1
|
Martynov A, Farber B, Bomko T, Beckles DL, Kleyn I. Molecular Modeling, Synthesis, and Antihyperglycemic Activity of the New Benzimidazole Derivatives - Imidazoline Receptor Agonists. Drug Des Devel Ther 2024; 18:1035-1052. [PMID: 38585255 PMCID: PMC10999201 DOI: 10.2147/dddt.s447289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 02/28/2024] [Indexed: 04/09/2024] Open
Abstract
Introduction The paper presents the results of a study on the first synthesized benzimidazole derivatives obtained from labile nature carboxylic acids. The synthesis conditions of these substances were studied, their structure was proved, and some components were found to have sugar-reducing activity on the model of alloxan diabetes in rats. Methods The study used molecular modeling methods such as docking based on the evolutionary model (igemdock), RP_HPLC method to monitor the synthesis reaction, and 1H NMR and 13C NMR, and other methods of organic chemistry to confirm the structures of synthesized substances. Results & Discussion The docking showed that the ursodeoxycholic acid benzimidazole derivatives have high tropics to all imidazoline receptor carriers (PDB ID: 2XCG, 2bk3, 3p0c, 1QH4). The ursodeoxycholic acid benzimidazole derivative and arginine and histidine benzimidazole derivatives showed the highest sugar-lowering activity in the experiment on alloxan-diabetic rats. For these derivatives, the difference in glucose levels of treated rats was significant against untreated control. Therefore, the new derivatives of benzimidazole and labile natural organic acids can be used to create new classes of imidazoline receptor inhibitors for the treatment of diabetes mellitus and hypertension.
Collapse
Affiliation(s)
- Artur Martynov
- Laboratory and Clinical department of Molecular Immunopharmacology, SI “ I. Mechnikov Institute of Microbiology and Immunology of National Academy of Medical Sciences of Ukraine, Kharkiv, Ukraine
| | | | - Tatyana Bomko
- Laboratory and Clinical department of Molecular Immunopharmacology, SI “ I. Mechnikov Institute of Microbiology and Immunology of National Academy of Medical Sciences of Ukraine, Kharkiv, Ukraine
| | | | - Ilya Kleyn
- SUNY Downstate Medical Center / University Hospital of Brooklyn, New York, NY, USA
| |
Collapse
|
2
|
Siemian JN, Woodhouse K, Liu DH, Zhang Y, Li JX. The imidazoline I 2 receptor agonist 2-BFI reduces abuse-related effects of morphine: self-administration and drug discrimination. Psychopharmacology (Berl) 2024; 241:479-487. [PMID: 38159161 DOI: 10.1007/s00213-023-06524-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
RATIONALE Increasing evidence shows that imidazoline I2 receptor agonists enhance opioid-induced analgesia, suggesting that the combination of I2 receptor agonists with opioids could be a favorable strategy for pain control. However, the effect of I2 receptor agonists on the abuse liability of opioids is unknown. This study examined the impact of the I2 receptor agonist 2-BFI on some abuse-related behavioral effects of the opioid morphine in rats. OBJECTIVES The von Frey filament test was used to determine the antinociceptive effects of 2-BFI (intravenous, i.v.) in a rat model of complete Freund's adjuvant (CFA)-induced inflammatory pain. IV self-administration was used to assess the reinforcing effects of 2-BFI alone and to assess the effects of non-contingent injections of 2-BFI (i.p.) on morphine self-administration. A two-lever drug discrimination paradigm in which rats were trained to discriminate 3.2 mg/kg morphine (i.p.) from saline was used to examine whether 2-BFI or another I2 receptor agonist 2-(4,5-dihydroimidazol-2-yl)quinoline hydrochloride (BU224) affected the discriminative stimulus effects of morphine. RESULTS 2-BFI could not maintain reliable self-administration behavior in rats with no pain or CFA-treated inflammatory pain. However, pretreatment with 2-BFI (i.p.) produced dose-dependent decreases in the dose-effect curve of morphine self-administration. Both 2-BFI and BU224 did not substitute for morphine but significantly attenuated the discriminative stimulus effects of morphine. CONCLUSIONS These results suggest that I2 receptor agonists do not enhance, but in fact appear to decrease, the abuse liability of opioids, further supporting the potential utility of I2 receptor agonist-opioid combination therapy for pain control.
Collapse
Affiliation(s)
- Justin N Siemian
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Kristen Woodhouse
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | | | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
3
|
Araya EI, Chichorro JG. Editorial: Women in science: pharmacological treatment of pain. FRONTIERS IN PAIN RESEARCH 2023; 4:1231281. [PMID: 37441271 PMCID: PMC10334661 DOI: 10.3389/fpain.2023.1231281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Affiliation(s)
- Erika Ivanna Araya
- Department of Medicine, Headache and Neurological Pain Research Group, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | | |
Collapse
|
4
|
Puja G, Losi G, Rovati L, Lanza M, Caselli G, Bardoni R. Modulation of NMDA receptor activity by CR4056, an imidazoline-2 receptor ligand with analgesic properties. FRONTIERS IN PAIN RESEARCH 2022; 3:1003068. [DOI: 10.3389/fpain.2022.1003068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
CR4056 is an imidazoline-2 receptor ligand having potent analgesic activity and synergistic effect with opioids. Very recently it has been found that CR4056 can revert the cognitive impairment in animal models of Alzheimer's disease (AD). Since several lines of evidence highlight the importance of NMDAR modulators in nociceptive signaling and in AD progression, we considered as important to investigate the effects of CR4056 on NMDAR activity. In primary culture of cortical neurons, application of NMDA and glycine elicits a current that is decreased in a dose-dependent fashion by CR4056 (IC50 5.3 ± 0.1 µM). CR4056 antagonism is reversible, not competitive and voltage-independent and it is not blocked by pertussis toxin. CR4056 interacts with the co-agonist glycine site in a competitive way, indeed high glycine concentrations diminish its effect. Fibroblasts expressing different recombinant NMDA receptors are differently modulated by CR4056: the potency and the efficacy of the compound are higher in GluN1- GluN2B than in GluN1-GluN2A containing receptors. In lamina II neurons of spinal cord slices, single stimulation of afferent fibers evokes an NMDA-mediated current that is inhibited by 10 µM CR4056. Repetitive stimulation of the dorsal root at high frequency and high intensity produces a firing activity that is significatively depressed by CR4056. Taken together, our results broad the understanding of the molecular mechanisms of CR4056 analgesic activity, involving the modulation of NMDAR activity. Therefore, we propose that the analgesic action of CR4056 and the neuroprotective effects in AD models may be mediated also by NMDAR inhibition.
Collapse
|
5
|
Jiménez-Altayó F, Cabrera A, Bagán A, Giménez-Llort L, D’Ocon P, Pérez B, Pallàs M, Escolano C. An Imidazoline 2 Receptor Ligand Relaxes Mouse Aorta via Off-Target Mechanisms Resistant to Aging. Front Pharmacol 2022; 13:826837. [PMID: 35645795 PMCID: PMC9133327 DOI: 10.3389/fphar.2022.826837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
Imidazoline receptors (IR) are classified into three receptor subtypes (I1R, I2R, and I3R) and previous studies showed that regulation of I2R signaling has neuroprotective potential. In order to know if I2R has a role in modulating vascular tone in health and disease, we evaluated the putative vasoactive effects of two recently synthesized I2R ligands, diethyl (1RS,3aSR,6aSR)-5-(3-chloro-4-fluorophenyl)-4,6-dioxo-1-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole -1-phosphonate (B06) and diethyl [(1-(3-chloro-4-fluorobenzyl)-5,5-dimethyl-4-phenyl-4,5-dihydro-1H-imidazol-4-yl]phosphonate] (MCR5). Thoracic aortas from Oncins France 1 (3- to 4-months-old) and C57BL/6 (3- to 4- and 16- to 17-months-old mice) were mounted in tissue baths to measure isometric tension. In young mice of both strains, MCR5 induced greater relaxations than either B06 or the high-affinity I2R selective ligand 2-(2-benzofuranyl)-2-imidazoline (2-BFI), which evoked marginal responses. MCR5 relaxations were independent of I2R, as IR ligands did not significantly affect them, involved activation of smooth muscle KATP channels and inhibition of L-type voltage-gated Ca2+ channels, and were only slightly modulated by endothelium-derived nitric oxide (negatively) and prostacyclin (positively). Notably, despite the presence of endothelial dysfunction in old mice, MCR5 relaxations were preserved. In conclusion, the present study provides evidence against a functional contribution of I2R in the modulation of vascular tone in the mouse aorta. Moreover, the I2R ligand MCR5 is an endothelium-independent vasodilator that acts largely via I2R-independent pathways and is resistant to aging. We propose MCR5 as a candidate drug for the management of vascular disease in the elderly.
