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Kinobe RT, Miyake Y. Evaluating the anti-inflammatory and analgesic properties of maropitant: A systematic review and meta-analysis. Vet J 2020; 259-260:105471. [PMID: 32553233 DOI: 10.1016/j.tvjl.2020.105471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 05/06/2020] [Accepted: 05/06/2020] [Indexed: 12/09/2022]
Abstract
The neurotransmitter Substance P, and its neurokinin-1 receptor (NK-1R) are involved in the regulation of many pathophysiological processes including emesis, inflammation and nociceptive processing. This review provides a brief summary of the anti-inflammatory and analgesic properties of experimental NK-1R antagonists followed by a systematic review and meta-analysis on maropitant, the only NK-1R antagonist with a label indication for emesis in veterinary patients. There is very limited evidence based information on the putative clinical utilisation of maropitant for pain and inflammation. The aim of this systematic review and meta-analysis was to evaluate published reports on anti-inflammatory, analgesic and anaesthesia-sparing effects of maropitant. Medline, Pubmed, Science direct and Web of Science were searched to identify all published studies on maropitant, followed by a meta-analysis. Fourteen studies with 128 animals receiving maropitant and 127 controls met the inclusion criteria. Overall, maropitant had a significant inhalation anaesthetic-sparing effect (SMD -0.92, 95% CI -1.30, -0.54; P < 0.00001). However, treatment with maropitant had no effect on pain (SMD 0.06, 95% CI -0.37, 0.48; P = 0.80), or leukocyte cell infiltration in different inflammatory conditions (SMD -0.60, 95% CI -1.31, 0.11; P = 0.10). Based on all eligible studies for this review, it can be deduced that maropitant significantly reduced the minimum alveolar concentrations for isoflurane and sevoflurane for many different surgical procedures but it had no clearly proven effect on inflammation and pain.
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Affiliation(s)
- R T Kinobe
- College of Public Health, Medical and Veterinary Sciences, Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Solander Drive, Townsville, Queensland 4811, Australia.
| | - Y Miyake
- Veterinary Clinical Sciences, College of Public Health, Medical and Veterinary Sciences, James Cook University, Solander Drive, Townsville, Queensland 4811, Australia
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Harte SE, Meyers JB, Donahue RR, Taylor BK, Morrow TJ. Mechanical Conflict System: A Novel Operant Method for the Assessment of Nociceptive Behavior. PLoS One 2016; 11:e0150164. [PMID: 26915030 PMCID: PMC4767889 DOI: 10.1371/journal.pone.0150164] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/10/2016] [Indexed: 11/19/2022] Open
Abstract
A new operant test for preclinical pain research, termed the Mechanical Conflict System (MCS), is presented. Rats were given a choice either to remain in a brightly lit compartment or to escape to a dark compartment by crossing an array of height-adjustable nociceptive probes. Latency to escape the light compartment was evaluated with varying probe heights (0, .5, 1, 2, 3, and 4 mm above compartment floor) in rats with neuropathic pain induced by constriction nerve injury (CCI) and in naive control rats. Escape responses in CCI rats were assessed following intraperitoneal administration of pregabalin (10 and 30 mg/kg), morphine (2.5 and 5 mg/kg), and the tachykinin NK1 receptor antagonist, RP 67580 (1 and 10 mg/kg). Results indicate that escape latency increased as a function of probe height in both naive and CCI rats. Pregabalin (10 and 30 mg/kg) and morphine (5 mg/kg), but not RP 67580, decreased latency to escape in CCI rats suggesting an antinociceptive effect. In contrast, morphine (10 mg/kg) but not pregabalin (30 mg/kg) increased escape latency in naive rats suggesting a possible anxiolytic action of morphine in response to light-induced fear. No order effects following multiple test sessions were observed. We conclude that the MCS is a valid method to assess behavioral signs of affective pain in rodents.
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Affiliation(s)
- Steven E. Harte
- Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
- * E-mail:
| | - Jessica B. Meyers
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
| | - Renee R. Donahue
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Bradley K. Taylor
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Thomas J. Morrow
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
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Abstract
The cannabinoid receptors are G protein-coupled receptors activated by endocannabinoids or exogenous agonist such as tetrahydrocannabinol. Upon agonist binding, cannabinoid receptors will activate G proteins of the Gi family, which in turn inhibits adenylyl cyclase. Recently, inverse agonists and neutral antagonist for cannabinoid receptors have been discovered, demonstrating constitutive activity of the cannabinoid receptors. This chapter will discuss the current state of the art and provide a framework for evaluating constitutive receptor activity and distinguishing constitutive receptor activity from constitutive endogenous agonist tone.
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Endo T, Saijo T, Haneda E, Maeda J, Tokunaga M, Zhang MR, Kannami A, Asai H, Suzuki M, Suhara T, Higuchi M. Quantification of central substance P receptor occupancy by aprepitant using small animal positron emission tomography. Int J Neuropsychopharmacol 2015; 18:pyu030. [PMID: 25609595 PMCID: PMC4368889 DOI: 10.1093/ijnp/pyu030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Central substance P receptors, termed NK-1 receptors, have been considered as therapeutic targets in the development of drugs against diverse conditions, including emesis, overactive bladder, and depression. METHODS Here, we applied small animal positron emission tomography (PET) and a radioligand for NK-1 receptors ([(18)F]FE-SPA-RQ) for measuring occupancies of these receptors by a selective antagonist (aprepitant) in order to examine the validity of this in vivo imaging system for preclinical characterization of candidate agents acting on NK-1 receptors, and as a tool for predicting optimal doses in humans. RESULTS PET in gerbils depicted high uptake in the striatum and dose-dependent displacement with increasing doses of aprepitant. Occupancies increased as a function of aprepitant plasma concentrations according to a one-site competition model, which agrees with reported occupancy-concentration relationships in clinical studies after correction for species differences in plasma protein-unbound aprepitant fractions. These occupancy data were further supported by ex vivo autoradiography of brain samples from aprepitant-treated gerbils. In a pilot study of a marmoset, we obtained more accurate determinations of NK-1 receptor occupancy, less affected by spillover of signals from extracranial tissues than in gerbil experiments. CONCLUSIONS These findings support the utility of small animals and quantitative PET in the development of drugs targeting NK-1 receptors.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Makoto Higuchi
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan (Drs Endo, Saijo, Haneda, Maeda, Tokunaga, Zhang, Suhara, Higuchi); Department of Molecular Neuroimaging, Tohoku University Graduate School of Medicine, Sendai, Japan (Drs Endo, Saijo, Suhara, and Higuchi); DMPK Research Laboratory, Mitsubishi Tanabe Pharma Corporation, Kisarazu, Japan (Drs Endo, Saijo, and Kannami); Clinical & Research Quality Assurance Department, Mitsubishi Tanabe Pharma Corporation, Tokyo, Japan (Dr Asai); Clinical Pharmacology Department, Mitsubishi Tanabe Pharma Corporation, Tokyo, Japan (Dr Suzuki).
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Involvement of substance P and the NK-1 receptor in human pathology. Amino Acids 2014; 46:1727-50. [PMID: 24705689 DOI: 10.1007/s00726-014-1736-9] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 03/23/2014] [Indexed: 10/25/2022]
Abstract
The peptide substance P (SP) shows a widespread distribution in both the central and peripheral nervous systems, but it is also present in cells not belonging to the nervous system (immune cells, liver, lung, placenta, etc.). SP is located in all body fluids, such as blood, cerebrospinal fluid, breast milk, etc. i.e. it is ubiquitous in human body. After binding to the neurokinin-1 (NK-1) receptor, SP regulates many pathophysiological functions in the central nervous system, such as emotional behavior, stress, depression, anxiety, emesis, vomiting, migraine, alcohol addiction, seizures and neurodegeneration. SP has been also implicated in pain, inflammation, hepatitis, hepatotoxicity, cholestasis, pruritus, myocarditis, bronchiolitis, abortus, bacteria and viral infection (e.g., HIV infection) and it plays an important role in cancer (e.g., tumor cell proliferation, antiapoptotic effects in tumor cells, angiogenesis, migration of tumor cells for invasion, infiltration and metastasis). This means that the SP/NK-1 receptor system is involved in the molecular bases of many human pathologies. Thus, knowledge of this system is the key for a better understanding and hence a better management of many human diseases. In this review, we update the involvement of the SP/NK-1 receptor system in the physiopathology of the above-mentioned pathologies and we suggest valuable future therapeutic interventions involving the use of NK-1 receptor antagonists, particularly in the treatment of emesis, depression, cancer, neural degeneration, inflammatory bowel disease, viral infection and pruritus, in which that system is upregulated.
