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Haynes AC, Jackson B, Chapman H, Tadayyon M, Johns A, Porter RA, Arch JR. A selective orexin-1 receptor antagonist reduces food consumption in male and female rats. Regul Pept 2000; 96:45-51. [PMID: 11102651 DOI: 10.1016/s0167-0115(00)00199-3] [Citation(s) in RCA: 263] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A variety of evidence implicates the orexins, especially orexin-A, in the regulation of food intake, but it has not been established whether this effect is mediated by the orexin-1 or orexin-2 receptor. In the present study, a selective orexin-1 receptor antagonist, 1-(2-methylbenzoxazol-6-yl)-3-[1,5]naphthyridin-4-yl urea hydrochloride (SB-334867-A), was administered intraperitoneally to rats under various conditions, and food consumption was subsequently measured over 24 h. In male rats, a single dose of SB-334867-A (30 mg/kg, i.p.) given during the light phase reduced both orexin-A-induced food intake (7 nmol, i.c.v.) and feeding stimulated by an overnight fast for 4 h. When given at the start of the dark phase, food consumption was reduced in both male and female rats over 24 h. Daily injections at the start of the dark phase for 3 days reduced natural feeding in male rats over 24 h on days one and three. These findings demonstrate direct inhibition of orexin-A induced food intake with a selective orexin-1 receptor antagonist. Furthermore, the suppression of nocturnal feeding and food intake stimulated by an overnight fast supports other evidence that orexin-A is involved in the regulation of natural feeding and suggests that orexin-1 receptor antagonists could be useful in the treatment of obesity.
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Affiliation(s)
- A C Haynes
- Vascular Biology, SmithKline Beecham Pharmaceuticals, Harlow, CM19 5AW, Essex, UK.
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Tadayyon M, Welters HJ, Haynes AC, Cluderay JE, Hervieu G. Expression of melanin-concentrating hormone receptors in insulin-producing cells: MCH stimulates insulin release in RINm5F and CRI-G1 cell-lines. Biochem Biophys Res Commun 2000; 275:709-12. [PMID: 10964727 DOI: 10.1006/bbrc.2000.3357] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Melanin-concentrating hormone (MCH) is a hypothalamic orexigenic peptide. Recently, an orphan G-protein-coupled receptor (SLC-1) was identified that binds MCH with high affinity. Here, we demonstrate the mRNA expression of this receptor in insulin-producing cells including CRI-G1 and RINm5F cells, and in rat islets of Langerhans. Immunofluorescence studies in CRI-G1 and RINm5F cell-lines demonstrated cell-surface expression of the receptor. Rat MCH significantly stimulated insulin secretion in both cell-lines. The potency and the efficacy of MCH were significantly increased in the simultaneous presence of forskolin, suggesting that MCH may amplify the insulinotropic effect of cyclic AMP elevating stimuli. Salmon MCH, which differs from rat/human MCH by six amino acids, was less efficacious than rat/human MCH in stimulating insulin release. The data provide evidence for the expression of MCH receptors in insulin producing cells. The insulinotropic effect of MCH may contribute to the regulation of metabolism and energy balance by this peptide.
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Affiliation(s)
- M Tadayyon
- Department of Vascular Biology, SmithKline Beecham Pharmaceuticals, Harlow, CM19 5AD, United Kingdom.
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Haynes AC, Jackson B, Overend P, Buckingham RE, Wilson S, Tadayyon M, Arch JR. Effects of single and chronic intracerebroventricular administration of the orexins on feeding in the rat. Peptides 1999; 20:1099-105. [PMID: 10499428 DOI: 10.1016/s0196-9781(99)00105-9] [Citation(s) in RCA: 247] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two novel hypothalamic neuropeptides, orexin-A and -B, are suggested to regulate feeding. A single intracerebroventricular injection of orexin-A (23.4 nmol), administered 3 h into the light phase, increased feeding in satiated rats and prolonged feeding in fasted rats; it also increased feeding when given 6 h into, but not at the start of, the dark phase. An 8-day intracerebroventricular infusion with orexin-A (18 nmol/day) increased daytime feeding on days 2 and 8, but nocturnal feeding was reduced and there was no change in 24 h intake. Orexin-B had no effects. These results demonstrate a circadian variation in feeding responses to orexin-A.