Collapse
Affiliation(s)
- Francesc Jiménez-Altayó
- Department of Pharmacology, Therapeutics and Toxicology, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
- *Correspondence: Francesc Jiménez-Altayó,
| | - Anna Cabrera
- Department of Pharmacology, Therapeutics and Toxicology, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Andrea Bagán
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
| | - Lydia Giménez-Llort
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
- Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Pilar D’Ocon
- Department of Pharmacology, School of Medicine, Universidad de Valencia, Burjassot, Spain
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, Valencia, Spain
| | - Belén Pérez
- Department of Pharmacology, Therapeutics and Toxicology, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mercè Pallàs
- Pharmacology Section, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, Institut de Neurociències, University of Barcelona, Barcelona, Spain
| | - Carmen Escolano
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
| |
Collapse
|
6
|
Sala E, Ferrari F, Lanza M, Milia C, Sabatini C, Bonazzi A, Comi E, Borsi Franchini M, Caselli G, Rovati LC. Improved efficacy, tolerance, safety, and abuse liability profile of the combination of CR4056 and morphine over morphine alone in rodent models. Br J Pharmacol 2020; 177:3291-3308. [PMID: 32154915 PMCID: PMC7312436 DOI: 10.1111/bph.15049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 02/14/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Prolonged use of opioids causes analgesic tolerance and adverse effects including constipation and dependence. Compounds targeting imidazoline I2 receptors are known to potentiate opioid analgesia in rodents. We investigated whether combination with the I2 receptor ligand CR4056 could improve efficacy and safety of morphine and explored the mechanisms of the CR4056-opioid interaction. EXPERIMENTAL APPROACH We used the complete Freund's adjuvant (CFA) model in rats to study the effects of treatments on hyperalgesia, morphine tolerance and microglia activation as measured by immunofluorescence. Opioid-induced adverse effects were assessed in rodent models of morphine-induced constipation, sedation (open field, sedation rating scale, and rotarod), physical dependence (naloxone-induced withdrawal), and abuse (conditioned place preference-associated reward). Chemiluminescence assays tested CR4056 as allosteric modulator of μ-opioid receptors. KEY RESULTS CR4056 (ED50 = 4.88 mg·kg-1 ) and morphine (ED50 = 2.07 mg·kg-1 ) synergized in reducing CFA-induced hyperalgesia (ED50 = 0.52 mg·kg-1 ; 1:1 combination). Consistently, low doses of CR4056 (1 mg·kg-1 ) spared one third of the cumulative morphine dose administered during 4 days and prevented/reversed the development of tolerance to morphine anti-hyperalgesia. These opioid-sparing effects were associated with decreased activation of microglia, independent of CR4056 interactions on μ-opioid receptors. Importantly, the low doses of CR4056 and morphine that synergize in analgesia did not induce constipation, sedation, physical dependence, or place preference. CONCLUSION AND IMPLICATIONS We showed selective synergism between CR4056 and morphine as analgesics. Their combination showed an improved safety and abuse liability profile over morphine alone. CR4056 could be developed as an opioid-sparing drug in multimodal analgesia.
Collapse
Affiliation(s)
- Emanuele Sala
- Rottapharm BiotechMonzaItaly
- PhD program in NeuroscienceUniversity of Milano‐BicoccaMonzaItaly
| | | | | | - Chiara Milia
- School of Medicine and SurgeryUniversity of Milano ‐ BicoccaMonzaItaly
| | - Chiara Sabatini
- Rottapharm BiotechMonzaItaly
- PhD program in NeuroscienceUniversity of Milano‐BicoccaMonzaItaly
| | | | | | | | | | | |
Collapse
|
7
|
Abás S, Rodríguez-Arévalo S, Bagán A, Griñán-Ferré C, Vasilopoulou F, Brocos-Mosquera I, Muguruza C, Pérez B, Molins E, Luque FJ, Pérez-Lozano P, de Jonghe S, Daelemans D, Naesens L, Brea J, Loza MI, Hernández-Hernández E, García-Sevilla JA, García-Fuster MJ, Radan M, Djikic T, Nikolic K, Pallàs M, Callado LF, Escolano C. Bicyclic α-Iminophosphonates as High Affinity Imidazoline I2 Receptor Ligands for Alzheimer’s Disease. J Med Chem 2020; 63:3610-3633. [DOI: 10.1021/acs.jmedchem.9b02080] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sònia Abás
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| | - Sergio Rodríguez-Arévalo
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| | - Andrea Bagán
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| | - Christian Griñán-Ferré
- Pharmacology Section, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institut de Neurociències, University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| | - Foteini Vasilopoulou
- Pharmacology Section, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institut de Neurociències, University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| | - Iria Brocos-Mosquera
- Department of Pharmacology, and Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, University of the Basque Country, UPV/EHU, E-48940 Leioa, Bizkaia, Spain
| | - Carolina Muguruza
- Department of Pharmacology, and Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, University of the Basque Country, UPV/EHU, E-48940 Leioa, Bizkaia, Spain
| | - Belén Pérez
- Department of Pharmacology, Therapeutic and Toxicology, Autonomous University of Barcelona, E-08193 Barcelona, Spain
| | - Elies Molins
- Institut de Ciència de Materials de Barcelona (CSIC), Campus UAB, E-08193 Cerdanyola, Spain
| | - F. Javier Luque
- Department of Nutrition, Food Sciences and Gastronomy, School of Pharmacy and Food Sciences, Institute of Biomedicine (IBUB), and Institute of Theoretical and Computational Chemistry (IQTCUB), University of Barcelona, E-08921 Santa Coloma de Gramanet, Spain
| | - Pilar Pérez-Lozano
- Unit of Pharmaceutical Technology, Pharmacy and Pharmaceutical Technology, and Physical Chemistry Department, Faculty of Pharmacy and Food Sciences, University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| | - Steven de Jonghe
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Dirk Daelemans
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - Lieve Naesens
- Rega Institute for Medical Research, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| | - José Brea
- Innopharma screening platform, BioFarma research group, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M. Isabel Loza
- Innopharma screening platform, BioFarma research group, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Elena Hernández-Hernández
- IUNICS University of the Balearic Islands (UIB), and Health Research Institute of the Balearic Islands (IdISBa), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain
| | - Jesús A. García-Sevilla
- IUNICS University of the Balearic Islands (UIB), and Health Research Institute of the Balearic Islands (IdISBa), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain
| | - M. Julia García-Fuster
- IUNICS University of the Balearic Islands (UIB), and Health Research Institute of the Balearic Islands (IdISBa), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain
| | - Milica Radan
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11000 Belgrade, Serbia
| | - Teodora Djikic
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11000 Belgrade, Serbia
| | - Katarina Nikolic
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11000 Belgrade, Serbia
| | - Mercè Pallàs
- Pharmacology Section, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institut de Neurociències, University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| | - Luis F. Callado
- Department of Pharmacology, and Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, University of the Basque Country, UPV/EHU, E-48940 Leioa, Bizkaia, Spain
| | - Carmen Escolano
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain
| |
Collapse
|
8
|
Vellani V, Sabatini C, Milia C, Caselli G, Lanza M, Letari O, Rovati LC, Giacomoni C. CR4056, a powerful analgesic imidazoline-2 receptor ligand, inhibits the inflammation-induced PKCε phosphorylation and membrane translocation in sensory neurons. Br J Pharmacol 2019; 177:48-64. [PMID: 31454418 DOI: 10.1111/bph.14845] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/10/2019] [Accepted: 08/12/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE CR4056 is a first-in-class imidazoline-2 (I2 ) receptor ligand characterized by potent analgesic activity in different experimental animal models of pain. In a recent phase II clinical trial, CR4056 effectively reduced pain in patients with knee osteoarthritis. In the present study, we investigated the effects of CR4056 on PKCε translocation in vitro and on PKCε activation in vivo in dorsal root ganglia (DRG) neurons. EXPERIMENTAL APPROACH Effects of CR4056 on bradykinin-induced PKCε translocation were studied in rat sensory neurons by immunocytochemistry. PKCε activation was investigated by immunohistochemistry analysis of DRG from complete Freund's adjuvant-treated animals developing local hyperalgesia. The analgesic activity of CR4056 was tested on the same animals. KEY RESULTS CR4056 inhibited PKCε translocation with very rapid and long-lasting activity. CR4056 decreased hyperalgesia and phospho-PKCε immunoreactivity in the DRG neurons innervating the inflamed paw. The effect of CR4056 on PKCε translocation was blocked by pertussis toxin, implying that the intracellular pathways involved Gi proteins. The inhibition of PKCε translocation by CR4056 was independent of the α2 -adrenoeceptor and, surprisingly, was also independent of idazoxan-sensitive I2 binding sites. The I2 agonist 2BFI had no effect alone but potentiated the activity of low concentrations of CR4056. CONCLUSIONS AND IMPLICATIONS Our results demonstrate that CR4056 shares the ability to inhibit PKCε translocation with other analgesics. Whether the inhibition of PKCε involves binding to specific subtype(s) of I2 receptors should be further investigated. If so, this would be a new mode of action of a highly specific I2 receptor ligand.