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: G protein-coupled receptors. Br J Pharmacol 2013; 170:1459-581. [PMID: 24517644 PMCID: PMC3892287 DOI: 10.1111/bph.12445] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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López-Bellido R, Barreto-Valer K, Rodríguez RE. Expression of tachykinin receptors (tacr1a and tacr1b) in zebrafish: influence of cocaine and opioid receptors. J Mol Endocrinol 2013; 50:115-29. [PMID: 23256992 DOI: 10.1530/jme-12-0199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Opioid and tachykinin receptors (TACRs) are closely related in addiction and pain processes. In zebrafish, opioid receptors have been cloned and characterized both biochemically and pharmacologically. However, the tacr1 gene has not yet been described in zebrafish. The aim of this research was to identify the tacr1 gene, study the effects of cocaine on tacr1, and analyze the interaction between tacr1 and opioid receptors. We have identified a duplicate of tacr1 gene in zebrafish, designated as tacr1a and tacr1b. Phylogenetic analyses revealed an alignment of these receptors in the Tacr1 fish cluster, with a clear distinction from other TACR1s of amphibians, birds, and mammals. Our qPCR results showed that tacr1a and tacr1b mRNAs are expressed during embryonic development. Whole-mount in situ hybridization showed tacr1 expression in the CNS and in the peripheral tissues. Cocaine (1.5 μM) induced an upregulation of tacr1a and tacr1b at 24 and 48 h post-fertilization (hpf; except for tacr1a at 48 hpf, which was downregulated). By contrast, HEK-293 cells transfected with tacr1a and tacr1b and exposed to cocaine showed a downregulation of tacr1s. The knockdown of ZfDOR2 and ZfMOR, opioid receptors, induced a down- and upregulation of tacr1a and tacr1b respectively. In conclusion, tacr1a and tacr1b in zebrafish are widely expressed throughout the CNS and peripherally, suggesting a critical role of these tacr1s during embryogenesis. tacr1a and tacr1b mRNA expression is altered by cocaine exposure and by the knockdown of opioid receptors. Thus, zebrafish can provide clues for a better understanding of the relationship between tachykinin and opioid receptors in pain and addiction during embryonic development.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Line
- Cloning, Molecular
- Cocaine/pharmacology
- Gene Expression Regulation
- Gene Expression Regulation, Developmental/drug effects
- Gene Knockdown Techniques
- HEK293 Cells
- Humans
- Molecular Sequence Data
- Phylogeny
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Receptors, Opioid/genetics
- Receptors, Opioid/metabolism
- Receptors, Tachykinin/classification
- Receptors, Tachykinin/genetics
- Sequence Alignment
- Transfection
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish/metabolism
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Affiliation(s)
- Roger López-Bellido
- Department of Biochemistry and Molecular Biology, Institute of Neuroscience of Castilla y León, University of Salamanca, Salamanca, Spain
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Yoshino-Furukawa T, Maeda Y, Kikuchi A, Sakuma H, Imazumi K, Yamakuni H, Sogabe H, Matsuo M, Manda T, Uchida W. Pharmacological Properties of FK886, a New, Centrally Active Neurokinin-1 Receptor Antagonist. Biol Pharm Bull 2013; 36:76-81. [DOI: 10.1248/bpb.b12-00631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Yasue Maeda
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Aya Kikuchi
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Hiroyuki Sakuma
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Katsunori Imazumi
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Hisashi Yamakuni
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Hajime Sogabe
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Masahiko Matsuo
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Toshitaka Manda
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
| | - Wataru Uchida
- Pharmacology Research Laboratories, Drug Discovery Research, Astellas Pharma Inc
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Uehara H, Hocart SJ, González N, Mantey SA, Nakagawa T, Katsuno T, Coy DH, Jensen RT. The molecular basis for high affinity of a universal ligand for human bombesin receptor (BnR) family members. Biochem Pharmacol 2012; 84:936-48. [PMID: 22828605 DOI: 10.1016/j.bcp.2012.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 11/17/2022]
Abstract
There is increased interest in the Bn-receptor family because they are frequently over/ectopically expressed by tumors and thus useful as targets for imaging or receptor-targeted-cytotoxicity. The synthetic Bn-analog, [D-Tyr(6), β-Ala(11), Phe(13), Nle(14)]Bn(6-14) [Univ.Lig] has the unique property of having high affinity for all three human BNRs (GRPR, NMBR, BRS-3), and thus could be especially useful for this approach. However, the molecular basis of this property is unclear and is the subject of this study. To accomplish this, site-directed mutagenesis was used after identifying potentially important amino acids using sequence homology analysis of all BnRs with high affinity for Univ.Lig compared to the Cholecystokinin-receptor (CCK(A)R), which has low affinity. Using various criteria 74 amino acids were identified and 101 mutations made in GRPR by changing each to those of CCK(A)R or to alanine. 22 GRPR mutations showed a significant decrease in affinity for Univ.Lig (>2-fold) with 2 in EC2[D97N, G112V], 1 in UTM6[Y284A], 2 in EC4[R287N, H300S] showing >10-fold decrease in Univ.Lig affinity. Additional mutations were made to explore the molecular basis for these changes. Our results show that high affinity for Univ.Lig by human Bn-receptors requires positively charged amino acids in extracellular (EC)-domain 4 and to a lesser extent EC2 and EC3 suggesting charge-charge interactions may be particularly important for determining the general high affinity of this ligand. Furthermore, transmembrane amino acids particularly in UTM6 are important contributing both charge-charge interactions as well as interaction with a tyrosine residue in close proximity suggesting possible receptor-peptide cation-π or H-bonding interactions are also important for determining its high affinity.
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Affiliation(s)
- Hirotsugu Uehara
- Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892-1804, USA
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Duffy RA, Morgan C, Naylor R, Higgins GA, Varty GB, Lachowicz JE, Parker EM. Rolapitant (SCH 619734): A potent, selective and orally active neurokinin NK1 receptor antagonist with centrally-mediated antiemetic effects in ferrets. Pharmacol Biochem Behav 2012; 102:95-100. [DOI: 10.1016/j.pbb.2012.03.021] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 02/24/2012] [Accepted: 03/24/2012] [Indexed: 10/28/2022]
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Potentiation of brain stimulation reward by morphine: effects of neurokinin-1 receptor antagonism. Psychopharmacology (Berl) 2012; 220:215-24. [PMID: 21909635 PMCID: PMC3484369 DOI: 10.1007/s00213-011-2469-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 08/23/2011] [Indexed: 10/17/2022]
Abstract
RATIONALE The abuse potential of opioids may be due to their reinforcing and rewarding effects, which may be attenuated by neurokinin-1 receptor (NK1R) antagonists. OBJECTIVE This study was conducted to measure the effects of opioid and NK1R blockade on the potentiation of brain stimulation reward (BSR) by morphine using the intracranial self-stimulation method. METHODS Adult male C57BL/6J mice (n = 15) were implanted with unipolar stimulating electrodes in the lateral hypothalamus and trained to respond for varying frequencies of rewarding electrical stimulation. The BSR threshold (θ(0)) and maximum response rate (MAX) were determined before and after intraperitoneal administration of saline, morphine (1.0-17.0 mg/kg), or the NK1R antagonists L-733,060 (1.0-17.0 mg/kg) and L-703,606 (1.0-17.0 mg/kg). In morphine antagonism experiments, naltrexone (0.1-1.0 mg/kg) or 10.0 mg/kg L-733,060 or L-703,606 was administered 15 min before morphine (1.0-10.0 mg/kg) or saline. RESULTS Morphine dose-dependently decreased θ(0) (maximum effect = 62% of baseline) and altered MAX when compared to saline. L-703,606 and L-733,060 altered θ(0); 10.0 mg/kg L-733,060 and L-703,606, which did not affect θ(0) or MAX, attenuated the effects of 3.0 and 10.0 mg/kg morphine, and 1.0 and 0.3 mg/kg naltrexone blocked the effects of 10.0 mg/kg morphine. Naltrexone given before saline did not affect θ(0) or MAX. CONCLUSIONS The decrease in θ(0) by morphine reflects its rewarding effects, which were attenuated by NK1R and opioid receptor blockade. These results demonstrate the importance of substance P signaling during limbic reward system activation by opioids.
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Akasaka Y, Sakai A, Takasu K, Tsukahara M, Hatta A, Suzuki H, Inoue H. Suppressive effects of glycyrrhetinic acid derivatives on tachykinin receptor activation and hyperalgesia. J Pharmacol Sci 2011; 117:180-8. [PMID: 22032861 DOI: 10.1254/jphs.11116fp] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
Glycyrrhetinic acid (GA), an aglycone of glycyrrhizin, isolated from the licorice root (Glycyrrhizia), and its semi-synthetic derivatives have a wide range of pharmacological effects. To investigate whether GA derivatives may be used as a new class of analgesics, we examined the effects of these compounds on human tachykinin receptors expressed in CHO-K1 cells. Among the GA derivatives examined, the disodium salt of olean-11,13(18)-dien-3β,30-O-dihemiphthalate inhibited the mobilization of [Ca(2+)](i) induced by substance P, neurokinin A, and neurokinin B in CHO-K1 cells expressing the human NK(1), NK(2), and NK(3) tachykinin receptors, respectively. In an inflammatory pain model, Compound 5 suppressed the capsaicin-induced flinching behavior in a dose-dependent manner. Compound 5 was also effective in suppressing pain-related behaviors in the late phase of the formalin test and reducing thermal hyperalgesia in the neuropathic pain state caused by sciatic nerve injury. Collectively, Compound 5 may be an analgesic candidate via tachykinin receptor antagonism.
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Affiliation(s)
- Yuko Akasaka
- Research Laboratory, Minophagen Pharmaceutical Co., Ltd., Komatsubara, Zama, Kanagawa 252-0002, Japan
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14
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Geary TG. Nonpeptide ligands for peptidergic G protein-coupled receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 692:10-26. [PMID: 21189672 DOI: 10.1007/978-1-4419-6902-6_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Neuropeptides play essential roles in many physiological systems in vertebrates and invertebrates. Peptides per se are difficult to use as therapeutic agents, as they are generally very unstable in biological fluid environments and cross biological membranes poorly. Recognition that nonpeptide ligands for peptide receptors have clinical utility came from the discovery that opiates (such as morphine) act by binding to G protein-coupled receptors (GPCRs) for which the endogenous ligands are a family of neuropeptides (enkephalins and endorphins). Basic research has revealed a very large number of distinct neuropeptides that influence virtually every aspect of mammalian physiology and considerable effort has been expended in the pursuit of new drugs that act through peptidergic signaling systems. Although useful drugs have been found to affect various aspects ofneuropeptide biology, most work has been devoted to the discovery of nonpeptide ligands that act as agonists or antagonists at peptidergic GPCRs. Similar opportunities are apparent for the discovery of nonpeptide ligands that act on invertebrate GPCRs. A consideration of the knowledge gained from the process as conducted for mammalian peptidergic systems can inform and illuminate promising strategies for the discovery of new drugs for the treatment and control of pests and parasites.
