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Kozyra P, Pitucha M. Terminal Phenoxy Group as a Privileged Moiety of the Drug Scaffold—A Short Review of Most Recent Studies 2013–2022. Int J Mol Sci 2022; 23:ijms23168874. [PMID: 36012142 PMCID: PMC9408176 DOI: 10.3390/ijms23168874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/03/2022] [Accepted: 08/07/2022] [Indexed: 11/16/2022] Open
Abstract
The terminal phenoxy group is a moiety of many drugs in use today. Numerous literature reports indicated its crucial importance for biological activity; thus, it is a privileged scaffold in medicinal chemistry. This review focuses on the latest achievements in the field of novel potential agents bearing a terminal phenoxy group in 2013–2022. The article provided information on neurological, anticancer, potential lymphoma agent, anti-HIV, antimicrobial, antiparasitic, analgesic, anti-diabetic as well as larvicidal, cholesterol esterase inhibitors, and antithrombotic or agonistic activities towards the adrenergic receptor. Additionally, for selected agents, the Structure–Activity–Relationship (SAR) is also discussed. Thus, this study may help the readers to better understand the nature of the phenoxy group, which will translate into rational drug design and the development of a more efficient drug. To the best of our knowledge, this is the first review devoted to an in-depth analysis of the various activities of compounds bearing terminal phenoxy moiety.
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Different Peas in the Same Pod: The Histaminergic Neuronal Heterogeneity. Curr Top Behav Neurosci 2021; 59:303-327. [PMID: 34455575 DOI: 10.1007/7854_2021_241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The histaminergic neuronal system is recently receiving increasing attention, as much has been learned over the past 25 years about histamine role as a neurotransmitter. Indeed, this amine is crucial in maintaining arousal and provides important contributions to regulate circadian rhythms, energy, endocrine homeostasis, motor behavior, and cognition. The extent to which these distinct physiological functions are operated by independent histamine neuronal subpopulation is unclear. In the rat brain histamine neuronal cell bodies are grouped within the tuberomamillary nucleus of the posterior hypothalamus in five clusters, E1-E5, each sending overlapping axons throughout the entire central nervous system with no strict topographical pattern. These features lead to the concept that histamine regulation of a wide range of functions in the central nervous system is achieved by the histaminergic neuronal system as a whole. However, increasing experimental evidence suggesting that the histaminergic system is organized into distinct pathways modulated by selective mechanisms challenges this view. In this review, we summarized experimental evidence supporting the heterogeneity of histamine neurons, and their organization in functionally distinct circuits impinging on separate brain regions and displaying selective control mechanisms. This implies independent functions of subsets of histaminergic neurons according to their respective origin and terminal projections with relevant consequences for the development of specific compounds that affect only subsets of histamine neurons, thus increasing the target specificity.
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Pontiki E, Hadjipavlou-Litina D. QSAR models on H4 receptor antagonists associated with inflammation and anaphylaxis. J Biomol Struct Dyn 2016; 35:968-1005. [DOI: 10.1080/07391102.2016.1166986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Eleni Pontiki
- Department of Pharmaceutical Chemistry, School of Pharmacy, Aristotle University of Thessaloniki , Thessaloniki 54124, Greece
| | - Dimitra Hadjipavlou-Litina
- Department of Pharmaceutical Chemistry, School of Pharmacy, Aristotle University of Thessaloniki , Thessaloniki 54124, Greece
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Wilson DM, Apps J, Bailey N, Bamford MJ, Beresford IJ, Brackenborough K, Briggs MA, Brough S, Calver AR, Crook B, Davis RK, Davis RP, Davis S, Dean DK, Harris L, Heslop T, Holland V, Jeffrey P, Panchal TA, Parr CA, Quashie N, Schogger J, Sehmi SS, Stean TO, Steadman JG, Trail B, Wald J, Worby A, Takle AK, Witherington J, Medhurst AD. Identification of clinical candidates from the benzazepine class of histamine H3 receptor antagonists. Bioorg Med Chem Lett 2013; 23:6890-6. [DOI: 10.1016/j.bmcl.2013.09.090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 10/26/2022]