Collapse
Affiliation(s)
- Vittorio Vellani
- Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze, Università di Modena e Reggio Emilia, Modena, Italy
| | - Chiara Sabatini
- Rottapharm Biotech, Monza, Italy.,PhD Program in Neuroscience, Dipartimento di Medicina e chirurgia, Università degli Studi di Milano-Bicocca, Monza, Italy
| | - Chiara Milia
- PhD Program in Neuroscience, Dipartimento di Medicina e chirurgia, Università degli Studi di Milano-Bicocca, Monza, Italy
| | | | | | | | | | - Chiara Giacomoni
- Dipartimento di Economia, Scienze e Diritto, Università degli Studi della Repubblica di San Marino, San Marino
| |
Collapse
|
9
|
Siemian JN, Shang L, Seaman RW, Zhu Q, Zhang Y, Li JX. Effects of imidazoline I2 receptor agonists on reserpine-induced hyperalgesia and depressive-like behavior in rats. Behav Pharmacol 2019; 30:429-434. [PMID: 30383551 PMCID: PMC6494737 DOI: 10.1097/fbp.0000000000000454] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pharmacotherapies for fibromyalgia treatment are lacking. This study examined the antinociceptive and antidepressant-like effects of imidazoline I2 receptor (I2R) agonists in a reserpine-induced model of fibromyalgia in rats. Rats were treated for 3 days with vehicle or reserpine. The von Frey filament test was used to assess the antinociceptive effects of I2 receptor agonists, and the forced swim test was used to assess the antidepressant-like effects of these drugs. 2-BFI (3.2-10 mg/kg, intraperitoneally), phenyzoline (17.8-56 mg/kg, intraperitoneally), and CR4056 (3.2-10 mg/kg, intraperitoneally) all dose-dependently produced significant antinociceptive effects, which were attenuated by the I2R antagonist idazoxan. Only CR4056 significantly reduced the immobility time in the forced swim test in both vehicle-treated and reserpine-treated rats. These data suggest that I2R agonists may be useful to treat fibromyalgia-related pain and comorbid depression.
Collapse
Affiliation(s)
- Justin N. Siemian
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| | - Li Shang
- Department of Nursing, Affiliated Yantai Hospital of Binzhou Medical University, Yantai, Shandong, China
| | - Robert W. Seaman
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| | - Qing Zhu
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
- School of Pharmacy, Nantong University, Nantong, Jiangsu, China
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, North Carolina, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| |
Collapse
|
10
|
Griñán-Ferré C, Vasilopoulou F, Abás S, Rodríguez-Arévalo S, Bagán A, Sureda FX, Pérez B, Callado LF, García-Sevilla JA, García-Fuster MJ, Escolano C, Pallàs M. Behavioral and Cognitive Improvement Induced by Novel Imidazoline I 2 Receptor Ligands in Female SAMP8 Mice. Neurotherapeutics 2019; 16:416-431. [PMID: 30460457 PMCID: PMC6554384 DOI: 10.1007/s13311-018-00681-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
As populations increase their life expectancy, age-related neurodegenerative disorders such as Alzheimer's disease have become more common. I2-Imidazoline receptors (I2-IR) are widely distributed in the central nervous system, and dysregulation of I2-IR in patients with neurodegenerative diseases has been reported, suggesting their implication in cognitive impairment. This evidence indicates that high-affinity selective I2-IR ligands potentially contribute to the delay of neurodegeneration. In vivo studies in the female senescence accelerated mouse-prone 8 mice have shown that treatment with I2-IR ligands, MCR5 and MCR9, produce beneficial effects in behavior and cognition. Changes in molecular pathways implicated in oxidative stress, inflammation, synaptic plasticity, and apoptotic cell death were also studied. Furthermore, treatments with these I2-IR ligands diminished the amyloid precursor protein processing pathway and increased Aβ degrading enzymes in the hippocampus of SAMP8 mice. These results collectively demonstrate the neuroprotective role of these new I2-IR ligands in a mouse model of brain aging through specific pathways and suggest their potential as therapeutic agents in brain disorders and age-related neurodegenerative diseases.
Collapse
Affiliation(s)
- Christian Griñán-Ferré
- Pharmacology Section, Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institut de Neurociències, University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Foteini Vasilopoulou
- Pharmacology Section, Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institut de Neurociències, University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Sònia Abás
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Sergio Rodríguez-Arévalo
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Andrea Bagán
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Francesc X Sureda
- Pharmacology Unit, Faculty of Medicine and Health Sciences, University of Rovira and Virgili, C./St. Llorenç 21, 43201, Reus, Tarragona, Spain
| | - Belén Pérez
- Departament of Pharmacology, Therapeutic and Toxicology, Autonomous University of Barcelona, 08193, Barcelona, Spain
| | - Luis F Callado
- Department of Pharmacology, University of the Basque Country, UPV/EHU, 48940, Leioa, Bizkaia, Spain
- Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Leioa, Spain
| | - Jesús A García-Sevilla
- Laboratory of Neuropharmacology, IUNICS and IdISBa, University of the Balearic Islands (UIB), Cra. Valldemossa km 7.5, 07122, Palma de Mallorca, Spain
| | - M Julia García-Fuster
- Laboratory of Neuropharmacology, IUNICS and IdISBa, University of the Balearic Islands (UIB), Cra. Valldemossa km 7.5, 07122, Palma de Mallorca, Spain
| | - Carmen Escolano
- Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain
| | - Mercè Pallàs
- Pharmacology Section, Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institut de Neurociències, University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain.