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Affiliation(s)
- Timothy G Geary
- Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC, Canada.
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González N, Nakagawa T, Mantey SA, Sancho V, Uehara H, Katsuno T, Jensen RT. Molecular basis for the selectivity of the mammalian bombesin peptide, neuromedin B, for its receptor. J Pharmacol Exp Ther 2009; 331:265-76. [PMID: 19628633 DOI: 10.1124/jpet.109.154245] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mammalian bombesin (Bn) peptides, neuromedin B (NMB) and gastrin-releasing peptide (GRP), have widespread actions in many tissues, and their effects are mediated by two closely related G-protein-coupled receptors, the NMBR and GRPR. Little is known about the structural determinants of NMBR selectivity for NMB, in contrast to GRP selectivity for the GRPR, which has been extensively studied. To provide insight, chimeric NMBR-GRPR loss-of-affinity and gain-of-affinity mutants were made, as well as NH(2)-terminally truncated NMBR and point mutants using site-directed mutagenesis. Receptors were expressed in Balb-3T3-cells or CHOP cells, and affinities were determined. NMB had 115-fold greater affinity for NMBR than GRPR. Receptor-chimeric studies showed that NMBR selectivity for NMB was primarily determined by differences in the third extracellular (EC3) regions of GRPR-NMBR and adjacent upper-transmembrane-5 (TM5) region. In this region, 24 NMB gain-of-affinity GRPR mutants or NMBR loss-of-affinity point/combination mutants were made. Three gain-of-affinity mutant GRPRs [[A198I] (EC3), [H202Q] (EC3), [S215I] (upper TM5)] had increased NMB affinity (2.4-21-fold), and these results were confirmed with NMBR loss-of-affinity mutants [I199A,Q203H,I215S-NMBR]. The combination mutant [A198I,S215]GRPR had the greatest effect causing a complete NMB gain-of-affinity. The importance of differences at position 199NMBR or 203NMBR was studied by substituting amino acids with various properties. Our results show that NMBR selectivity for NMB is due to differences in the EC3 of NMBR-GRPR and the adjacent upper-TM5 region. Within these regions, isoleucines in NMBR [position 199 (EC3)] (instead of A198GRPR) and in 215NMBR (TM5) (instead of S214GRPR), as well as Q203NMBR (instead of H202GRPR) are responsible for high NMB-affinity/selectivity of NMBR. The effect at position 199 is primarily due to differences in hydrophobicity of the substitution, whereas steric factors and charge of the substitution at position 203 were important determinants of NMB selectivity.
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Affiliation(s)
- Nieves González
- Digestive Diseases Branch, NIDDK, NIH, Bethesda, MD 20892-1804, USA
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Javdan P, Figini M, Ricciardolo FLM, Geppetti P. Nedocromil sodium and sodium cromoglycate inhibit plasma extravasation in the guinea-pig conjunctiva. Ocul Immunol Inflamm 2009; 3:37-44. [DOI: 10.3109/09273949509057809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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17
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Leffler A, Ahlstedt I, Engberg S, Svensson A, Billger M, Oberg L, Bjursell MK, Lindström E, von Mentzer B. Characterization of species-related differences in the pharmacology of tachykinin NK receptors 1, 2 and 3. Biochem Pharmacol 2009; 77:1522-30. [PMID: 19426690 DOI: 10.1016/j.bcp.2009.01.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 01/27/2009] [Accepted: 01/30/2009] [Indexed: 11/28/2022]
Abstract
Tachykinin NK receptors (NKRs) differ to a large degree among species with respect to their affinities for small molecule antagonists. The aims of the present study were to clone NKRs from gerbil (NK2R and NK3R) and dog (NK1R, NK2R and NK3R) in which the sequence was previously unknown and to investigate the potency of several NKR antagonists at all known human, dog, gerbil and rat NKRs. The NKR protein coding sequences were cloned and expressed in CHO cells. The inhibitory concentrations of selective and non-selective NKR antagonists were determined by inhibition of agonist-induced mobilization of intracellular Ca2+. Receptor homology models were constructed based on the rhodopsin crystal structure to investigate and identify the antagonist binding sites and interaction points in the transmembrane (TM) regions of the NKRs. Data collected using the cloned dog NK1R confirmed that the dog NK1R displays similar pharmacology as the human and the gerbil NK1R, but differs greatly from the mouse and the rat NK1R. Despite species-related amino acid (AA) differences located close to the antagonist binding pocket of the NK2R, they did not affect the potency of the antagonists ZD6021 and saredutant. Two AA differences located close to the antagonist binding site of NK3R likely influence the NK3R antagonist potency, explaining the 3-10-fold decrease in potency observed for the rat NK3R. For the first time, detailed pharmacological experiments in vitro with cloned NKRs demonstrate that not only human, but also dog and gerbil NKR displays similar antagonist pharmacology while rat diverges significantly with respect to NK1R and NK3R.
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Affiliation(s)
- Agnes Leffler
- Department of Bioscience, AstraZeneca R&D, Mölndal, Sweden
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18
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Brocco M, Dekeyne A, Mannoury la Cour C, Touzard M, Girardon S, Veiga S, de Nanteuil G, deJong TR, Olivier B, Millan MJ. Cellular and behavioural profile of the novel, selective neurokinin1 receptor antagonist, vestipitant: a comparison to other agents. Eur Neuropsychopharmacol 2008; 18:729-50. [PMID: 18657401 DOI: 10.1016/j.euroneuro.2008.06.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 05/06/2008] [Accepted: 06/12/2008] [Indexed: 10/21/2022]
Abstract
This study characterized the novel neurokinin (NK)(1) antagonist, vestipitant, under clinical evaluation for treatment of anxiety and depression. Vestipitant possessed high affinity for human NK(1) receptors (pK(i), 9.4), and potently blocked Substance P-mediated phosphorylation of Extracellular-Regulated-Kinase. In vivo, it occupied central NK(1) receptors in gerbils (Inhibitory Dose(50), 0.11 mg/kg). At similar doses, it abrogated nociception elicited by formalin in gerbils, and blocked foot-tapping and locomotion elicited by the NK(1) agonist, GR73632, in gerbils and guinea pigs, respectively. Further, vestipitant attenuated fear-induced foot-tapping in gerbils, separation-induced distress-vocalizations in guinea pigs, marble-burying behaviour in mice, and displayed anxiolytic actions in Vogel conflict and fear-induced ultrasonic vocalization procedures in rats. These actions were mimicked by CP99,994, L733,060 and GR205,171 which acted stereoselectively vs its less active isomer, GR226,206. In conclusion, vestipitant is a potent NK(1) receptor antagonist: its actions support the utility of NK(1) receptor blockade in the alleviation of anxiety and, possibly, depression.
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Affiliation(s)
- Mauricette Brocco
- Psychopharmacology Department, Institut de Recherches Servier, Centre de Recherches de Croissy, 125 chemin de Ronde, Croissy/Seine, Paris, France
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19
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Ahlstedt I, Engberg S, Smith J, Perrey C, Moody A, Morten J, Lagerström-Fermér M, Drmota T, von Mentzer B, Påhlman I, Lindström E. Occurrence and pharmacological characterization of four human tachykinin NK2 receptor variants. Biochem Pharmacol 2008; 76:476-81. [DOI: 10.1016/j.bcp.2008.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 06/01/2008] [Accepted: 06/05/2008] [Indexed: 10/21/2022]
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20
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Fu CY, Zhao YL, Dong L, Chen Q, Ni JM, Wang R. In vivo characterization of the effects of human hemokinin-1 and human hemokinin-1(4-11), mammalian tachykinin peptides, on the modulation of pain in mice. Brain Behav Immun 2008; 22:850-60. [PMID: 18262387 DOI: 10.1016/j.bbi.2007.12.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 12/09/2007] [Accepted: 12/22/2007] [Indexed: 11/18/2022] Open
Abstract
Human hemokinin-1 (h HK-1) and its truncated form h HK-1(4-11) are mammalian tachykinin peptides encoded by the recently identified TAC4 gene in human, and the biological functions of these peptides have not been well investigated. In the present study, an attempt has been made to investigate the effects and mechanisms of action of h HK-1 and h HK-1(4-11) in pain modulation at the supraspinal level in mice using the tail immersion test. Intracerebroventricular (i.c.v.) administration of h HK-1 (0.3, 1, 3 and 6 nmol/mouse) produced a dose- and time-related antinociceptive effect. This effect was significantly antagonized by the NK(1) receptor antagonist SR140333, but not by the NK(2) receptor antagonist SR48968, indicating that the analgesic effect induced by i.c.v. h HK-1 is mediated through the activation of NK(1) receptors. Interestingly, naloxone, beta-funaltrexamine and naloxonazine, but not naltrindole and nor-binaltorphimine, could also block the analgesic effect markedly, suggesting that this effect is related to descending mu opioidergic neurons (primary mu(1) subtype). Human HK-1(4-11) could also induce a dose- and time-dependent analgesic effect after i.c.v. administration, however, the potency of analgesia was less than h HK-1. Surprisingly, SR140333 could not modify this analgesic effect, suggesting that this effect is not mediated through the NK(1) receptors like h HK-1. SR48968 could modestly enhance the analgesic effect induced by h HK-1(4-11), indicating that a small amount of h HK-1(4-11) may bind to NK(2) receptors. Furthermore, none of the opioid receptor (OR) antagonists could markedly block the analgesia of h HK-1(4-11), suggesting that the analgesic effect is not mediated through the descending opioidergic neurons. Blocking of delta ORs significantly enhanced the analgesia, indicating that delta OR is a negatively modulatory factor in the analgesic effect of h HK-1(4-11). It is striking that bicuculline (a competitive antagonist at GABA(A) receptors) effectively blocked the analgesia induced by h HK-1(4-11), suggesting that this analgesic effect is mediated through the descending inhibitory GABAergic neurons. The novel mechanism involved in the analgesic effect of h HK-1(4-11), which is different from that of h HK-1, may pave the way for a new strategy for the investigation and control of pain.