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Wilson DM, Apps J, Bailey N, Bamford MJ, Beresford IJ, Briggs MA, Calver AR, Crook B, Davis RP, Davis S, Dean DK, Harris L, Heightman TD, Panchal T, Parr CA, Quashie N, Steadman JG, Schogger J, Sehmi SS, Stean TO, Takle AK, Trail BK, White T, Witherington J, Worby A, Medhurst AD. The discovery of the benzazepine class of histamine H3 receptor antagonists. Bioorg Med Chem Lett 2013; 23:6897-901. [DOI: 10.1016/j.bmcl.2013.09.089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 11/16/2022]
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Kuhne S, Wijtmans M, Lim HD, Leurs R, de Esch IJP. Several down, a few to go: histamine H3 receptor ligands making the final push towards the market? Expert Opin Investig Drugs 2011; 20:1629-48. [PMID: 21992603 DOI: 10.1517/13543784.2011.625010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The histamine H(3) receptor (H(3)R) plays a pivotal role in a plethora of therapeutic areas. Blocking the H(3)R with antagonists/inverse agonists has been postulated to be of broad therapeutic use. Indeed, H(3)R antagonists/inverse agonists have been extensively evaluated in the clinic. AREAS COVERED Here, we address new developments, insights obtained and challenges encountered in the clinical evaluations. For recent H(3)R clinical candidates, the status and results of the corresponding clinical trial(s) will be discussed along with preclinical data. MAIN FINDINGS In all, it becomes evident that clinical evaluation of H(3)R antagonists/inverse agonists is characterized by mixed results. On one hand, Pitolisant has successfully passed several Phase II trials and seems to be the most advanced compound in the clinic now, being in Phase III. On the other hand, some compounds (e.g., PF-03654647 and MK-0249) failed at Phase II clinical level for several indications. EXPERT OPINION A challenging feature in H(3)R research is the multifaceted role of the receptor at a molecular/biochemical level, which can complicate targeting by small molecules at several (pre)clinical levels. Accordingly, H(3)R antagonists/inverse agonists require further testing to pinpoint the determinants for clinical efficacy and to aid in the final push towards the market.
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Affiliation(s)
- Sebastiaan Kuhne
- VU University Amsterdam, Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Department of Pharmacochemistry, Faculty of Exact Sciences, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
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Igel P, Geyer R, Strasser A, Dove S, Seifert R, Buschauer A. Synthesis and structure-activity relationships of cyanoguanidine-type and structurally related histamine H4 receptor agonists. J Med Chem 2009; 52:6297-313. [PMID: 19791743 DOI: 10.1021/jm900526h] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently, we identified high-affinity human histamine H3 (hH3R) and H4 receptor (hH4R) ligands among a series of NG-acylated imidazolylpropylguanidines, which were originally designed as histamine H2 receptor (H2R) agonists. Aiming at selectivity for hH4R, the acylguanidine group was replaced with related moieties. Within a series of cyanoguanidines, 2-cyano-1-[4-(1H-imidazol-4-yl)butyl]-3-[(2-phenylthio)ethyl]guanidine (UR-PI376, 67) was identified as the most potent hH4R agonist (pEC50 = 7.47, alpha = 0.93) showing negligible hH1R and hH2R activities and significant selectivity over the hH3R (pKB = 6.00, alpha = -0.28), as determined in steady-state GTPase assays using membrane preparations of hH(x)R-expressing Sf9 cells. In contrast to previously described selective H4R agonists, this compound and other 3-substituted derivatives are devoid of agonistic activity at the other HR subtypes. Modeling of the binding mode of 67 suggests that the cyanoguanidine moiety forms charge-assisted hydrogen bonds not only with the conserved Asp-94 but also with the hH4R-specific Arg-341 residue. 2-Carbamoyl-1-[2-(1H-imidazol-4-yl)ethyl]-3-(3-phenylpropyl)guanidine (UR-PI97, 88) was unexpectedly identified as a highly potent and selective hH3R inverse agonist (pKB = 8.42, >300-fold selectivity over the other HR subtypes).