| |
Collapse
|
11
|
Venkataraman AV, Keat N, Myers JF, Turton S, Mick I, Gunn RN, Rabiner EA, Passchier J, Parker CA, Tyacke RJ, Nutt DJ. First evaluation of PET-based human biodistribution and radiation dosimetry of 11C-BU99008, a tracer for imaging the imidazoline 2 binding site. EJNMMI Res 2018; 8:71. [PMID: 30062395 PMCID: PMC6066589 DOI: 10.1186/s13550-018-0429-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 07/18/2018] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND We measured whole body distribution of 11C-BU99008, a new PET biomarker for non-invasive identification of the imidazoline2 binding site. The purpose of this phase I study was to evaluate the biodistribution and radiation dosimetry of 11C-BU99008 in healthy human subjects. METHODS A single bolus injection of 11C-BU99008 (296 ± 10.5 MBq) was administered to four healthy subjects who underwent whole-body PET/CT over 120 min from the cranial vertex to the mid-thigh. Volumes of interest were drawn around visually identifiable source organs to generate time-activity curves (TAC). Residence times were determined from time-activity curves. Absorbed doses to individual organs and the whole body effective dose were calculated using OLINDA/EXM 1.1 for each subject. RESULTS The highest measured activity concentration was in the kidney and spleen. The longest residence time was in the muscle at 0.100 ± 0.023 h, followed by the liver at 0.067 ± 0.015 h and lungs at 0.052 ± 0.010 h. The highest mean organ absorbed dose was within the heart wall (0.028 ± 0.002 mGy/MBq), followed by the kidneys (0.026 ± 0.005 mGy/MBq). The critical organ was the heart wall. The total mean effective dose averaged over subjects was estimated to be 0.0056 ± 0.0004 mSv/MBq for an injection of 11C-BU99008. CONCLUSIONS The biodistribution of 11C-BU99008 has been shown here for the first time in humans. Our dosimetry data showed the total mean effective dose over all subjects was 0.0056 ± 0.0004 mSv/MBq, which would result in a total effective dose of 1.96 mSv for a typical injection of 350 MBq of 11C-BU99008. The effective dose is not appreciably different from those obtained with other 11C tracers.
Collapse
Affiliation(s)
- Ashwin V. Venkataraman
- Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, 5th Floor Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
- Restorative Neurosciences, Imperial College London, Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
| | - Nicholas Keat
- Imanova Limited, Imperial College London, Hammersmith Hospital, Burlington Danes Building, Du Cane Road, London, W12 0NN UK
| | - James F. Myers
- Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, 5th Floor Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
| | - Samuel Turton
- Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, 5th Floor Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
| | - Inge Mick
- Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, 5th Floor Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
| | - Roger N. Gunn
- Imanova Limited, Imperial College London, Hammersmith Hospital, Burlington Danes Building, Du Cane Road, London, W12 0NN UK
- Restorative Neurosciences, Imperial College London, Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
| | - Eugenii A. Rabiner
- Imanova Limited, Imperial College London, Hammersmith Hospital, Burlington Danes Building, Du Cane Road, London, W12 0NN UK
| | - Jan Passchier
- Imanova Limited, Imperial College London, Hammersmith Hospital, Burlington Danes Building, Du Cane Road, London, W12 0NN UK
| | - Christine A. Parker
- Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, 5th Floor Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
- Experimental Medicine Imaging, GlaxoSmithKline Research & Development Limited, Gunnels Wood Road, Stevenage, SG1 2NY UK
| | - Robin J. Tyacke
- Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, 5th Floor Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
| | - David J. Nutt
- Neuropsychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London, 5th Floor Burlington Danes Building, Hammersmith Hospital campus, 160 Du Cane Road, London, W12 0NN UK
| |
Collapse
|
12
|
Tian JS, Zhai QJ, Zhao Y, Chen R, Zhao LD. 2-(2-benzofuranyl)-2-imidazoline (2-BFI) improved the impairments in AD rat models by inhibiting oxidative stress, inflammation and apoptosis. J Integr Neurosci 2018; 16:385-400. [PMID: 28891528 DOI: 10.3233/jin-170032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Alzheimer's Disease (AD) is one of the commonest neural degeneration in aging population, and has become a global health challenge. 2-(2-benzofuranyl)-2-imidazoline (2-BFI) was reported to effectively improved the damage of patients with neuropathological disorders. In the present study, we investigated the effect of 2-BFI on the improvement of antioxidative, inflammation, and apoptosis in AD rats. Sprague-Dawley rats (2 months old, n=40) were used in this study and after injection of Aβ1-42 into hippocampal CA1 (Cornu Ammonis) region, the rats were given high, moderate and low dose of 2-BFI though intraperitoneal (i.p.) injection. Then spatial memory and navigation ability were analyzed by Morrize Water Maze. For the molecular testing, chemical colorimetry, ELISA and immunoblotting were performed to measure the activities of antioxidative enzymes, the abundance of immune cytokines and expression of apoptotic proteins, respectively. Hematoxylin and Eosin staining was used to analyze the pathological changes. We observed that 2-BFI significantly ameliorated the learning and memory abilities in rat models with AD by dosage treatment, as demonstrated by the shorten learning latency and greater times of travel across the platform quadrant. Additionally, reactive oxygen species (ROS) and malondialdehyde (MDA), were decreased after treatment of 2-BFI with dosage dependency, while the activities of superoxidase dismutase (SOD) and (GPX) Glutathione peroxidase were in turn enhanced, suggesting that 2-BFI could protect the antioxidative enzymes and reduce the oxidative stress in the hippocampus. Moreover, the expression of inflammatory factors including TNF-a and IL-1β were decreased after 2-BFI treatment. Additionally, the neuronal apoptosis was also attenuated, as shown by Western blot results. Taken together, the cognitive impairment in AD rats could be significantly improved by 2-BFI in a dose-dependent manner through suppressing oxidants accumulation, inhibiting of inflammatory response, as well as enhancing the neural viability.
Collapse
Affiliation(s)
- Ji-Sha Tian
- Department of Neurology, Huai'an Second People's Hospital, Huaian, Jiangsu, 223002, PR China
| | - Qi-Jin Zhai
- Department of Neurology, Huai'an Second People's Hospital, Huaian, Jiangsu, 223002, PR China
| | - Ying Zhao
- Department of Neurology, Huai'an Second People's Hospital, Huaian, Jiangsu, 223002, PR China
| | - Rui Chen
- Department of Neurology, Huai'an Second People's Hospital, Huaian, Jiangsu, 223002, PR China
| | - Lian-Dong Zhao
- Department of Neurology, Huai'an Second People's Hospital, Huaian, Jiangsu, 223002, PR China
| |
Collapse
|
13
|
Siemian JN, Wang K, Zhang Y, Li JX. Mechanisms of imidazoline I 2 receptor agonist-induced antinociception in rats: involvement of monoaminergic neurotransmission. Br J Pharmacol 2018; 175:1519-1534. [PMID: 29451703 DOI: 10.1111/bph.14161] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 12/17/2017] [Accepted: 02/04/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Although the antinociceptive efficacies of imidazoline I2 receptor agonists have been established, the exact post-receptor mechanisms remain unknown. This study tested the hypothesis that monoaminergic transmission is critical for I2 receptor agonist-induced antinociception. EXPERIMENTAL APPROACH von Frey filaments were used to assess antinociceptive effects of two I2 receptor agonists, 2-BFI and CR4056 on chronic constriction injury (CCI)-induced neuropathic pain or complete Freund's adjuvant (CFA)-induced inflammatory pain in rats. Rectal temperature was measured to assess hypothermic effects of 2-BFI. A two-lever drug discrimination paradigm in which rats were trained to discriminate 5.6 mg·kg-1 2-BFI (i.p.) from its vehicle was used to examine the discriminative stimulus effects of 2-BFI. In each experiment, pharmacological mechanisms were investigated by combining 2-BFI or CR4056 with various pharmacological manipulations of the monoaminergic system including selective reuptake inhibition, monoamine depletion and monoamine receptor antagonism. KEY RESULTS In the CCI model, selective reuptake inhibitors of 5-HT (fluoxetine) or noradrenaline (desipramine), but not dopamine (GBR12909), enhanced 2-BFI-induced antinociception. Selective depletion of 5-HT or noradrenaline almost abolished 2-BFI-induced antinociception. 5-HT1A , 5-HT2A and α1 -adrenoceptor antagonists, but not other monoaminergic antagonists, attenuated 2-BFI and CR4056-induced antinociception in CCI and/or CFA models. However, none of these monoamine receptor antagonists significantly altered 2-BFI-induced hypothermia or discriminative stimulus effects. CONCLUSIONS AND IMPLICATIONS Antinociception induced by I2 receptor agonists was mediated by serotonergic and noradrenergic mechanisms with 5-HT1A , 5-HT2A and α1 -adrenoceptor being particularly important. In contrast, the hypothermic and discriminative stimulus effects of I2 receptor agonists were mediated by distinct, independent mechanisms.