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Affiliation(s)
- Cai Y Fu
- State Key Laboratory of Chinese Medicine and Molecular Pharmacology, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong
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Griffante C, Carletti R, Andreetta F, Corsi M. [3H]GR205171 displays similar NK1 receptor binding profile in gerbil and human brain. Br J Pharmacol 2007; 148:39-45. [PMID: 16501582 PMCID: PMC1617048 DOI: 10.1038/sj.bjp.0706697] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1 In this study, [(3)H]GR205171 (3(S)-(2-methoxy-5-(5-trifluoromethyltetrazol-1-yl)-phenylmethylamino)-2(S)-phenylpiperidine), a potent and selective NK1 receptor antagonist, was characterised in autoradiographic studies in gerbil brain and in binding experiments on homogenates from gerbil and human brain cortex and striatum. 2 In autoradiographic studies in gerbil brain, highest levels of [(3)H]GR205171 binding sites were observed in caudate putamen, nucleus accumbens, medial and cortical nuclei of the amygdala and intermediate levels were detected in the hypothalamus, basolateral amygdala, septum, and cortex. 3 Saturation experiments in homogenates of brain striatum from gerbil showed that [(3)H]GR205171 binds to a single receptor population with a pK(d) value of 10.8+/-0.2 and a B(max) value of 607+/-40 fmol mg(-1). A lower number of NK1 receptor sites was found in cortex, where a B(max) of 94+/-6 fmol mg(-1) protein was obtained. Saturation experiments performed on homogenates from brain striatum of two human subjects and brain cortex of three human subjects showed that [(3)H]GR205171 binds with pK(d) values not different from gerbil and B(max) values ranging from 318+/-51 to 432+/-27 fmol mg(-1) protein in striatum and from 59+/-1 to 74+/-21 fmol mg(-1) protein in cortex. The natural ligand [(3)H]Substance P (SP) bound with sub-nanomolar affinity to 15 and 6% sites compared to [(3)H]GR205171 in gerbil and human striatum, respectively. 4 In competition binding experiments, GR205171 and the NK1 receptor antagonists aprepitant (MK-869), L-733,060 and NKP-608 bound with similar pK(i) values in gerbil and human striatum, irrespective of the use of [(3)H]GR205171 or [(3)H]SP as radioligand. The following rank order was found in terms of pK(i) values: GR205171>aprepitant> or =L-733,060>NKP-608. In homologous displacement experiments in gerbil and human striatum, SP showed nanomolar affinity, whereas in [(3)H]GR205171 competition experiments SP bound with pIC(50) values in the micromolar range and Hill slopes significantly lower than one. 5 It is concluded that the similarities of [(3)H]GR205171 binding characteristics and pharmacology between gerbil and human in cortex and striatum support the use of gerbil in preclinical models to study the effects of NK1 receptor antagonists in the central nervous system.
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Affiliation(s)
- Cristiana Griffante
- Psychiatry Centre of Excellence for Drug Discovery, GlaxoSmithKline Group, Medicines Research Centre, 37135 Verona, Italy.
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Losco PE, Leach MW, Sinha D, Davis P, Schmahai TJ, Nomier A, Kakkar T, Reyderman L, Lynch ME. Administration of an antagonist of neurokinin receptors 1, 2, and 3 results in reproductive tract changes in beagle dogs, but not rats. Toxicol Pathol 2007; 35:310-22. [PMID: 17366326 DOI: 10.1080/01926230701198766] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
SCH 206272, an antagonist of neurokinin receptors 1, 2, and 3, was administered orally by gavage for 1 month to 8- to 10-month-old dogs at doses of 0, 15, 30, or 60 mg/kg, and to 6-week-old rats at doses of 0, 30, 100, or 300 mg/kg. The most important changes occurred in the reproductive tract of the dogs at all doses. Absolute and relative group mean organ weights for the testes, prostate gland, epididymides, ovaries, and uterus were 33-86% lower than concurrent controls in groups receiving SCH 206272. Organ weight changes were not dose-related. Microscopic changes that correlated with the organ weight changes occurred in all groups receiving SCH 206272. For males, they included minimal to severe atrophy of the testes, epididymides, and prostate gland. In addition, the epididymides exhibited severe oligospermia or aspermia, minimal epithelial apoptosis and mild epithelial vacuolation. In female dogs, the ovaries and uteri appeared immature. Microscopic changes were similar in incidence and severity in dogs receiving 30 or 60 mg/kg, but were slightly less in dogs receiving 15 mg/kg. In contrast, similar findings were not observed in the reproductive tract of male or female rats, despite overlapping systemic, hypothalamic, and pituitary gland concentrations of SCH 206272.
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Al-Fulaij MA, Ren Y, Beinborn M, Kopin AS. Identification of amino acid determinants of dopamine 2 receptor synthetic agonist function. J Pharmacol Exp Ther 2007; 321:298-307. [PMID: 17204745 DOI: 10.1124/jpet.106.116384] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The human dopamine 2 receptor (hD2R) modulates locomotor activity, hormone secretion, and neuropsychiatric function. Current knowledge of the hD2R structure is in large part derived from mutagenesis studies and molecular pharmacologic analysis together with homology modeling using bovine rhodopsin as a template. In this study, we utilized comparison of the Drosophila D2-like receptor (DD2R) with the hD2R as a novel approach for identifying candidate amino acids that are determinants of ligand potency and/or efficacy. We focused our studies on four dopaminergic ligands that are used in the treatment of Parkinson's disease: bromocriptine, pergolide, piribedil, and ropinirole. All four ligands are potent agonists at the wild-type hD2R, whereas only bromocriptine shows comparable function at the DD2R. We performed site-directed mutagenesis to replace hD2R amino acids (modeled to project into the ligand binding pocket) with corresponding fly residues, and vice versa. Substitution of three amino acids in the hD2R with the homologous DD2R residues (V91A, C118S, and L170I) led to a pronounced loss of pergolide potency and efficacy. A converse triple amino acid substitution of human residues into the fly receptor (DD2R-A133V/S160C/I211L) markedly enhanced pergolide efficacy and potency at the mutant DD2R. The same substitutions also converted piribedil and ropinirole, which lacked appreciable activity on the DD2R, to partial agonists. These findings show the important role of these three residues in drug-receptor interactions. Our study illustrates that comparison of a mammalian receptor with an invertebrate homolog complements previously described strategies for defining G protein-coupled receptor structure-function relationships.
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Affiliation(s)
- Munya A Al-Fulaij
- Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
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25
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Haneda E, Higuchi M, Maeda J, Inaji M, Okauchi T, Ando K, Obayashi S, Nagai Y, Narazaki M, Ikehira H, Nakao R, Zhang MR, Suzuki K, Suzuki H, Suhara T. In vivo mapping of substance P receptors in brains of laboratory animals by high-resolution imaging systems. Synapse 2007; 61:205-15. [PMID: 17230554 DOI: 10.1002/syn.20363] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neurotransmission mediated by substance P (SP) and NK(1) receptor has been implicated in the pathophysiology of analgesia, emesis and diverse neuropsychiatric conditions including depression and anxiety disorder. Several lines of clinical trials using NK(1) receptor antagonists have been conducted to date, and the efficiency of preclinical assessments for proof of concept and dose optimization could be greatly increased by configuring an in vivo analytical system that permits quantitative mapping of NK(1) receptors in the brains of small-size laboratory animals expressing "human-like" NK(1) receptors. Hence, we investigated the applicability of experimental animals, ranging from rodents to primates, to positron emission tomographic (PET) measurements with [(18)F]fluoroethyl-SPA-RQ, a modification of a recently established radioligand for NK(1) receptors. A pharmacokinetic assay could be performed for a rhesus monkey in an awake condition, which allows the circumvention of influences of anesthesia on SP neurotransmission. Coregistration of PET and magnetic resonance images acquired by small-animal-dedicated devices enabled detailed localization of NK(1) receptors in the gerbil and marmoset brains. The present study also revealed the potentials of SDZ NKT 343 as an antagonist for central NK(1) receptors. In conjunction with additional in vitro and ex vivo autoradiographic observations, our in vivo results have demonstrated a similarity in the binding pattern among the animals examined, justifying cross-species extrapolation of PET findings on the SP-NK(1) pathway.