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Affiliation(s)
- Patrick Igel
- Department of Pharmaceutical/Medicinal Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitatsstrasse 31, D-93053 Regensburg, Germany
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Foley AG, Prendergast A, Barry C, Scully D, Upton N, Medhurst AD, Regan CM. H3 receptor antagonism enhances NCAM PSA-mediated plasticity and improves memory consolidation in odor discrimination and delayed match-to-position paradigms. Neuropsychopharmacology 2009; 34:2585-600. [PMID: 19657331 DOI: 10.1038/npp.2009.89] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
To further understand the procognitive actions of GSK189254, a histamine H(3) receptor antagonist, we determined its influence on the modulation of hippocampal neural cell adhesion molecule (NCAM) polysialylation (PSA) state, a necessary neuroplastic mechanism for learning and memory consolidation. A 4-day treatment with GSK189254 significantly increased basal expression of dentate polysialylated cells in rats with the maximal effect being observed at 0.03-0.3 mg/kg. At the optimal dose (0.3 mg/kg), GSK189254 enhanced water maze learning and the associated transient increase in NCAM-polysialylated cells. The increase in dentate polysialylated cell frequency induced by GSK189254 was not attributable to enhanced neurogenesis, although it did induce a small, but significant, increase in the survival of these newborn cells. GSK189254 (0.3 mg/kg) was without effect on polysialylated cell frequency in the entorhinal and perirhinal cortex, but significantly increased the diffuse PSA staining observed in the anterior, ventromedial, and dorsomedial aspects of the hypothalamus. Consistent with its ability to enhance the learning-associated, post-training increases in NCAM PSA state, GSK189254 (0.3 mg/kg) reversed the amnesia induced by scopolamine given in the 6-h post-training period after training in an odor discrimination paradigm. Moreover, GSK189254 significantly improved the performance accuracy of a delayed match-to-position paradigm, a task dependent on the prefrontal cortex and degree of cortical arousal, the latter may be related to enhanced NCAM PSA-associated plasticity in the hypothalamus. The procognitive actions of H3 antagonism combined with increased NCAM PSA expression may exert a disease-modifying action in conditions harboring fundamental deficits in NCAM-mediated neuroplasticity, such as schizophrenia and Alzheimer's disease.
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Affiliation(s)
- Andrew G Foley
- Berand Neuropharmacology, NovaUCD, Belfield Innovation Park, University College Dublin, Dublin, Ireland
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9
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Wijtmans M, Celanire S, Snip E, Gillard MR, Gelens E, Collart PP, Venhuis BJ, Christophe B, Hulscher S, van der Goot H, Lebon F, Timmerman H, Bakker RA, Lallemand BILF, Leurs R, Talaga PE, de Esch IJP. 4-benzyl-1H-imidazoles with oxazoline termini as histamine H3 receptor agonists. J Med Chem 2008; 51:2944-53. [PMID: 18433114 DOI: 10.1021/jm7014149] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Research on the therapeutic applications of the histamine H3 receptor (H3R) has traditionally focused on antagonists/inverse agonists. In contrast, H3R agonists have received less attention despite their potential use in several disease areas. The lower availability of H3R agonists not only hampers their full therapeutic exploration, it also prevents an unequivocal understanding of the structural requirements for H3R activation. In the light of these important issues, we present our findings on 4-benzyl-1H-imidazole-based H3R agonists. Starting from two high throughput screen hits (10 and 11), the benzyl side chain was altered with lipophilic groups using combinatorial and classical chemical approaches (compounds 12-31). Alkyne- or oxazolino-substituents gave excellent affinities and agonist activities up to the single digit nM range. Our findings further substantiate the growing notion that basic ligand sidechains are not necessary for H 3R activation and reveal the oxazolino group as a hitherto unexplored functional group in H3R research.