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Affiliation(s)
- A C Haynes
- Vascular Biology, SmithKline Beecham Pharmaceuticals, Harlow, Essex, UK.
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Haynes AC, Arch JR, Wilson S, McClue S, Buckingham RE. Characterisation of the neuropeptide Y receptor that mediates feeding in the rat: a role for the Y5 receptor? Regul Pept 1998; 75-76:355-61. [PMID: 9802429 DOI: 10.1016/s0167-0115(98)00088-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Food intake was measured in freely fed rats following intracerebroventricular administration of neuropeptide Y (NPY) and several of its analogues and antagonists to investigate the hypothesis that the NPY Y5 receptor mediates feeding. Rat NPY (rNPY), rNPY(2-36) and rNPY(3-36) produced similar feeding responses over the dose range 0.7-7.0 nmol. Rat peptide YY (rPYY) was more potent and at least as efficacious as rNPY. [Leu31 Pro34]-rNPY (agonist potency: Y1 > Y5 > Y4 = y6) and human pancreatic polypeptide (hPP) produced flatter dose-response curves, suggesting partial agonism at the receptor(s). rNPY(13-36) (agonist potency: Y2 > Y5) had little activity and rPP was inactive. [D-Trp32]-NPY was a weak orexigenic agent given alone and, consistent with partial agonism, it markedly antagonised the response to porcine NPY (pNPY). Similarly, the receptor antagonist (Y1 > Y4) 1229U91 stimulated feeding slightly, and markedly inhibited rNPY-induced feeding. In contrast to a previous report, BIBP 3226 (70 nmol), another Y1 receptor antagonist, failed to inhibit the response to rNPY. Our data in vivo are inconsistent with findings that hPP, [Leu31 Pro34]-rNPY and [D-Trp32]-rNPY are full agonists at the rat cloned Y5 receptor. Thus, whilst the Y5 receptor may be involved, its participation as the sole receptor mediating the orexigenic action of NPY in the rat remains unproven.
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Affiliation(s)
- A C Haynes
- Department of Vascular Biology, SmithKline Beecham Pharmaceuticals, Harlow, Essex, UK.
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Sakurai T, Amemiya A, Ishii M, Matsuzaki I, Chemelli RM, Tanaka H, Williams SC, Richarson JA, Kozlowski GP, Wilson S, Arch JR, Buckingham RE, Haynes AC, Carr SA, Annan RS, McNulty DE, Liu WS, Terrett JA, Elshourbagy NA, Bergsma DJ, Yanagisawa M. Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior. Cell 1998; 92:1 page following 696. [PMID: 9527442 DOI: 10.1016/s0092-8674(02)09256-5] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Sakurai T, Amemiya A, Ishii M, Matsuzaki I, Chemelli RM, Tanaka H, Williams SC, Richardson JA, Kozlowski GP, Wilson S, Arch JR, Buckingham RE, Haynes AC, Carr SA, Annan RS, McNulty DE, Liu WS, Terrett JA, Elshourbagy NA, Bergsma DJ, Yanagisawa M. Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior. Cell 1998; 92:573-85. [PMID: 9491897 DOI: 10.1016/s0092-8674(00)80949-6] [Citation(s) in RCA: 3834] [Impact Index Per Article: 147.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The hypothalamus plays a central role in the integrated control of feeding and energy homeostasis. We have identified two novel neuropeptides, both derived from the same precursor by proteolytic processing, that bind and activate two closely related (previously) orphan G protein-coupled receptors. These peptides, termed orexin-A and -B, have no significant structural similarities to known families of regulatory peptides. prepro-orexin mRNA and immunoreactive orexin-A are localized in neurons within and around the lateral and posterior hypothalamus in the adult rat brain. When administered centrally to rats, these peptides stimulate food consumption. prepro-orexin mRNA level is up-regulated upon fasting, suggesting a physiological role for the peptides as mediators in the central feedback mechanism that regulates feeding behavior.