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Affiliation(s)
- Eisuke Haneda
- Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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Nagano M, Saitow F, Haneda E, Konishi S, Hayashi M, Suzuki H. Distribution and pharmacological characterization of primate NK-1 and NK-3 tachykinin receptors in the central nervous system of the rhesus monkey. Br J Pharmacol 2006; 147:316-23. [PMID: 16331282 PMCID: PMC1751306 DOI: 10.1038/sj.bjp.0706561] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Much attention has focused on tachykinin receptors as therapeutic targets for neuropsychiatric disorders, although their expressional distributions in the primate central nervous system (CNS) remain unclear. We cloned the genes encoding the NK-1 and NK-3 tachykinin receptors (referred to as rmNK-1 and rmNK-3) from the rhesus monkey (Macaca mulatta) brain and examined their pharmacological profiles and regional distributions in the CNS. The deduced rmNK-1 amino-acid sequence differed by only two amino acids from the human NK-1 (hNK-1). The deduced rmNK-3 amino-acid sequence was two amino acids shorter than human NK-3 (hNK-3), with a seven-amino-acid difference in sequence. Ligand binding studies revealed that the affinity of rmNK-1 to substance P (SP) was comparable to that of hNK-1 in cell lines that expressed individual receptors stably. Nonpeptide antagonists had similar effects on the binding of rmNK-1 and hNK-1. Affinity of rmNK-3 for NKB was stronger than for SP and the IC50 value was comparable with that of hNK-3. Ca2+ imaging showed that activations of both rmNK-1 and rmNK-3 by specific ligands, SP and senktide, induced increased intracellular Ca2+ in cell lines that stably expressed individual primate tachykinin receptors. The amounts of rmNK-1 and rmNK-3 mRNAs were quantitatively determined in the monkey CNS. The expression of rmNK-1 was observed in all of the cortical and subcortical regions, including the hippocampus and the amygdala. The putamen contained the most NK-1 mRNA in the brain, with less rmNK-3 mRNA found in the cortex compared to rmNK-1 mRNA. In the monkey hippocampus and amygdala, rmNK-1 mRNA was present at markedly higher concentrations than rmNK-3 mRNA. The present results provide an insight into the distinct physiological nature and significance of the NK-1 and NK-3 tachykinin systems in the primate CNS. These findings are indispensable for establishing model systems in the search for a subtype-specific tachykinin receptor agonist and antagonist for the treatment of neuropsychiatric disorders.
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Affiliation(s)
- Masatoshi Nagano
- Department of Pharmacology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Fumihito Saitow
- Department of Pharmacology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Eisuke Haneda
- Department of Pharmacology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
| | - Shiro Konishi
- Waseda-Olympus Bioscience Research Institute, Waseda University, Singapore 138667, Singapore
| | - Motoharu Hayashi
- Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan
- Author for correspondence:
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Engberg S, Ahlstedt I, Leffler A, Lindström E, Kristensson E, Svensson A, Påhlman I, Johansson A, Drmota T, von Mentzer B. Molecular cloning, mutations and effects of NK1 receptor antagonists reveal the human-like pharmacology of gerbil NK1 receptors. Biochem Pharmacol 2006; 73:259-69. [PMID: 17097619 DOI: 10.1016/j.bcp.2006.09.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 09/13/2006] [Accepted: 09/28/2006] [Indexed: 10/24/2022]
Abstract
The present study investigates the pharmacology of the cloned neurokinin 1 receptor from the gerbil (gNK(1)R), a species claimed to have human-like NK(1)R (hNK(1)R) pharmacology. The amino acid sequence of NK(1)R was cloned. The hNK(1)R, rat NK(1)R (rNK(1)R), gNK(1)R and mutants of the gNK(1)R were expressed in CHO cells. The affinity and potency of NKR agonists and the NK(1)R antagonists CP99994 and RP67580 (NK(1)R-selective) and ZD6021 (NK1/2R) were assessed in vitro by monitoring [(3)H]-SarMet SP binding and substance P-evoked mobilization of intracellular Ca(2+). The gerbil foot tap (GFT) method was used to assess the potency of the antagonists in vivo. The gNK(1)R coding sequence displayed an overall 95% and 97% homology with hNK(1)R and rNK(1)R, respectively. The affinity of the NK(1)R-selective agonist (3)H-SarMet SP for human and gerbil NK(1)R was similar (2.0 and 3.1 nM) but lower for rNK(1)R (12.4 nM). The rank order potency of the agonists for NK(1)R was SP > or = ASMSP > or = NKA >>> pro7NKB in all species. The NK(1)R antagonists, ZD6021 and CP99994, had comparable affinity and potency for gerbil and human NK(1)R, but were 1000-fold less potent for rNK(1)R. In contrast, RP67580 had comparable affinity and potency for all three species. Mutations in positions 116 and 290 did not affect agonist potency at the gNK(1)R while the potency of the antagonists ZD6021 and CP99994 were markedly decreased (10-20-fold). It is concluded that gNK(1)R has similar antagonist pharmacology as the human-like orthologue and that species differences in antagonist function depend on key residues in the coding sequence and antagonist structure.
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Affiliation(s)
- Susanna Engberg
- AstraZeneca Research and Development, 431 83 Mölndal, Sweden
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Ebner K, Singewald N. The role of substance P in stress and anxiety responses. Amino Acids 2006; 31:251-72. [PMID: 16820980 DOI: 10.1007/s00726-006-0335-9] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Accepted: 02/21/2006] [Indexed: 12/18/2022]
Abstract
Substance P (SP) is one of the most abundant peptides in the central nervous system and has been implicated in a variety of physiological and pathophysiological processes including stress regulation, as well as affective and anxiety-related behaviour. Consistent with these functions, SP and its preferred neurokinin 1 (NK1) receptor has been found within brain areas known to be involved in the regulation of stress and anxiety responses. Aversive and stressful stimuli have been shown repeatedly to change SP brain tissue content, as well as NK1 receptor binding. More recently it has been demonstrated that emotional stressors increase SP efflux in specific limbic structures such as amygdala and septum and that the magnitude of this effect depends on the severity of the stressor. Depending on the brain area, an increase in intracerebral SP concentration (mimicked by SP microinjection) produces mainly anxiogenic-like responses in various behavioural tasks. Based on findings that SP transmission is stimulated under stressful or anxiety-provoking situations it was hypothesised that blockade of NK1 receptors may attenuate stress responses and exert anxiolytic-like effects. Preclinical and clinical studies have found evidence in favour of such an assumption. The status of this research is reviewed here.
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Affiliation(s)
- K Ebner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
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Gu HH, Wu X, Han DD. Conserved serine residues in serotonin transporter contribute to high-affinity cocaine binding. Biochem Biophys Res Commun 2006; 343:1179-85. [PMID: 16580636 DOI: 10.1016/j.bbrc.2006.03.096] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 03/16/2006] [Indexed: 10/24/2022]
Abstract
Serotonin transporter (SERT) is one of the key protein targets of cocaine. Despite intensive studies, it is not clear where cocaine binds to its targets and what residues are involved in cocaine binding. We have cloned the serotonin transporter from silkworm (Bombyx mori, bmSERT). When expressed in cultured cells, bmSERT is over 20-fold less sensitive to cocaine than Drosophila melanogaster SERT (dmSERT). We performed species-scanning mutagenesis using bmSERT and dmSERT. There are two adjacent threonine residues in transmembrane domain 12 of bmSERT where the corresponding residues are two serines in dmSERT and in all known mammalian monoamine transporters. Replacing the serine residues with threonines in dmSERT reduces cocaine sensitivity; while switching the two threonine residues in bmSERT to serines increased cocaine sensitivity. Mutations at the corresponding residues in dopamine transporter also changed cocaine affinity. Our results suggest that the conserved serine residues in SERT contribute to high-affinity cocaine binding.
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Affiliation(s)
- Howard H Gu
- Department of Pharmacology, The Ohio State University College of Medicine, 333 West 10th Avenue, Columbus, OH 43210, USA.
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Faussone-Pellegrini MS. Relationships between neurokinin receptor-expressing interstitial cells of Cajal and tachykininergic nerves in the gut. J Cell Mol Med 2006; 10:20-32. [PMID: 16563219 PMCID: PMC3933099 DOI: 10.1111/j.1582-4934.2006.tb00288.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 02/10/2006] [Indexed: 01/25/2023] Open
Abstract
The so-called interstitial cells of Cajal (ICC) are distributed throughout the muscle coat of the alimentary tract with characteristic intramural location and species-variations in structure and staining. Several ICC sub-types have been identified: ICC-DMP, ICC-MP, ICC-IM, ICC-SM. Gut motility is regulated by ICC and each sub-type is responsible for the electrical activities typical of each gut region and/or muscle layer. The interstitial position of the ICC between nerve endings and smooth muscle cells has been extensively considered. Some of these nerve endings contain tachykinins. Three distinct tachykinin receptors (NK1r, NK2r and NK3r) have been demonstrated by molecular biology. Each of them binds with different affinities to a series of tachykinins (SP, NKA and NKB). In the ileum, SP-immunoreactive (SP-IR) nerve fibers form a rich plexus at the deep muscular plexus (DMP), distributed around SP-negative cells, and ICC-DMP intensely express the SP-preferred receptor NK1r; conversely a faint NK1r-IR is detected on the ICC-MP and mainly after receptor internalization was induced by agonists. ICC-IM are never stained in laboratory mammals, while those of the human antrum are NK1r- IR. RT-PCR conducted on isolated ileal ICC-MP and gastric ICC-IM showed that these cells express NK1r and NK3r. Colonic ICC, except those in humans, do not express NK1r-IR, at least in resting conditions. Outside the gut, NK1r-IR cells were seen in the arterial wall and exocrine pancreas. In the mouse gut only, NK1r-IR is present in non-neuronal cells located within the intestinal villi, so-called myoid cells, which are c-kit-negative and alpha-smooth muscle actin-positive. Immunohistochemistry and functional studies confirmed that ICC receive input from SP-IR terminals, with differences between ICC sub-types. In the rat, very early after birth, NK1r is expressed by the ICC-DMP and SP by the related nerve varicosities. Studies on pathological conditions are few and those on mutant strains practically absent. It has only been reported that in the inflamed ileum of rats the NK1r-IR ICC-DMP disappear and that at the peak of inflammatory conditions ICC-MP are NK1r-IR. In the ileum of mice with a mutation in the W locus, ICC-DMP were seen to express c-kit-IR but not NK1-IR, and SP-IR innervation seems unchanged. In summary, there are distinct ICC populations, each of them under a different tachykininergic control and, likely, having different functions. Further studies are recommended at the aim of understanding ICC involvement in modulating/transmitting tachykininergic inputs.
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Affiliation(s)
- Maria-Simonetta Faussone-Pellegrini
- Department of Anatomy, Histology and Forensic Medicine, Section of Histology, University of Florence, Viale G. Pieraccini, 6, 50134 Florence, Italy.