Collapse
Affiliation(s)
- Justin N Siemian
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY, USA
| | - Kaixuan Wang
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY, USA
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY, USA.,School of Pharmacy, Yantai University, Yantai, Shandong Province, China
| |
Collapse
|
14
|
Siemian JN, Jia S, Liu JF, Zhang Y, Li JX. Neuroanatomical characterization of imidazoline I 2 receptor agonist-induced antinociception. Eur J Neurosci 2018. [PMID: 29514408 DOI: 10.1111/ejn.13899] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chronic pain is a significant public health problem with a lack of safe and effective analgesics. The imidazoline I2 receptor (I2 R) is a promising analgesic target, but the neuroanatomical structures involved in mediating I2 R-associated behaviors are unknown. I2 Rs are enriched in the arcuate nucleus, dorsal raphe (DR), interpeduncular nucleus, lateral mammillary body, medial habenula, nucleus accumbens (NAc) and paraventricular nucleus; thus, this study investigated the antinociceptive and hypothermic effects of microinjections of the I2 R agonist 2-(2-benzofuranyl)-2-imidazoline hydrochloride (2-BFI). In rats, intra-DR microinjections produced antinociception in complete Freund's adjuvant- and chronic constriction injury-induced pain models. Intra-NAc microinjections produced antinociception and increased noxious stimulus-associated side time in a place escape/avoidance paradigm. Intra-NAc pretreatment with the I2 R antagonist idazoxan but not the D1 receptor antagonist SCH23390 or the D2 receptor antagonist raclopride attenuated intra-NAc 2-BFI-induced antinociception. Intra-NAc idazoxan did not attenuate systemically administered 2-BFI-induced antinociception. Microinjections into the other regions did not produce antinociception, and in none of the regions produced hypothermia. These data suggest that I2 R activation in some but not all I2 R-enriched brain regions is sufficient to produce antinociception and supports the theory that different I2 R-associated effects are mediated via distinct receptor populations, which may in turn be distributed differentially throughout the CNS.
Collapse
Affiliation(s)
- Justin N Siemian
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, 102 Farber Hall, 3435 Main St., Buffalo, NY, 14214, USA
| | - Shushan Jia
- Department of Anesthesiology, Yantai Affiliated Hospital, Binzhou Medical University, Yantai, China
| | - Jian-Feng Liu
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, 102 Farber Hall, 3435 Main St., Buffalo, NY, 14214, USA
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, 102 Farber Hall, 3435 Main St., Buffalo, NY, 14214, USA
| |
Collapse
|
15
|
Role of intracellular Ca 2+ signaling in the antinociceptive and discriminative stimulus effects of the imidazoline I 2 receptor agonist 2-BFI in rats. Psychopharmacology (Berl) 2017; 234:3299-3307. [PMID: 28825118 PMCID: PMC5660937 DOI: 10.1007/s00213-017-4719-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/13/2017] [Indexed: 01/27/2023]
Abstract
RATIONALE Recent research has established the imidazoline I2 receptor as a promising target for the development of novel analgesics. However, despite an increasing understanding of imidazoline I2 receptor-mediated behavioral effects, little is known about post-I2-receptor signaling mechanisms. OBJECTIVE This study examined the effects of several inhibitors of Ca2+ signaling mechanisms on two behavioral effects of the prototypical imidazoline I2 receptor ligand 2-(2-benzofuranyl)-2-imidazoline (2-BFI). METHODS The von Frey filament test was used to examine the antinociceptive effects of 2-BFI in complete Freund's adjuvant (CFA)-induced inflammatory pain in rats. A two-lever drug discrimination paradigm in which rats were trained to discriminate 5.6 mg/kg (intraperitoneally) 2-BFI from its vehicle was used to examine the discriminative stimulus effects of 2-BFI. RESULTS The L-type Ca2+ channel blockers verapamil and nimodipine, the calmodulin antagonist W-7, and the internal Ca2+ release inhibitor ryanodine all attenuated the antinociceptive effects of 2-BFI. Oxycodone- and acetaminophen-induced antinociception was unaffected by pretreatment with the Ca2+ channel blockers. Rats learned to reliably discriminate 5.6 mg/kg 2-BFI from saline. The I2 receptor agonists BU224, RS45041, tracizoline, and CR4056 all fully substituted for 5.6 mg/kg 2-BFI while idazoxan, S22687, 2,5-dimethoxy-4-methylamphetamine (DOM), and phenyzoline produced partial or no substitution. Verapamil, nimodipine, and W-7 did not alter the discriminative stimulus effects of 2-BFI. CONCLUSION These results indicate that the antinociceptive effects of 2-BFI involve intracellular Ca2+ elevation and/or downstream Ca2+/calmodulin signaling, whereas the discriminative stimulus effects of 2-BFI are mediated by a distinct, independent mechanism.
Collapse
|
16
|
Tolerance and cross-tolerance to the antinociceptive effects of oxycodone and the imidazoline I 2 receptor agonist phenyzoline in adult male rats. Psychopharmacology (Berl) 2017; 234:1871-1880. [PMID: 28314949 PMCID: PMC5451304 DOI: 10.1007/s00213-017-4599-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 03/08/2017] [Indexed: 10/19/2022]
Abstract
RATIONALE Emerging evidence suggests the potential utility of combining opioids with imidazoline I2 receptor agonists for chronic pain. However, chronic pain management requires prolonged pharmacotherapy, and the consequence of such combination therapy remains unclear. OBJECTIVE This study examined the anti-hyperalgesic effect of the opioid oxycodone, the selective I2 receptor agonist phenyzoline, alone and in combination, during prolonged treatment. METHODS Von Frey filament test was used to examine the anti-hyperalgesic effect of drugs in complete Freund's adjuvant (CFA)-induced inflammatory pain or chronic constriction injury (CCI)-induced neuropathic pain in rats. Twice-daily treatment with oxycodone and phenyzoline, alone or in combination, was continued until the development of significant tolerance (oxycodone) or as long as 19 days passed (phenyzoline). RESULTS In rats receiving CFA or CCI manipulation, mechanical hyperalgesia was dose-dependently reversed by oxycodone and phenyzoline. Twice-daily treatment with 2 × ED50 dose of oxycodone for 7 days led to significant antinociceptive tolerance to oxycodone but not cross-tolerance to phenyzoline. Similarly, twice-daily treatment with 2 × ED50 dose of phenyzoline for 19 days led to significant antinociceptive tolerance to phenyzoline but not cross-tolerance to oxycodone. Twice-daily treatment with the combined oxycodone and phenyzoline using different ratios (1:3, 1:1 and 3: 1) at the doses that were functionally equivalent to the treatment doses of oxycodone and phenyzoline for 13-19 days generally led to delayed antinociceptive tolerance. CONCLUSIONS Combination therapy with oxycodone and I2 receptor agonists maintains prolonged antinociceptive effectiveness with reduced propensity to develop tolerance.