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Affiliation(s)
- Maikel Wijtmans
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Faculty of Exact Sciences, VU University Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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Wijtmans M, Leurs R, de Esch I. Histamine H3 receptor ligands break ground in a remarkable plethora of therapeutic areas. Expert Opin Investig Drugs 2007; 16:967-85. [PMID: 17594183 DOI: 10.1517/13543784.16.7.967] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The neurotransmitter histamine exerts its action through four distinct histamine receptors. The histamine H(1) and H(2) receptor are well established drug targets, whereas the histamine H(4) receptor is undergoing rigorous characterisation at present. The histamine H(3) receptor (H(3)R) is a G(i/o)-protein coupled receptor and is mostly expressed in the CNS. A remarkably large and different array of therapeutic areas, in which ligands for the H(3)R may prove useful, has been identified and a massive research undertaking is underway to substantiate the high expectations for H(3)R ligands. At present, several ligands for the H(3)R are being evaluated in clinical studies. In this review, the many potential therapeutic areas for H(3)R antagonists, inverse agonists and agonists is discussed. Promising medicinal chemistry and toxicological developments, as well as the advancement of several H(3)R ligands into the clinic, will be highlighted. This review also describes the problems that have been overcome and the questions that remain in developing H(3)R-related drugs. Considering the tremendous efforts by industry, it can be expected that the first H(3)R drugs will reach the market soon.
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Affiliation(s)
- Maikel Wijtmans
- Vrije Universiteit Amsterdam, Leiden/Amsterdam Center of Drug Research, Division of Medicinal Chemistry, Faculty of Sciences, De Boelelaan 1083, Amsterdam, The Netherlands
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Medhurst AD, Atkins AR, Beresford IJ, Brackenborough K, Briggs MA, Calver AR, Cilia J, Cluderay JE, Crook B, Davis JB, Davis RK, Davis RP, Dawson LA, Foley AG, Gartlon J, Gonzalez MI, Heslop T, Hirst WD, Jennings C, Jones DNC, Lacroix LP, Martyn A, Ociepka S, Ray A, Regan CM, Roberts JC, Schogger J, Southam E, Stean TO, Trail BK, Upton N, Wadsworth G, Wald JA, White T, Witherington J, Woolley ML, Worby A, Wilson DM. GSK189254, a Novel H3 Receptor Antagonist That Binds to Histamine H3 Receptors in Alzheimer's Disease Brain and Improves Cognitive Performance in Preclinical Models. J Pharmacol Exp Ther 2007; 321:1032-45. [PMID: 17327487 DOI: 10.1124/jpet.107.120311] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
6-[(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254) is a novel histamine H(3) receptor antagonist with high affinity for human (pK(i) = 9.59 -9.90) and rat (pK(i) = 8.51-9.17) H(3) receptors. GSK189254 is >10,000-fold selective for human H(3) receptors versus other targets tested, and it exhibited potent functional antagonism (pA(2) = 9.06 versus agonist-induced changes in cAMP) and inverse agonism [pIC(50) = 8.20 versus basal guanosine 5'-O-(3-[(35)S]thio)triphosphate binding] at the human recombinant H(3) receptor. In vitro autoradiography demonstrated specific [(3)H]GSK189254 binding in rat and human brain areas, including cortex and hippocampus. In addition, dense H(3) binding was detected in medial temporal cortex samples from severe cases of Alzheimer's disease, suggesting for the first time that H(3) receptors are preserved in late-stage disease. After oral administration, GSK189254 inhibited cortical ex vivo R-(-)-alpha-methyl[imidazole-2,5(n)-(3)H]histamine dihydrochloride ([(3)H]R-alpha-methylhistamine) binding (ED(50) = 0.17 mg/kg) and increased c-Fos immunoreactivity in prefrontal and somatosensory cortex (3 mg/kg). Microdialysis studies demonstrated that GSK189254 (0.3-3 mg/kg p.o.) increased the release of acetylcholine, noradrenaline, and dopamine in the anterior cingulate cortex and acetylcholine in the dorsal hippocampus. Functional antagonism of central H(3) receptors was demonstrated by blockade of R-alpha-methylhistamine-induced dipsogenia in rats (ID(50) = 0.03 mg/kg p.o.). GSK189254 significantly improved performance of rats in diverse cognition paradigms, including passive avoidance (1 and 3 mg/kg p.o.), water maze (1 and 3 mg/kg p.o.), object recognition (0.3 and 1 mg/kg p.o.), and attentional set shift (1 mg/kg p.o.). These data suggest that GSK189254 may have therapeutic potential for the symptomatic treatment of dementia in Alzheimer's disease and other cognitive disorders.