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Yamano K, Inoue M, Masaki S, Saki M, Ichimura M, Satoh M. Generation of adenosine A3 receptor functionally humanized mice for the evaluation of the human antagonists. Biochem Pharmacol 2005; 71:294-306. [PMID: 16300745 DOI: 10.1016/j.bcp.2005.10.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 10/17/2005] [Accepted: 10/17/2005] [Indexed: 11/26/2022]
Abstract
Although the adenosine A(3) receptor (A3AR), which is a G(i/o) protein-coupled receptor, has attracted considerable interest as a potential target for drugs against asthma or inflammation, the in vivo evaluation of the antagonists using rodents in the first step of drug development has been hampered by the lack of highly potent antagonists for the rodent A3AR. To evaluate the pharmacological effects of human A3AR antagonists in mice, we previously generated A3AR-humanized mice, in which the mouse A3AR gene was replaced by its human counterpart. However, the human A3AR did not lead to the phosphoinositide 3-kinase (PI3K) gamma-signaling pathway such as IgE/antigen-dependent mast cell degranulation, probably due to the uncoupling of the mouse G(i/o) protein(s). To overcome the uncoupling, we here generated A3AR functionally humanized mice by replacing the mouse A3AR gene with a human/mouse chimeric A3AR sequence in which whole intracellular regions of the human A3AR were substituted for the corresponding regions of the mouse A3AR. The chimeric A3AR led to intracellular Ca(2+) elevation and activation of the PI3Kgamma-signaling pathway, which are equivalent to the actions induced by A3AR in wild-type mice. The human A3AR antagonist had the same binding affinities for the chimeric A3AR as the human A3AR and completely antagonized this potentiation. This is the first direct evidence that the uncoupling of mouse G protein(s) to the human A3AR is due to a sequence difference in the intracellular regions of A3AR. The A3AR functionally humanized mice can be widely employed for pharmacological evaluations of the human A3AR antagonists.
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Affiliation(s)
- Kazuya Yamano
- Tokyo Research Laboratories, Kyowa Hakko Kogyo Co. Ltd., 3-6-6 Asahi-machi, Machida-shi, Tokyo 194-8533, Japan
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Haskell CA, Horuk R, Liang M, Rosser M, Dunning L, Islam I, Kremer L, Gutiérrez J, Marquez G, Martinez-A C, Biscone MJ, Doms RW, Ribeiro S. Identification and Characterization of a Potent, Selective Nonpeptide Agonist of the CC Chemokine Receptor CCR8. Mol Pharmacol 2005; 69:309-16. [PMID: 16221874 DOI: 10.1124/mol.105.014779] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we report the first example of a nonpeptide chemokine receptor agonist, 2-{2-[4-(3-phenoxybenzyl)piperazin-1-yl]ethoxy}ethanol (ZK 756326), for the CC chemokine receptor CCR8. ZK 756326 inhibited the binding of the CCR8 ligand I-309 (CCL1), with an IC(50) value of 1.8 muM. Furthermore, ZK 756326 was a full agonist of CCR8, dose-responsively eliciting an increase in intracellular calcium and cross-desensitizing the response of the receptor to CCL1. In addition, ZK 756326 stimulated extracellular acidification in cells expressing human CCR8. The ability of ZK 756326 to induce a response was receptor-specific and mediated through Galpha(i), because it could be blocked by treatment with pertussis toxin. The CCR8 agonist activated cells expressing murine CCR8, eliciting their chemotaxis and inducing phosphorylation of extracellular signal-regulated kinase ERK1/2. Like CCL1, ZK 756326 inhibited human immunodeficiency virus (HIV) fusion of cells expressing CD4 and CCR8. Finally, unlike mCCL1, ZK 756326 bound to and activated a form of mCCR8 that was mutated to eliminate O-linked sulfation at tyrosines 14 and 15. Therefore, ZK 756326 is most probably not binding in the same manner as CCL1 but can activate the switch mechanism involved in transducing signaling events. In summary, we have identified a nonpeptide agonist of CCR8. This compound may be useful in evaluating the physiological role of CCR8 in HIV infection, as well as in the general study of CCR8 biology without the constraints inherent to the use of protein agonists such as its natural ligand.
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Langer I, Tikhonova IG, Travers MA, Archer-Lahlou E, Escrieut C, Maigret B, Fourmy D. Evidence That Interspecies Polymorphism in the Human and Rat Cholecystokinin Receptor-2 Affects Structure of the Binding Site for the Endogenous Agonist Cholecystokinin. J Biol Chem 2005; 280:22198-204. [PMID: 15817487 DOI: 10.1074/jbc.m501786200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cholecystokinin (CCK) receptor-2 exerts very important central and peripheral functions by binding the neuropeptides cholecystokinin or gastrin. Because this receptor is a potential therapeutic target, great interest has been devoted to the identification of efficient antagonists. However, interspecies genetic polymorphism that does not alter cholecystokinin-induced signaling was shown to markedly affect activity of synthetic ligands. In this context, precise structural study of the agonist binding site on the human cholecystokinin receptor-2 is a prerequisite to elucidating the molecular basis for its activation and to optimizing properties of synthetic ligands. In this study, using site-directed mutagenesis and molecular modeling, we delineated the binding site for CCK on the human cholecystokinin receptor-2 by mutating amino acids corresponding to that of the rat homolog. By doing so, we demonstrated that, although resembling that of rat homolog, the human cholecystokinin receptor-2 binding site also displays important distinct structural features that were demonstrated by susceptibility to several point mutations (F120A, Y189A, H207A). Furthermore, docking of CCK in the human and rat cholecystokinin receptor-2, followed by dynamic simulations, allowed us to propose a plausible structural explanation of the experimentally observed difference between rat and human cholecystokinin-2 receptors.
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Affiliation(s)
- Ingrid Langer
- Institut National de la Santé et de la Recherche Médicale (INSERM), Institut Louis Bugnard, CHU Rangueil, 31432 Toulouse Cedex 4, France
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Duffy RA. Potential therapeutic targets for neurokinin-1 receptor antagonists. Expert Opin Emerg Drugs 2005. [DOI: 10.1517/14728214.9.1.9] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Shacham S, Marantz Y, Bar-Haim S, Kalid O, Warshaviak D, Avisar N, Inbal B, Heifetz A, Fichman M, Topf M, Naor Z, Noiman S, Becker OM. PREDICT modeling and in-silico screening for G-protein coupled receptors. Proteins 2005; 57:51-86. [PMID: 15326594 DOI: 10.1002/prot.20195] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
G-protein coupled receptors (GPCRs) are a major group of drug targets for which only one x-ray structure is known (the nondrugable rhodopsin), limiting the application of structure-based drug discovery to GPCRs. In this paper we present the details of PREDICT, a new algorithmic approach for modeling the 3D structure of GPCRs without relying on homology to rhodopsin. PREDICT, which focuses on the transmembrane domain of GPCRs, starts from the primary sequence of the receptor, simultaneously optimizing multiple 'decoy' conformations of the protein in order to find its most stable structure, culminating in a virtual receptor-ligand complex. In this paper we present a comprehensive analysis of three PREDICT models for the dopamine D2, neurokinin NK1, and neuropeptide Y Y1 receptors. A shorter discussion of the CCR3 receptor model is also included. All models were found to be in good agreement with a large body of experimental data. The quality of the PREDICT models, at least for drug discovery purposes, was evaluated by their successful utilization in in-silico screening. Virtual screening using all three PREDICT models yielded enrichment factors 9-fold to 44-fold better than random screening. Namely, the PREDICT models can be used to identify active small-molecule ligands embedded in large compound libraries with an efficiency comparable to that obtained using crystal structures for non-GPCR targets.
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Gobbi G. Serotonin Firing Activity as a Marker for Mood Disorders: Lessons from Knockout Mice. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 65:249-72. [PMID: 16140059 DOI: 10.1016/s0074-7742(04)65009-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- Gabriella Gobbi
- Department of Psychiatry, McGill University, Montréal, Québec, Canada H3A 1A1
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Abstract
Tachykinins play an important role as peptide modulators in the CNS. Based on the concentration and distribution of the peptides and their receptors, substance P (SP) and its cognate receptor neurokinin 1 (NK1R) seem to play a particularly important role in higher brain functions. They are expressed at high levels in the limbic system, which is the neural basis of emotional responses. Three different lines of evidence from physiological studies support such a role of SP in the regulation of emotionality: (1) stress is often associated with elevated level of SP in animals and humans; (2) systematic and local injections of SP influence anxiety levels in a dose-dependent and site-specific manner; (3) NK1 receptor antagonists show anxiolytic effects in different animal models of anxiety. Although these studies point to the NK1 receptor as a promising target for the pharmacotherapy of anxiety disorders, high affinity antagonists for the human receptors could not be studied in rats or mice due to species differences in the antagonist binding sites. However, studies on anxiety and depression-related behaviors have now been performed in mouse mutants deficient in NK1 receptor or SP and NKA. These genetic studies have shown that anxiety and depression-related phenotypes are profoundly affected by the tachykinin system. For example, NK1R-deficient mice seem to be less prone depression-related behaviors in models of depression, and one study also provided evidence for reduced anxiety levels. Mice deficient in SP and NKA behaved similarly as the NK1R knockouts. In animal models of anxiety they performed like wildtype mice treated with anxiolytic drugs. In behavioral paradigms related to depression they behaved like wildtype animals treated with antidepressants. In summary, the genetic studies clearly show that the SP/NK1 system plays an important role in the modulation of emotional behaviors.