Collapse
|
17
|
Comi E, Lanza M, Ferrari F, Mauri V, Caselli G, Rovati LC. Efficacy of CR4056, a first-in-class imidazoline-2 analgesic drug, in comparison with naproxen in two rat models of osteoarthritis. J Pain Res 2017; 10:1033-1043. [PMID: 28496359 PMCID: PMC5422496 DOI: 10.2147/jpr.s132026] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Purpose CR4056, (2-phenyl-6-(1H-imidazol-1yl) quinazoline), an imidazoline-2 (I2) receptor ligand, is a promising analgesic drug that has been reported to be effective in several animal models of pain. The aim of this study was to evaluate the effects of CR4056 in two well-established rat models of osteoarthritis (OA), mimicking the painful and structural components of human OA. Methods Knee OA was induced either by single intra-articular injection of monoiodoacetate (MIA) or by medial meniscal tear (MMT) in the right knee of male rats. In the MIA model, allodynia and hyperalgesia were measured as paw withdrawal threshold to mechanical stimulation. In the MMT model, pain behavior was analyzed as weight-bearing asymmetry (i.e. difference in hind paw weight distribution, HPWD) between the injured and the contralateral limbs. Results Acute oral administration of CR4056, 14 days after MIA injection, significantly and dose-dependently reduced allodynia and hyperalgesia 90 minutes after treatment, whereas acute naproxen administration significantly reduced allodynia but not hyperalgesia. After 7 days of repeated treatment, both CR4056 and naproxen showed significant anti-allodynic and anti-hyperalgesic effects in the MIA model. Rats undergoing MMT surgery developed a significant and progressive asymmetry in HPWD compared with sham-operated animals. Repeated treatment with CR4056 significantly reduced the progression of the pain behavior, whereas naproxen had no effects. Conclusion The data presented here show that the I2 ligand CR4056 could be a new effective treatment for OA pain. The compound is currently under Phase II clinical evaluation for this indication.
Collapse
Affiliation(s)
- Eleonora Comi
- Department of Pharmacology and Toxicology, Rottapharm Biotech.,PhD Program in Neuroscience, University of Milan-Bicocca
| | - Marco Lanza
- Department of Pharmacology and Toxicology, Rottapharm Biotech
| | - Flora Ferrari
- Department of Pharmacology and Toxicology, Rottapharm Biotech
| | - Valeria Mauri
- Department of Pharmacology and Toxicology, Rottapharm Biotech.,Department of Surgery and Translational Medicine, University of Milan-Bicocca, Monza, Italy
| | | | | |
Collapse
|
18
|
Abstract
Since first introduced more than two decades ago, the research in imidazoline I2 receptors has been steadily increasing. This review provides an update on the current status of I2 receptor pharmacology. Imidazoline I2 receptors or I2 binding sites refer to several (at least four) different proteins that bind to [3H]-idazoxan and [3H]-2-BFI with high affinity. The molecular identities of the proteins remain elusive. One of the proteins (45kD) seems to be consistent with the identity of brain creatine kinase. The biological functions of I2 receptors have been primarily unveiled by the studies of selective I2 receptor ligands. Accumulating evidence suggests that I2 receptor ligands are effective analgesics for persistent and chronic painful conditions such as inflammatory, neuropathic and postoperative pain. One selective I2 receptor ligand, CR4056, has been advanced to phase II clinical trial with the therapeutic indication of chronic inflammatory pain (osteoarthritis). The expansion to the treatment of other chronic pain conditions should be expected if CR4056 could eventually be approved as a new drug. I2 receptor ligands also demonstrate robust discriminative stimulus activity and induce a characteristic discriminative cue in animals. Biochemical and preclinical in vivo investigations also suggest that I2 receptor ligands have neuroprotective activity and modulate body temperature. The emerging discrepancies of a range of purported selective I2 receptor ligands suggest different pharmacological effects mediated by discrete I2 receptor components which likely attribute to the I2 receptor-related proteins. It is proposed that the I2 receptors represent an emerging drug target for the treatment of neurological disorders such as pain and stroke, and deserve more research attention to translate preclinical findings to pharmacotherapies.
Collapse
Affiliation(s)
- Jun-Xu Li
- School of Pharmacy, Nantong University, Nantong, Jiangsu Province, China; Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.
| |
Collapse
|
19
|
Thorn DA, Qiu Y, Zhang Y, Li JX. Antinociceptive effects of imidazoline I2 receptor agonists in the formalin test in rats. Behav Pharmacol 2016; 27:377-83. [PMID: 26599907 PMCID: PMC4842102 DOI: 10.1097/fbp.0000000000000206] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The imidazoline I2 receptor is an emerging drug target for analgesics. This study extended previous studies by examining the antinociceptive effects of three I2 receptor agonists (2-BFI, BU224, and CR4056) in the formalin test. The receptor mechanisms and anatomical mediation of I2 receptor agonist-induced antinociception were also examined. Formalin-induced flinching responses (2%, 50 μl) were quantified after treatment with I2 receptor agonists alone or in combination with the I2 receptor antagonist idazoxan. Anatomical mediation was studied by locally administering 2-BFI into the plantar surface or into the right lateral ventricle through cannulae (intracerebroventricular). The locomotor activity was also examined after central (intracerebroventricular) administration of 2-BFI. 2-BFI (1-10 mg/kg, intraperitoneal) and BU224 (1-10 mg/kg, intraperitoneal) attenuated the spontaneous flinching response observed during 10 min (phase 1) and 20-60 min (phase 2) following formalin treatment, whereas CR4056 (1-32 mg/kg, intraperitoneal) decreased only phase 2 flinching response. The I2 receptor antagonist idazoxan attenuated the antinociceptive effects of 2-BFI and BU224 during phase 1, but not phase 2. Peripheral administration of 2-BFI (1-10 mg/kg, intraplantar) to the hind paw of rats had no antinociceptive effect. In contrast, centrally delivered 2-BFI (10-100 µg, intracerebroventricular) dose-dependently attenuated phase 1 and phase 2 flinching at doses that did not reduce the locomotor activity. Together, these data revealed the differential antinociceptive effects of I2 receptor agonists and the differential antagonism profiles by idazoxan, suggesting the involvement of different I2 receptor subtypes in reducing different phases of formalin-induced pain-like behaviors. In addition, the results also suggest the central mediation of I2 receptor agonist-induced antinociceptive actions.
Collapse
Affiliation(s)
- David A Thorn
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| | - Yanyan Qiu
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, North Caroline, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| |
Collapse
|
20
|
Lanza M, Ferrari F, Menghetti I, Tremolada D, Caselli G. Modulation of imidazoline I2 binding sites by CR4056 relieves postoperative hyperalgesia in male and female rats. Br J Pharmacol 2016; 171:3693-701. [PMID: 24758515 PMCID: PMC4128066 DOI: 10.1111/bph.12728] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 03/27/2014] [Accepted: 04/09/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE CR4056 is a novel imidazoline-2 (I2 ) ligand exhibiting potent analgesic activity in animal models of pain. In this study, we investigated the effects of CR4056 in a well-established model of postoperative pain where rats develop hyperalgesia in the injured hind paw. EXPERIMENTAL APPROACH By measuring paw withdrawal threshold to mechanical pressure, we studied the pharmacology of CR4056, potential sex differences in pain perception and response to treatment, and the pharmacodynamic interaction of CR4056 with morphine. KEY RESULTS Oral CR4056 and subcutaneous morphine dose-dependently reversed the hyperalgesic response. Analgesic effects of CR4056 were completely suppressed by the non-selective imidazoline I2 /α2 -adrenoceptor antagonist idazoxan, were partially reduced (~30%; P < 0.05) by the selective α2 -adrenoceptor antagonist yohimbine, but were not influenced by the non-selective I1 /α2 -adrenoceptor antagonist efaroxan or by the μ opioid receptor antagonist naloxone. We found no differences in responses to CR4056 or morphine between male and female rats. However, females had a lower pain threshold than males, and needed lower doses of drugs to reach a significant analgesia. When CR4056 and morphine were combined, their median effective doses were lower than expected for additive effects, both in males and in females. Isobolographic analysis confirmed a synergism between CR4056 and morphine. CONCLUSIONS AND IMPLICATIONS CR4056 is a novel pharmacological agent under development for postoperative pain both as stand-alone treatment and in association with morphine. CR4056 has successfully completed Phase I studies for tolerability and pharmacokinetics in healthy volunteers, and is currently entering the first proof-of-concept study in patients.