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Affiliation(s)
- Andrew D Medhurst
- Neurology and GI Centre of Excellence for Drug Discovery, GlaxoSmithKline, Third Ave., Harlow, Essex, CM19 5AW, UK.
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12
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Chai W, Breitenbucher JG, Kwok A, Li X, Wong V, Carruthers NI, Lovenberg TW, Mazur C, Wilson SJ, Axe FU, Jones TK. Non-imidazole heterocyclic histamine H3 receptor antagonists. Bioorg Med Chem Lett 2003; 13:1767-70. [PMID: 12729661 DOI: 10.1016/s0960-894x(03)00299-3] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Continued exploration of the SAR around the lead imidazopyridine histamine H(3) antagonist 1 has led to the discovery of several related series of heterocyclic histamine H(3) antagonists. The synthesis and SAR of indolizine, indole and pyrazolopyridine based compounds are now described.
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Affiliation(s)
- Wenying Chai
- Johnson & Johnson Pharmaceutical Research and Development L. L. C., 3210 Merryfield Row, San Diego, CA 92121, USA.
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Weber B, Schlicker E. Modulation of dopamine release in the guinea-pig retina by G(i)- but not by G(s)- or G(q)-protein-coupled receptors. Fundam Clin Pharmacol 2001; 15:393-400. [PMID: 11860527 DOI: 10.1046/j.1472-8206.2001.00056.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The modulation of dopamine release from the guinea-pig retina was studied using maximally effective concentrations of 10 agonists acting on G(i)-, G(s)- or G(q)-protein-coupled receptors (PCRs). Retinal discs were preincubated with [(3)H]noradrenaline and superfused; tritium overflow was evoked electrically. The following compounds acting on G(i)-PCRs reduced the tritium overflow, which represents quasi-physiological dopamine release under the experimental conditions of our study: the dopamine and alpha(2)-adrenoceptor agonist B-HT 920 by 95%, the muscarinic agonist oxotremorine by 96%, melatonin by 94%, the cannabinoid agonist WIN 55,212-2 by 71% and histamine by 66%. Tritium overflow was not affected by serotonin or by agonists acting on G(s)-PCRs (ACTH1-24 and the beta-adrenoceptor agonist procaterol) and G(q)-PCRs (angiotensin II and bradykinin). The effects of B-HT 920, oxotremorine and melatonin were studied in more detail using appropriate antagonists. The inhibitory effect of a submaximally active concentration of B-HT 920 was counteracted by the dopamine D(2/3) antagonist haloperidol but not affected by the alpha(2)-adrenoceptor antagonist phentolamine. The muscarinic antagonist atropine shifted to the right the concentration-response curve of oxotremorine (pA(2) 8.7) and the melatonin MT(2) antagonist 4-P-PDOT produced a rightward shift of the concentration-response curve of melatonin (pA(2) 10.6). Melatonin was also studied in superfused brain slices (from the guinea-pig) preincubated with [(3)H]noradrenaline. The electrically evoked tritium overflow in cerebrocortical, hippocampal and hypothalamic slices (representing quasi-physiological noradrenaline release) and in striatal slices (representing quasi-physiological dopamine release) was not affected by melatonin at a concentration that causes the maximum effect in retinal discs. In conclusion, dopamine release in the guinea-pig retina is inhibited via G(i)-PCRs including dopamine (D(2/3)), muscarinic and melatonin (MT(2)) receptors but not affected via any of the G(s)- or G(q)-PCRs under study. Unlike in the retina, melatonin fails to inhibit monoamine release in four brain regions of the guinea-pig.