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Affiliation(s)
- A Bilkei-Gorzo
- Laboratory of Molecular Neurobiology, Department of Psychiatry, University of Bonn, Siegmund-Freund-Strasse 25, 53105 Bonn, Germany
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Randolph GP, Simon JS, Arreaza MG, Qiu P, Lachowicz JE, Duffy RA. Identification of single-nucleotide polymorphisms of the human neurokinin 1 receptor gene and pharmacological characterization of a Y192H variant. THE PHARMACOGENOMICS JOURNAL 2004; 4:394-402. [PMID: 15452552 DOI: 10.1038/sj.tpj.6500276] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurokinin receptors in the central nervous system are involved in the neural circuitry of anxiety, depression and emesis. This has led to the development of nonpeptidic NK1 receptor antagonists as therapeutic agents. Clinical trials have shown that NK1 receptor antagonists have efficacy in chemotherapy-induced emesis and depression. Sequence polymorphisms can potentially influence the efficacy of drugs in patient populations and are an important consideration in the drug development process. To identify DNA sequence variants in the NK1 receptor, comparative DNA sequencing was performed on a population of 93 individuals. In total, 19 single-nucleotide polymorphisms (SNPs) were identified with one SNP (g.78351T>C) resulting in a tyrosine to histidine substitution at residue 192 (Y192H). The Y192H variant was expressed using site-directed mutagenesis and was characterized with respect to affinity, receptor kinetics, functional calcium response and receptor internalization. In all cases the Y192H variant was found to display properties similar to those of the wild-type receptor.
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Affiliation(s)
- G P Randolph
- CV/CNS Biological Research and Discovery Technologies, Schering-Plough Research Institute, Kenilworth, NJ 07033, USA
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Abstract
Several aspects of our 25 year adventure in the field of tachykinins will be successively described. They concern: substance P (SP) synthesis and release in the basal ganglia, the identification and pharmacological characterization of central tachykinin NK(1), NK(2) and NK(3) binding sites and their topographical distribution, the description of some new biological tests for corresponding receptors, the identification of tachykinin NK(1) receptor subtypes or conformers sensitive to all endogenous tachykinins (substance P, neurokinin A (NKA), neurokinin B (NKB), neuropeptide gamma (NP gamma) and neuropeptide K (NPK)) and finally, the functional involvement of these receptors and their subtypes in tachykinin-induced regulations of dopamine and acetylcholine release in the striatum.
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Affiliation(s)
- Jean-Claude Beaujouan
- Collège de France, INSERM U 114, Chaire de Neuropharmacologie, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.
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Rupniak NMJ, Carlson EJ, Shepheard S, Bentley G, Williams AR, Hill A, Swain C, Mills SG, Di Salvo J, Kilburn R, Cascieri MA, Kurtz MM, Tsao KL, Gould SL, Chicchi GG. Comparison of the functional blockade of rat substance P (NK1) receptors by GR205171, RP67580, SR140333 and NKP-608. Neuropharmacology 2003; 45:231-41. [PMID: 12842129 DOI: 10.1016/s0028-3908(03)00157-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Extensive screening of compound libraries was undertaken to identify compounds with high affinity for the rat NK(1) receptor based on inhibition of [(125)I]-substance P binding. RP67580, SR140333, NKP-608 and GR205171 were selected as compounds of interest, with cloned rat NK(1) receptor binding K(i) values of 0.15-1.9 nM. Despite their high binding affinity, NKP-608 and GR205171 exhibited only a moderate functional antagonism of substance P-induced inositol-1-phosphate accumulation and acidification rate at 1 microM using cloned or native rat NK(1) receptors in vitro. The ability of the compounds to penetrate the CNS was determined by inhibition of NK(1) agonist-induced behaviours in gerbils and rats. GR205171 and NKP-608 potently inhibited GR73632-induced foot drumming in gerbils (ID(50) 0.04 and 0.2 mg/kg i.v., respectively). In contrast, RP67580 and SR140333 were poorly brain penetrant in gerbils (no inhibition at 10 mg/kg i.v.) and were not examined further in vivo. In rats, only high doses of GR205171 (10 or 30 mg/kg s.c.) inhibited NK(1) agonist-induced sniffing and hypertension, whilst NKP-608 (1 or 10 mg/kg i.p.) was without effect. GR205171 (3-30 mg/kg s.c.) caused only partial inhibition of separation-induced vocalisations in rat pups, a response that is known to be NK(1) receptor mediated in other species. These observations demonstrate the shortcomings of currently available NK(1) receptor antagonists for rat psychopharmacology assays.
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Affiliation(s)
- Nadia M J Rupniak
- Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, UK.
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Duffy RA, Hedrick JA, Randolph G, Morgan CA, Cohen-Williams ME, Vassileva G, Lachowicz JE, Laverty M, Maguire M, Shan LS, Gustafson E, Varty GB. Centrally administered hemokinin-1 (HK-1), a neurokinin NK1 receptor agonist, produces substance P-like behavioral effects in mice and gerbils. Neuropharmacology 2003; 45:242-50. [PMID: 12842130 DOI: 10.1016/s0028-3908(03)00150-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hemokinin-1 (HK-1) is a recently described mouse tachykinin peptide whose biological functions are not fully understood. To date, a unique receptor for HK-1 has not been identified. Recent studies suggest HK-1 may have a role in immunological functions, but there has been little characterization of HK-1's effects in the central nervous system (CNS). In the present studies, we confirm that HK-1 is an endogenous agonist at all of the known tachykinin receptors, and is selective for the NK1 receptor over the NK2 and NK3 subtypes. CHO cells transfected with the human NK1 receptor released intracellular calcium in response to HK-1. In addition, HK-1 competed with substance P (SP) for binding to mouse NK1 and human NK1 receptors. In vivo central administration of HK-1 to gerbils and mice induced foot-tapping and scratching behaviors, respectively, similar to those observed following central administration of SP or the NK1 receptor agonist, GR-73632. Furthermore, these behavioral effects were blocked by the selective NK1 receptor antagonist, MK-869. Finally, a comprehensive expression analysis of HK-1 demonstrated that HK-1 mRNA is much more broadly expressed than previously reported with expression observed in many brain regions. Together these data demonstrate that HK-1 is a functional agonist at NK1 receptors and suggest that HK-1 may function both centrally and peripherally.
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Affiliation(s)
- R A Duffy
- Schering-Plough Research Institute, Department of CNS Biological Research, 2051 Galloping Hill Road, Kenilworth, NJ 07033, USA.
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Lecci A, Maggi CA. Peripheral tachykinin receptors as potential therapeutic targets in visceral diseases. Expert Opin Ther Targets 2003; 7:343-62. [PMID: 12783571 DOI: 10.1517/14728222.7.3.343] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
More than 10 years of intensive preclinical investigation of selective tachykinin (TK) receptor antagonists has provided a rationale to the speculation that peripheral neurokinin (NK)-1, -2 and -3 receptors may be involved in the pathophysiology of various human diseases at the visceral level. In the airways, despite promising effects in animal models of asthma, pilot clinical trials with selective NK-1 or -2 receptor antagonists in asthmatics have been ambiguous, whereas the potential antitussive effects of NK-1, -2 or -3 antagonists have not yet been verified in humans. In the gastrointestinal (GI) tract, irritable bowel syndrome (IBS) and pancreatitis are appealing targets for peripherally-acting NK-1 and -2 antagonists, respectively. In the genito-urinary tract, NK-1 receptor antagonists could offer some protection against nephrotoxicity and cytotoxicity induced by chemotherapeutic agents, whereas NK-2 receptor antagonists appear to be promising new agents for the treatment of neurogenic bladder hyperreflexia. Finally, there is preclinical evidence for hypothesising an effect of NK-3 receptor antagonists on the cardiovascular disturbance that characterises pre-eclampsia. Other more speculative applications are also mentioned.
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Affiliation(s)
- Alessandro Lecci
- Pharmacology Department of Menarini Ricerche, via Rismondo 12/A, 50131 Florence, Italy.
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Hill R. NK1 Receptor Antagonists Potential Analgesics? Pain 2003. [DOI: 10.1201/9780203911259.ch41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Wu X, Gu HH. Cocaine affinity decreased by mutations of aromatic residue phenylalanine 105 in the transmembrane domain 2 of dopamine transporter. Mol Pharmacol 2003; 63:653-8. [PMID: 12606774 DOI: 10.1124/mol.63.3.653] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dopamine transporter (DAT) is a major target of cocaine, one of the most abused drugs. Major efforts have been focused on defining residues in DAT involved in cocaine binding. We have isolated the Drosophila melanogaster DAT (dDAT) cDNA, which is 10-fold less sensitive to cocaine than the mammalian DATs. Replacing transmembrane domain 2 (TM2) of mouse DAT (mDAT) with dDAT sequence reduced cocaine sensitivity. The reciprocal construct exhibited increased cocaine sensitivity. Switching residue 105 in TM2, a phenylalanine conserved in all mammalian DATs, to methionine, the corresponding residue in dDAT, resulted in a functional transporter with cocaine sensitivity 4-fold lower. Replacing F105 with alanine, leucine, isoleucine, serine, threonine, asparagine, or glutamine resulted in transporters with low transport activity. In contrast, changing F105 to the other aromatic residues tyrosine or tryptophan retained more than 75% transport activity and high cocaine sensitivity. Most significantly, the reciprocal construct, switching the methionine in dDAT at the corresponding residue to phenylalanine, increased cocaine sensitivity 3-fold. Finally, the mDAT mutant with a cysteine at this position had normal transport activity but exhibited cocaine sensitivity that was 15-fold lower. These results suggest that F105 in mDAT contributes to high-affinity cocaine binding. The functional cocaine-insensitive mutants provide tools for the study of the mechanism of cocaine addiction.