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Affiliation(s)
- T Sakurai
- Howard Hughes Medical Institute, Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, 75235-9050, USA
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Turner NC, Morgan PJ, Haynes AC, Vidgeon-Hart M, Toseland N, Clapham JC. Elevated renal endothelin-I clearance and mRNA levels associated with albuminuria and nephropathy in non-insulin-dependent diabetes mellitus: studies in obese fa/fa Zucker rats. Clin Sci (Lond) 1997; 93:565-71. [PMID: 9497794 DOI: 10.1042/cs0930565] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
1. The obese fa/fa Zucker rat is a genetic model of obesity and insulin resistance which develops a number of metabolic and endocrine features of non-insulin-dependent diabetes, including hypertension, proteinuria and glomerular sclerosis. 2. We have investigated the urinary excretion of the metabolites of thromboxane (thromboxane B2) and prostacyclin (6-keto prostaglandin F1 alpha), and of endothelin and cyclic GMP as markers for changes in the balance of renal haemodynamic factors in the obese Zucker rat. 3. Obese fa/fa Zucker rats were hypertensive compared with their lean counterparts (161 +/- 3 and 138 +/- 3 mmHg respectively, P < 0.01); obese animals were also markedly proteinuric (16.7 +/- 6.7 versus 1.1 +/- 0.1 mg/ml) and albuminuric (8.3 +/- 2.9 versus 0.4 +/- 0.25 mg/ml) and excreted less creatinine than lean animals (all P < 0.01). Urinary excretion of endothelin was greater in obese rats (123 +/- 24 versus 62 +/- 10 pg/15 h, P < 0.05) as was the level of pre-proendothelin mRNA, but excretion of cyclic GMP was depressed (12.5 +/- 1.6 versus 27.2 +/- 3.1 nmol/ 15 h, P < 0.01). Histological examination of kidneys from obese animals showed evidence of focal glomerulosclerosis and cortical tubular damage. 4. These results show that increased urinary endothelin is associated with proteinuria and early stage nephropathy in this animal model of non-insulin-dependent diabetes mellitus. This finding, coupled with a decreased excretion of cyclic GMP, suggests that these increased renal vasoconstrictor/vasodilator forces might contribute to the renal functional changes in non-insulin-dependent diabetes mellitus.
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Affiliation(s)
- N C Turner
- Department of Vascular Biology, SmithKline Beecham Pharmaceuticals, Welwyn, Hertfordshire, U.K
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Haynes AC, al-Barazanji KA, Buckingham RE, Arch JR, Gott AL, McClue SJ, Wilson S. Functional characterisation of the neuropeptide Y receptor mediating feeding in the rat. Biochem Soc Trans 1996; 24:286S. [PMID: 8736944 DOI: 10.1042/bst024286s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- A C Haynes
- SmithKline Beecham Pharmaceuticals, Welwyn, Herts, U.K
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Morris RJ, Haynes AC, Fischer SM, Slaga TJ. Concomitant proliferation and formation of a stratified epithelial sheet by explant outgrowth of epidermal keratinocytes from adult mice. In Vitro Cell Dev Biol 1991; 27A:886-95. [PMID: 1748629 DOI: 10.1007/bf02630992] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A chemically defined medium containing 1.2 mM Ca2+ has been developed for the culture of primary epidermal keratinocytes from untreated adult mice such that proliferation is accompanied by the formation of desmosomes and stratification. Cultured cutaneous explants of 1 mm2 from the backs of untreated, control, and carcinogen-exposed mice all demonstrated epithelial outgrowth within 1 wk, and by 5 wk approached confluence with characteristics of terminal differentiation such as desmosomes and stratification. Addition of 12-O-tetradecanoylphorbol-13-acetate (TPA) to the medium in concentrations of 0.001, 0.01, and 0.1 micrograms/ml resulted in a delay of approximately 1 wk in the outgrowth of the explants compared with the acetone controls and in a 30% decrease in the diameter of the epithelial outgrowth at 3 wk. The inhibition in outgrowth was overcome at higher concentrations (0.5, 1.0, and 10 micrograms/ml TPA). No obvious differences in morphology or in the rate of epidermal outgrowth within a 5-wk interval among explants from normal untreated epidermis, epidermis from mice treated with acetone, or epidermis from mice treated with an initiating application of 7,12-dimethylbenz[a]anthracene were observed. The defined composition of this medium and its ability to support reproducibly and conveniently both proliferation and differentiation of normal as well as treated primary adult murine epidermal cells suggest that it should be useful for a number of studies not previously possible that are relevant to the biology of the skin, to toxicology, and to carcinogenesis in the murine model system.
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Affiliation(s)
- R J Morris
- University of Texas M. D. Anderson Cancer Center, Department of Carcinogenesis, Smithville 78957
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