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Affiliation(s)
- B Weber
- Department of Pharmacology and Toxicology, University of Bonn, Reuterstr. 2b, 53113 Bonn, Germany
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Weber B, Schlicker E, Sokoloff P, Stark H. Identification of the dopamine autoreceptor in the guinea-pig retina as D(2) receptor using novel subtype-selective antagonists. Br J Pharmacol 2001; 133:1243-8. [PMID: 11498509 PMCID: PMC1621144 DOI: 10.1038/sj.bjp.0704192] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Dopamine release in the retina is subject to modulation via autoreceptors, which belong to the D(2) receptor family (encompassing the D(2), D(3) and D(4) receptors). The aim of the present study was to determine the receptor subtype (D(2) vs D(3)) involved in the inhibition of dopamine release in guinea-pig retinal discs, using established (haloperidol, (S)-nafadotride) and novel dopamine receptor antagonists (ST-148, ST-198). 2. hD(2L) and hD(3) receptors were expressed in CHO cells and the pK(i) values determined in binding studies with [(125)I]-iodosulpride were: haloperidol 9.22 vs 8.54; ST-148 7.85 vs 6.60; (S)-nafadotride 8.52 vs 9.51; ST-198 6.14 vs 7.92. 3. The electrically evoked tritium overflow from retinal discs preincubated with [(3)H]-noradrenaline (which represents quasi-physiological dopamine release) was inhibited by the dopamine receptor agonists B-HT 920 (talipexole) and quinpirole (maximally by 82 and 71%; pEC(50) 5.80 and 5.83). The concentration-response curves of these agonists were shifted to the right by haloperidol (apparent pA(2) 8.69 and 8.23) and ST-148 (7.52 and 7.66). (S)-Nafadotride 0.01 microM and ST-198 0.32 microM did not affect the concentration-response curve of B-HT 920. 4. The dopamine autoreceptor in the guinea-pig retina can be classified as a D(2) receptor. ST-148 and ST-198 show an improved selectivity for D(2) and D(3) receptors when compared to haloperidol and (S)-nafadotride, respectively.
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Affiliation(s)
- Bernd Weber
- Institut für Pharmakologie und Toxikologie, Universität Bonn, Reuterstr. 2b, 53113 Bonn, Germany
| | - Eberhard Schlicker
- Institut für Pharmakologie und Toxikologie, Universität Bonn, Reuterstr. 2b, 53113 Bonn, Germany
- Author for correspondence:
| | - Pierre Sokoloff
- Unité de Neurobiologie et de Pharmacologie Moléculaire, Centre Paul Broca de l'INSERM (U. 109), 2 ter rue d'Alésia, 75014 Paris, France
| | - Holger Stark
- Institut für Pharmazeutische Chemie, Biozentrum, Johann Wolfgang Goethe-Universität Frankfurt am Main, Marie-Curie-Str. 9, 60439 Frankfurt am Main, Germany
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De Esch IJ, Gaffar A, Menge WM, Timmerman H. Synthesis and histamine H3 receptor activity of 4-(n-alkyl)-1H-imidazoles and 4-(omega-phenylalkyl)-1H-imidazoles. Bioorg Med Chem 1999; 7:3003-9. [PMID: 10658607 DOI: 10.1016/s0968-0896(99)00253-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The influence of lipophilic moieties attached to a 4-1H-imidazole ring on the histamine H3 receptor activity was systematically investigated. Series of 4-(n-alkyl)-1H-imidazoles and 4-(omega-phenylalkyl)-1H-imidazoles were prepared, with an alkyl chain varying from 2-9 methylene groups and from 1-9 methylene groups, respectively. The compounds were tested for their activity on the H3 receptor under in vitro conditions. For the 4-(n-alkyl)-1H-imidazoles the activity is proportional to chain length, ranging from a pA2 value of 6.3 +/- 0.2 for 4-(n-propyl)-1H-imidazole to a pA2 value of 7.2 +/- 0.1 for 4-(n-decyl)-1H-imidazole. For the series 4-(omega-phenylalkyl)-4H-imidazoles an optimum in H3 activity was found for the pentylene spacer: 4-(omega-phenylpentyl)-1H-imidazole has a pA2 value of 7.8 +/- 0.1.
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Affiliation(s)
- I J De Esch
- Leiden/Amsterdam Center for Drug Research, Department of Pharmacochemistry, Faculty of Chemistry, Vrije Universiteit, Amsterdam, The Netherlands
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