of PDGF in intimal lesion formation.

Tetrahydroquinoline sulfonamides as vasopressin 1b receptor anatgonists

Vasopressin 1b (V1b) antagonists have been postulated as possible treatments for depression and anxiety. A novel series of potent and selective V1b antagonists has been identified starting from an in-house screen hit. The incorporation of a sulfonamide linker between a tetrahydroisoquinoline core and amino piperidine lead to the identification of a V1b antagonist with similar affinity for human and rat receptors. Further optimization of the right hand portion afforded potent V1b antagonists that possessed moderate to high selectivity over other receptors.

Discovery and SAR of cyclic isothioureas as novel NPY Y1 receptor antagonists

A class of novel 2-aminobenzothiazoles have been identified as NPY Y(1) antagonists. Various N-heterocyclic substituted aminophenethyl-2-aminobenzothiazole analogs were synthesized to explore the SAR. Isothiourea analogs and ligands with high potency (K(i) 30 nM) have been identified.

Neuropeptide Y (NPY) Y1 Receptor Antagonists

Neuropeptide Y(NPY), a 36-residue peptide amide isolated originally from porcine brain, exhibits a wide spectrum of central and peripheral activities mediated by at least six receptor subtypes denoted as Y1, Y2, Y3, Y4, Y5 and Y6 [1]. Investigations to date have implicated NPY in the pathophysiology of a number of diseases including feeding disorders, seizures, anxiety, hypertension and diabetes. To aid in the determination of the receptor subtype(s) mediating these effects of NPY, efforts have been made to develop highly potent and selective ligands for various NPY receptors. One of these compounds, GR231118, exhibited subnanomolar affinity to Y1 receptors [2], and has therefore been widely used in defining the role and distribution of Yl receptors. However, our recent investigations revealed that both GR231118 and its parent compound, BW1911U90, exhibit potent agonist activity at the Y4 receptors [3]. This paper describes the SAR studies with BW1911U90 that have resulted in the development of a series of potent and selective Y1 receptor antagonists.