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Affiliation(s)
- Xiaohong Wu
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066, USA
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Sandhu SK, Ross LS, Gill SS. A cocaine insensitive chimeric insect serotonin transporter reveals domains critical for cocaine interaction. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3934-44. [PMID: 12180970 DOI: 10.1046/j.1432-1033.2002.03084.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serotonin transporters are key target sites for clinical drugs and psychostimulants, such as fluoxetine and cocaine. Molecular cloning of a serotonin transporter from the central nervous system of the insect Manduca sexta enabled us to define domains that affect antagonist action, particularly cocaine. This insect serotonin transporter transiently expressed in CV-1 monkey kidney cells exhibits saturable, high affinity Na+ and Cl- dependent serotonin uptake, with estimated Km and Vmax values of 436 +/- 19 nm and 3.8 +/- 0.6 x 10-18 mol.cell.min-1, respectively. The Manduca high affinity Na+/Cl- dependent transporter shares 53% and 74% amino acid identity with the human and fruit fly serotonin transporters, respectively. However, in contrast to serotonin transporters from these two latter species, the Manduca transporter is inhibited poorly by fluoxetine (IC50 = 1.23 micro m) and cocaine (IC50 = 12.89 micro m). To delineate domains and residues that could play a role in cocaine interaction, the human serotonin transporter was mutated to incorporate unique amino acid substitutions, detected in the Manduca homologue. We identified a domain in extracellular loop 2 (amino acids 148-152), which, when inserted into the human transporter, results in decreased cocaine sensitivity of the latter (IC50 = 1.54 micro m). We also constructed a number of chimeras between the human and Manduca serotonin transporters (hSERT and MasSERT, respectively). The chimera, hSERT1-146/MasSERT106-587, which involved N-terminal swaps including transmembrane domains (TMDs) 1 and 2, was remarkably insensitive to cocaine (IC50 = 180 micro m) compared to the human (IC50 = 0.431 micro m) and Manduca serotonin transporters. The chimera MasSERT1-67/hSERT109-630, which involved only the TMD1 swap, showed greater sensitivity to cocaine (IC50 = 0.225 micro m) than the human transporter. Both chimeras showed twofold higher serotonin transport affinity compared to human and Manduca serotonin transporters. Our results show TMD1 and TMD2 affect the apparent substrate transport and antagonist sensitivity by possibly providing unique conformations to the transporter. The availability of these chimeras facilitates elucidation of specific amino acids involved in interactions with cocaine.
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Affiliation(s)
- Sumandeep K Sandhu
- Environmental Toxicology Graduate Program and Department of Cell Biology and Neuroscience, University of California, Riverside 92521, USA
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Abstract
Tachykinins are widely distributed in mammalian central nervous system and exert a variety of actions through individual specific receptors. Neurotransmitter functions of substance P (SP), a member of mammalian tachykinins, have been firmly established in the spinal cord; SP is highly concentrated in the superficial layers of the dorsal horn, is released upon electrical stimulation, produces a slow excitatory postsynaptic potential in second-order neurons and is inactivated by peptidases. Since SP is contained in unmyelinated primary afferent fibers, which mediate nociception, SP is thought to transmit nociceptive information and contribute to occurrence of pathological pain states such as inflammation and nerve injury. Based on these findings, great effort has been devoted to developing NK-1 tachykinin receptor antagonists as a potent antinociceptive drug, but up to the present such effective drugs are unavailable. Tachykinin receptor antagonists have been also attracting much attention as a novel therapeutic drug for anxiety and depression other than pain. The amygdala, a key brain structure associated with emotional responses, is thought to be a target of tachykinin receptor antagonists for exerting psychopharmacological actions. Indeed, tachykinins enhance inhibitory synaptic transmission in the basolateral complex of the amygdala. Further study of tachykininergic transmission in the central nervous systems will open novel fields for pharmacology and therapeutics in neuropsychiatric disorders.
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Prosser HM, Cooper DG, Forbes IT, Geppert M, Gribble AD, Grau EV, Groot PH, Harper AJ, Moores KE, Pickering SJ, Piercy V. Targeted replacement of rodent CCR2 with the human orthologue CCR2B: A mouse model for in vivo analysis of human target-selective small molecule MCP-1 receptor antagonists. Drug Dev Res 2002. [DOI: 10.1002/ddr.10044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rupniak NM, Carlson EJ, Webb JK, Harrison T, Porsolt RD, Roux S, de Felipe C, Hunt SP, Oates B, Wheeldon A. Comparison of the phenotype of NK1R-/- mice with pharmacological blockade of the substance P (NK1 ) receptor in assays for antidepressant and anxiolytic drugs. Behav Pharmacol 2001; 12:497-508. [PMID: 11742144 DOI: 10.1097/00008877-200111000-00011] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The phenotype of NK1R-/- mice was compared with that of acute pharmacological blockade of the tachykinin NK1 receptor on sensorimotor function and in assays relevant to depressive illness and anxiety. The dose range for L-760735 and GR205171 that was associated with functional blockade of central NK1 receptors in the target species was established by antagonism of the behavioural effects of intracerebroventricular NK1 agonist challenge in gerbils, mice and rats. The caudal grooming and scratching response to GR73632 was absent in NK1R-/- mice, confirming that the receptor had been genetically ablated. There was no evidence of sedation or motor impairment in NK1R-/- mice or following administration of L-760735 to gerbils, even at doses in excess of those required for central NK1 receptor occupancy. In the resident-intruder and forced swim test, the behaviour of NK1R-/- mice, or animals treated acutely with L-760735 or GR205171, resembled that seen with the clinically used antidepressant drug fluoxetine. However, the effects of GR205171 were not clearly enantioselective in mice. In contrast, although NK1R-/- mice also exhibited an increase in the duration of struggle behaviour in the tail suspension test, this was not observed following pharmacological blockade with L-760735 in gerbils or GR205171 in mice, suggesting that this may reflect a developmental alteration in the knockout mouse. There was no effect of NK1 receptor blockade with L-760735 in guinea-pigs or GR205171 in rats, or deletion of the NK1 receptor in mice, on behaviour in the elevated plus-maze test for anxiolytic activity. These findings extend previous observations on the phenotype of the NK1R-/- mouse and establish a broadly similar profile following acute pharmacological blockade of the receptor. These studies also serve to underscore the limitations of currently available antagonists that are suitable for use in rat and mouse behavioural assays.
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Affiliation(s)
- N M Rupniak
- Merck Sharp and Dohme Neuroscience Research Centre, Harlow, Essex, CM20 2QR, UK.
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Labrou NE, Bhogal N, Hurrell CR, Findlay JB. Interaction of Met297 in the seventh transmembrane segment of the tachykinin NK2 receptor with neurokinin A. J Biol Chem 2001; 276:37944-9. [PMID: 11489908 DOI: 10.1074/jbc.m106330200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We report the use of thiol chemistry to define specific and reversible disulfide interactions of Cys-substituted NK2 receptor mutants with analogues of neurokinin A (NKA) containing single cysteine substitutions. The NKA analogues were N-biotinylated to facilitate the rapid detection of covalent analogue-receptor interactions utilizing streptavidin reactivity. N-biotinyl-[Tyr1,Cys9]NKA, N-biotinyl-[Tyr1,Cys10]NKA were both found to reversibly disulfide bond to the NK2 receptor mutant Met297 --> Cys. This is consistent with the improved affinities of these particular analogues for the Met297 --> Cys receptor as compared with those for the wild-type and Met297 --> Leu receptors. In our three-dimensional model, Met297 occupies the equivalent position in helix 7 to the retinal binding Lys296 in rhodopsin. Binding of the NK2 receptor antagonist [3H]SR 48968 and of 125I-NKA was used to characterize additional receptor mutants. It seems that the aromatic residues Trp99 (helix 3), His198 (helix 5), Tyr266, His267, and Phe270 play an important role in NKA binding as structural determinants. The existence of overlapping SR 48968 and NKA binding sites is also evident. These data suggest that the peptide binding site of the NK2R is at least in part formed by residues buried deep within the transmembrane bundle and that this intramembranous binding domain may correspond to the binding sites for substantially smaller endogenous GPCR ligands.
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Affiliation(s)
- N E Labrou
- School of Biochemistry & Molecular Biology, The University of Leeds, Leeds, LS2 9JT United Kingdom
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Pawlak M, Schmidt RF, Heppelmann B, Hanesch U. The neurokinin-1 receptor antagonist RP 67580 reduces the sensitization of primary afferents by substance P in the rat. Eur J Pain 2001; 5:69-79. [PMID: 11394924 DOI: 10.1053/eujp.2000.0222] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The inflammatory mediator substance P (SP) produces a variety of biological effects in several tissues by binding to the tachykinin receptor neurokinin 1 (NK1) and, to a lesser extent, by binding to the neurokinin 2 receptor (NK2). To assess the sensitizing effect of SP on articular afferent fibres the NK1receptor antagonist RP 67580 was applied in normal and acutely inflamed rat knee joints. Altogether 38 fine afferent nerve fibres from the rat knee with conduction velocities of 0.71-13.5 m/s were recorded as single units, during non-noxious and noxious joint rotations. SP, injected i.a. as a bolus close to the knee joint, was able to sensitize 45.5% (10 of 22) of the units recorded from normal joints and 33.3% (five of 15) of afferents from inflamed joints. The following i.a. application of RP 67580 in a range of 20-200 nmol antagonized in a dose-dependent manner the sensitizing effect of SP in a large proportion of slowly conducting articular afferents from normal (66.7%) and inflamed (46.2%) knee joints. Subsequent SP application enhanced the afferent sensitivity further. The electrophysiological results presented here further support the suggestion that the sensitization of afferents by SP in the rat knee joint is mediated mainly by the NK1 receptor, which is probably located on the primary afferents.
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Affiliation(s)
- M Pawlak
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, D-97070 Würzburg, Federal Republic of Germany.
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