Collapse
Affiliation(s)
- Marco Lanza
- Department of Pharmacology & Toxicology, Rottapharm Biotech S.r.l., Monza, MB, Italy
| | | | | | | | | |
Collapse
|
21
|
Siemian JN, Obeng S, Zhang Y, Zhang Y, Li JX. Antinociceptive Interactions between the Imidazoline I2 Receptor Agonist 2-BFI and Opioids in Rats: Role of Efficacy at the μ-Opioid Receptor. J Pharmacol Exp Ther 2016; 357:509-19. [PMID: 27056847 DOI: 10.1124/jpet.116.232421] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/07/2016] [Indexed: 12/14/2022] Open
Abstract
Although μ-opioids have been reported to interact favorably with imidazoline I2 receptor (I2R) ligands in animal models of chronic pain, the dependence on the μ-opioid receptor ligand efficacy on these interactions had not been previously investigated. This study systematically examined the interactions between the selective I2 receptor ligand 2-(2-benzofuranyl)-2-imidazoline hydrochloride (2-BFI) and three μ-opioid receptor ligands of varying efficacies: fentanyl (high efficacy), buprenorphine (medium-low efficacy), and 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6α-[(3'-isoquinolyl) acetamido] morphine (NAQ; very low efficacy). The von Frey test of mechanical nociception and Hargreaves test of thermal nociception were used to examine the antihyperalgesic effects of drug combinations in complete Freund's adjuvant-induced inflammatory pain in rats. Food-reinforced schedule-controlled responding was used to examine the rate-suppressing effects of each drug combination. Dose-addition and isobolographical analyses were used to characterize the nature of drug-drug interactions in each assay. 2-BFI and fentanyl fully reversed both mechanical and thermal nociception, whereas buprenorphine significantly reversed thermal but only slightly reversed mechanical nociception. NAQ was ineffective in both nociception assays. When studied in combination with fentanyl, NAQ acted as a competitive antagonist (apparent pA2 value: 6.19). 2-BFI/fentanyl mixtures produced additive to infra-additive analgesic interactions, 2-BFI/buprenorphine mixtures produced supra-additive to infra-additive interactions, and 2-BFI/NAQ mixtures produced supra-additive to additive interactions in the nociception assays. The effects of all combinations on schedule-controlled responding were generally additive. Results consistent with these were found in experiments using female rats. These findings indicate that lower-efficacy μ-opioid receptor agonists may interact more favorably with I2R ligands than high-efficacy μ-opioid receptor agonists.
Collapse
Affiliation(s)
- Justin N Siemian
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York (J.N.S., J.-X.L.); Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (S.O., Yan.Z.); and Research Triangle Institute, Research Triangle Park, North Carolina (Yanan.Z.)
| | - Samuel Obeng
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York (J.N.S., J.-X.L.); Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (S.O., Yan.Z.); and Research Triangle Institute, Research Triangle Park, North Carolina (Yanan.Z.)
| | - Yan Zhang
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York (J.N.S., J.-X.L.); Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (S.O., Yan.Z.); and Research Triangle Institute, Research Triangle Park, North Carolina (Yanan.Z.)
| | - Yanan Zhang
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York (J.N.S., J.-X.L.); Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (S.O., Yan.Z.); and Research Triangle Institute, Research Triangle Park, North Carolina (Yanan.Z.)
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York (J.N.S., J.-X.L.); Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (S.O., Yan.Z.); and Research Triangle Institute, Research Triangle Park, North Carolina (Yanan.Z.)
| |
Collapse
|
22
|
Siemian JN, Li J, Zhang Y, Li JX. Interactions between imidazoline I2 receptor ligands and acetaminophen in adult male rats: antinociception and schedule-controlled responding. Psychopharmacology (Berl) 2016; 233:873-82. [PMID: 26613734 PMCID: PMC4752914 DOI: 10.1007/s00213-015-4166-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/18/2015] [Indexed: 01/01/2023]
Abstract
RATIONALE Recent evidence suggests that imidazoline I2 receptor ligands are suitable for combination therapy with opioids. Quantitative analysis of I2 receptor ligands combined with non-opioid drugs is necessary for the justification of alternative pain therapies. OBJECTIVE This study systematically examined the antihyperalgesic and response rate-suppressing effects of selective I2 receptor ligands (2-BFI and phenyzoline) alone and in combination with acetaminophen. METHODS Von Frey and Hargreaves tests were used to examine the antihyperalgesic effects of drugs in complete Freund's adjuvant (CFA)-induced inflammatory pain in rats. Food-reinforced schedule-controlled responding was used to assess the rate-suppressing effects of study drugs. Dose-addition and isobolographic analyses were used to assess drug-drug interactions for all assays. RESULTS 2-BFI (3.2-17.8 mg/kg, i.p.), phenyzoline (17.8-100 mg/kg, i.p.), and acetaminophen (56-178 mg/kg, i.p.) all dose-dependently produced significant antinociceptive effects. When studied as combinations, 2-BFI and acetaminophen produced infra-additive to additive interactions while phenyzoline and acetaminophen produced additive to supra-additive interactions. The same drug combinations suppressed response rate in a supra-additive manner. CONCLUSIONS Quantitative analysis of the antihyperalgesic and response rate-suppressing effects suggests that I2 receptor ligands are not well suited to combination therapy with acetaminophen.
Collapse
Affiliation(s)
- Justin N. Siemian
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, New York, USA
| | - Jiuzhou Li
- Department of Neurosurgery, Binzhou People’s Hospital, Binzhou, Shandong Province, China
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, North Carolina, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
23
|
Thorn DA, Zhang Y, Li JX. Effects of the imidazoline I2 receptor agonist 2-BFI on the development of tolerance to and behavioural/physical dependence on morphine in rats. Br J Pharmacol 2016; 173:1363-72. [PMID: 26776953 DOI: 10.1111/bph.13435] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 01/07/2015] [Accepted: 01/12/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE This study examined the effects of imidazoline I2 receptor agonists on the development of tolerance to and physical dependence on repeated morphine treatment in rats. EXPERIMENTAL APPROACH Two groups of rats (n = 9 per group) were trained to lever press for sucrose (10%) presentation under a fixed-ratio 10 schedule. The rate-suppressing effects of the opioid receptor ligands morphine and naltrexone and the I2 receptor agonist 2-BFI were examined weekly in rats treated with either daily morphine (20 mg·kg(-1) , s.c.), alone or in combination with 2-BFI (10 mg·kg(-1) ) for 3 weeks. Changes in body weight were measured following naltrexone tests in both groups of rats. In separate experiments, the antinociceptive effects of morphine were assessed using a warm-water tail-withdrawal procedure in rats before and after daily treatments (7 days) with morphine (32 mg·kg(-1) , i.p.) alone or in combination with various doses of the I2 receptor agonists 2-BFI, BU224 and CR4056. KEY RESULTS Daily treatment for 3 weeks, with morphine in combination with 2-BFI produced significantly less tolerance to the rate-suppressing effects of morphine and produced a decreased sensitivity to the rate-suppressing effects of naltrexone as well as decreased naltrexone-induced weight loss, compared with morphine-alone group. Repeated treatment for 7 days with morphine produced antinociceptive tolerance, which was attenuated by co-administration with 2-BFI, BU224 or CR4056. CONCLUSIONS AND IMPLICATIONS Imidazoline I2 receptor agonists attenuated the development of tolerance to and physical dependence on morphine, further supporting the therapeutic potential of combining I2 receptor agonists and opioids for pain treatment.
