Pharmacological Characterisation of the Agonist Radioligand Binding Site of 5-HT(2A), 5-HT(2B) and 5-HT(2C) Receptors

Overview

Journal Naunyn Schmiedebergs Arch Pharmacol

Specialty Pharmacology

Date 2004 Aug 24

PMID 15322733

Citations 80

Authors

Antony R Knight

Anil Misra

Kathleen Quirk

Karen Benwell

Dean Revell

Guy Kennett

Mike Bickerdike

Affiliations

Soon will be listed here.

Abstract

In the present study we compared the affinity of various drugs for the high affinity "agonist-preferring" binding site of human recombinant 5-HT(2A), 5-HT(2B) and 5-HT(2C) receptors stably expressed in monoclonal mammalian cell lines. To ensure that the "agonist-preferring" conformation of the receptor was preferentially labelled in competition binding experiments, saturation analysis was conducted using antagonist and agonist radiolabels at each receptor. Antagonist radiolabels ([3H]-ketanserin for 5-HT(2A) receptor and [3H]-mesulergine for 5-HT(2B) and 5-HT(2C) receptor) bound to a larger population of receptors in each preparation than the corresponding agonist radiolabel ([125I]-DOI for 5-HT(2A) receptor binding and [3H]-5-HT for 5-HT(2B) and 5-HT(2C) receptor binding). Competition experiments were subsequently conducted against appropriate concentrations of the agonist radiolabels bound to the "agonist-preferring" subset of receptors in each preparation. These studies confirmed that there are a number of highly selective antagonists available to investigate 5-HT2 receptor subtype function (for example, MDL 100907, RS-127445 and RS-102221 for 5-HT(2A), 5-HT(2B) and 5-HT(2C) receptors respectively). There remains, however, a lack of highly selective agonists. (-)DOI is potent and moderately selective for 5-HT(2A) receptors, BW723C86 has poor selectivity for human 5-HT(2B) receptors, while Org 37684 and VER-3323 display some selectivity for the 5-HT(2C) receptor. We report for the first time in a single study, the selectivity of numerous serotonergic drugs for 5-HT2 receptors from the same species, in mammalian cell lines and using, exclusively, agonist radiolabels. The results indicate the importance of defining the selectivity of pharmacological tools, which may have been over-estimated in the past, and highlights the need to find more selective agonists to investigate 5-HT2 receptor pharmacology.

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References

Vickers S, Dourish C, Kennett G . Evidence that hypophagia induced by d-fenfluramine and d-norfenfluramine in the rat is mediated by 5-HT2C receptors. Neuropharmacology. 2001; 41(2):200-9. DOI: 10.1016/s0028-3908(01)00063-6. View

Kennett G, Wood M, Bright F, Cilia J, Piper D, Gager T . In vitro and in vivo profile of SB 206553, a potent 5-HT2C/5-HT2B receptor antagonist with anxiolytic-like properties. Br J Pharmacol. 1996; 117(3):427-434. PMC: 1909304. DOI: 10.1111/j.1476-5381.1996.tb15208.x. View

Kennett G, Ainsworth K, Trail B, Blackburn T . BW 723C86, a 5-HT2B receptor agonist, causes hyperphagia and reduced grooming in rats. Neuropharmacology. 1997; 36(2):233-9. DOI: 10.1016/s0028-3908(96)00171-2. View

Martin G, Humphrey P . Receptors for 5-hydroxytryptamine: current perspectives on classification and nomenclature. Neuropharmacology. 1994; 33(3-4):261-73. DOI: 10.1016/0028-3908(94)90058-2. View

Humphrey P, Hartig P, Hoyer D . A proposed new nomenclature for 5-HT receptors. Trends Pharmacol Sci. 1993; 14(6):233-6. DOI: 10.1016/0165-6147(93)90016-d. View

Ismaiel A, De Los Angeles J, Teitler M, Ingher S, Glennon R . Antagonism of 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane stimulus with a newly identified 5-HT2- versus 5-HT1C-selective antagonist. J Med Chem. 1993; 36(17):2519-25. DOI: 10.1021/jm00069a010. View

Baxter G, Kennett G, Blaney F, Blackburn T . 5-HT2 receptor subtypes: a family re-united?. Trends Pharmacol Sci. 1995; 16(3):105-10. DOI: 10.1016/s0165-6147(00)88991-9. View

Baxter G, Murphy O, Blackburn T . Further characterization of 5-hydroxytryptamine receptors (putative 5-HT2B) in rat stomach fundus longitudinal muscle. Br J Pharmacol. 1994; 112(1):323-31. PMC: 1910288. DOI: 10.1111/j.1476-5381.1994.tb13072.x. View

Bromidge S, Dabbs S, DAVIES D, Davies S, Duckworth D, Forbes I . Model studies on a synthetically facile series of N-substituted phenyl-N'-pyridin-3-yl ureas leading to 1-(3-pyridylcarbamoyl) indolines that are potent and selective 5-HT(2C/2B) receptor antagonists. Bioorg Med Chem. 2000; 7(12):2767-73. DOI: 10.1016/s0968-0896(99)00228-x. View

10.

Setola V, Hufeisen S, Grande-Allen K, Vesely I, Glennon R, Blough B . 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") induces fenfluramine-like proliferative actions on human cardiac valvular interstitial cells in vitro. Mol Pharmacol. 2003; 63(6):1223-9. DOI: 10.1124/mol.63.6.1223. View

11.

Sadzot B, Baraban J, Glennon R, Lyon R, Leonhardt S, Jan C . Hallucinogenic drug interactions at human brain 5-HT2 receptors: implications for treating LSD-induced hallucinogenesis. Psychopharmacology (Berl). 1989; 98(4):495-9. DOI: 10.1007/BF00441948. View

12.

Hoyer D, Clarke D, Fozard J, Hartig P, Martin G, Mylecharane E . International Union of Pharmacology classification of receptors for 5-hydroxytryptamine (Serotonin). Pharmacol Rev. 1994; 46(2):157-203. View

13.

Leonhardt S, Gorospe E, HOFFMAN B, Teitler M . Molecular pharmacological differences in the interaction of serotonin with 5-hydroxytryptamine1C and 5-hydroxytryptamine2 receptors. Mol Pharmacol. 1992; 42(2):328-35. View

14.

Nelson D, Lucaites V, Wainscott D, Glennon R . Comparisons of hallucinogenic phenylisopropylamine binding affinities at cloned human 5-HT2A, -HT(2B) and 5-HT2C receptors. Naunyn Schmiedebergs Arch Pharmacol. 1999; 359(1):1-6. DOI: 10.1007/pl00005315. View

15.

Sleight A, Stam N, Mutel V, Vanderheyden P . Radiolabelling of the human 5-HT2A receptor with an agonist, a partial agonist and an antagonist: effects on apparent agonist affinities. Biochem Pharmacol. 1996; 51(1):71-6. DOI: 10.1016/0006-2952(95)02122-1. View

16.

Quirk K, Lawrence A, Jones J, Misra A, Harvey V, Lamb H . Characterisation of agonist binding on human 5-HT2C receptor isoforms. Eur J Pharmacol. 2001; 419(2-3):107-12. DOI: 10.1016/s0014-2999(01)00943-8. View

17.

Lopez-Gimenez J, Villazon M, Brea J, Loza M, Palacios J, Mengod G . Multiple conformations of native and recombinant human 5-hydroxytryptamine(2a) receptors are labeled by agonists and discriminated by antagonists. Mol Pharmacol. 2001; 60(4):690-9. View

18.

Porter R, Benwell K, Lamb H, Malcolm C, Allen N, Revell D . Functional characterization of agonists at recombinant human 5-HT2A, 5-HT2B and 5-HT2C receptors in CHO-K1 cells. Br J Pharmacol. 1999; 128(1):13-20. PMC: 1571597. DOI: 10.1038/sj.bjp.0702751. View

19.

Vickers S, Clifton P, Dourish C, Tecott L . Reduced satiating effect of d-fenfluramine in serotonin 5-HT(2C) receptor mutant mice. Psychopharmacology (Berl). 1999; 143(3):309-14. DOI: 10.1007/s002130050952. View

20.

Marek G, Aghajanian G . LSD and the phenethylamine hallucinogen DOI are potent partial agonists at 5-HT2A receptors on interneurons in rat piriform cortex. J Pharmacol Exp Ther. 1996; 278(3):1373-82. View