Collapse
Affiliation(s)
- David A Thorn
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY, USA
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, Durham, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY, USA
| |
Collapse
|
24
|
Anti-hyperalgesic effects of imidazoline I2 receptor ligands in a rat model of inflammatory pain: interactions with oxycodone. Psychopharmacology (Berl) 2015; 232:3309-18. [PMID: 26037946 PMCID: PMC4537836 DOI: 10.1007/s00213-015-3983-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/24/2015] [Indexed: 10/23/2022]
Abstract
RATIONALE Emerging preclinical evidence suggests that imidazoline I2 receptor ligands may be effective analgesics. Quantitative analysis of the combined I2 receptor ligands and opioids is needed for the justification of combination therapy. OBJECTIVE This study systematically examined the anti-hyperalgesic and response rate-suppressing effects of selective I2 receptor ligands (2-BFI and phenyzoline) alone and in combination with oxycodone in rats. METHODS Von Frey filament test was used to examine the anti-hyperalgesic effects of drugs in a rat model of complete Freund's adjuvant (CFA)-induced inflammatory pain. Schedule-controlled responding was used to assess the rate-altering effects of study drugs. Duration of actions of individual drugs (2-BFI, phenyzoline, and oxycodone) alone or in combination was studied. Dose-addition analysis was employed to assess the anti-hyperalgesic interactions between drugs. RESULTS Oxycodone (0.1-3.2 mg/kg, i.p.), 2-BFI (1-17.8 mg/kg, i.p.), and phenyzoline (17.8-56 mg/kg, i.p.) all dose-dependently produced significant antinociceptive effects. When studied as combinations, 2-BFI and oxycodone produced additive interactions while phenyzoline and oxycodone produced supra-additive interactions under all fixed ratios. The same drug combinations did not alter or significantly reduced the operant responding depending on the ratios of the drug combinations. CONCLUSIONS Quantitative analysis of the anti-hyperalgesic effects of I2 receptor ligands strongly supports the therapeutic potential of I2 receptor ligands against inflammatory pain. In addition, the data reveal that phenyzoline is superior to the prototypic I2 receptor ligand 2-BFI for the management of pain and warrants further consideration as a novel analgesic.
Collapse
|
25
|
Bektas N, Nemutlu D, Arslan R. The imidazoline receptors and ligands in pain modulation. Indian J Pharmacol 2015; 47:472-8. [PMID: 26600633 PMCID: PMC4621665 DOI: 10.4103/0253-7613.165196] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/22/2015] [Accepted: 08/09/2015] [Indexed: 11/11/2022] Open
Abstract
Pain is an unpleasant experience and effects daily routine negatively. Although there are various drugs, many of them are not entirely successful in relieving pain, since pain modulation is a complex process involving numerous mediators and receptors. Therefore, it is a rational approach to identify the factors involved in the complex process and develop new agents that act on these pain producing mechanisms. In this respect, the involvement of the imidazoline receptors in pain modulation has drawn attention in recent years. In this review, it is aimed to focus on the imidazoline receptors and their ligands which contribute to the pain modulation. It is demonstrated that imidazoline-2 (I2) receptors are steady new drug targets for analgesics. Even if the mechanism of I2 receptor is not well known in the modulation of pain, it is known that it plays a role in tonic and chronic pain but not in acute phasic pain. Moreover, the I2 receptor ligands increase the analgesic effects of opioids in both acute and chronic pain and prevent the development of opioid tolerance. So, they are valuable for the chronic pain treatment and also therapeutic coadjuvants in the management of chronic pain with opiate drugs due to the attenuation of opioid tolerance and addiction. Thus, the use of the ligands which bind to the imidazoline receptors is an effective strategy for relieving pain. This educational forum exhibits the role of imidazoline receptors and ligands in pain process by utilizing experimental studies.
Collapse
Affiliation(s)
- Nurcan Bektas
- Department of Pharmacology, Faculty of Pharmacy, Anadolu University, Eskisehir 26470, Turkey
| | - Dilara Nemutlu
- Department of Pharmacology, Faculty of Pharmacy, Anadolu University, Eskisehir 26470, Turkey
| | - Rana Arslan
- Department of Pharmacology, Faculty of Pharmacy, Anadolu University, Eskisehir 26470, Turkey
| |
Collapse
|
26
|
Qiu Y, Zhang Y, Li JX. Discriminative stimulus effects of the imidazoline I2 receptor ligands BU224 and phenyzoline in rats. Eur J Pharmacol 2015; 749:133-41. [PMID: 25617792 DOI: 10.1016/j.ejphar.2015.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 01/25/2023]
Abstract
Although imidazoline I2 receptor ligands have been used as discriminative stimuli, the role of efficacy of I2 receptor ligands as a critical determinant in drug discrimination has not been explored. This study characterized the discriminative stimulus effects of selective imidazoline I2 receptor ligands BU224 (a low-efficacy I2 receptor ligand) and phenyzoline (a higher efficacy I2 receptor ligand) in rats. Two groups of male Sprague-Dawley rats were trained to discriminate 5.6mg/kg BU224 or 32mg/kg phenyzoline (i.p.) from their vehicle in a two-lever food-reinforced drug discrimination procedure, respectively. All rats acquired the discriminations after an average of 18 (BU224) and 56 (phenyzoline) training sessions, respectively. BU224 and phenyzoline completely substituted for one another symmetrically. Several I2 receptor ligands (tracizoline, CR4056, RS45041, and idazoxan) all occasioned>80% drug-associated lever responding in both discriminations. The I2 receptor ligand 2-BFI and a monoamine oxidase inhibitor harmane occasioned>80% drug-associated lever responding in rats discriminating BU224. Other drugs that occasioned partial or less substitution to BU224 cue included clonidine, methamphetamine, ketamine, morphine, methadone and agmatine. Clonidine, methamphetamine and morphine also only produced partial substitution to phenyzoline cue. Naltrexone, dopamine D2 receptor antagonist haloperidol and serotonin (5-HT)2A receptor antagonist MDL100907 failed to alter the discriminative stimulus effects of BU224 or phenyzoline. Combined, these results are the first to demonstrate that BU224 and phenyzoline can serve as discriminative stimuli and that the low-efficacy I2 receptor ligand BU224 shares similar discriminative stimulus effects with higher-efficacy I2 receptor ligands such as phenyzoline and 2-BFI.
Collapse
Affiliation(s)
- Yanyan Qiu
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
27
|
Abstract
The imidazoline I2 receptor ligand BU99006 binds to and attenuates effects mediated by I2 receptors in vitro, although its effects in vivo have not been studied previously. This study examined the effects of BU99006 in two behavioral assays in rats: hypothermia and 2-BFI discrimination. BU99006 (3.2-15 mg/kg, intraperitoneally) produced a dose-dependent hypothermic effect (rectal temperature), which was antagonized by the I2 receptor antagonist idazoxan. BU99006 (3.2 or 10 mg/kg administered 10 min or 2 h before the session, respectively) did not significantly alter hypothermia produced by the I2 receptor agonist 2-BFI (10 mg/kg). In rats discriminating 5.6 mg/kg 2-BFI, BU99006 (1.78-17.8 mg/kg, intraperitoneally) produced 40 and 82% responding on the 2-BFI-associated lever when it was administered immediately or 2 h before the test sessions, respectively. BU99006 enhanced the discriminative stimulus and rate-suppressing effects of 2-BFI. Collectively, these data suggest that BU99006 is an imidazoline I2 receptor agonist with no evidence of I2 receptor antagonism in rats.
Collapse
|
28
|
Li JX, Thorn DA, Qiu Y, Peng BW, Zhang Y. Antihyperalgesic effects of imidazoline I(2) receptor ligands in rat models of inflammatory and neuropathic pain. Br J Pharmacol 2014; 171:1580-90. [PMID: 24329196 DOI: 10.1111/bph.12555] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE A new imidazoline I2 receptor ligand, CR4056, is effective for chronic inflammatory pain and diabetic neuropathy. However, it is unclear whether other I2 receptor ligands have similar effects and whether antinociceptive tolerance develops with repeated treatment. EXPERIMENTAL APPROACH The Von Frey filament test was used to measure mechanical hyperalgesia and the plantar test to measure thermal hyperalgesia in rats injected with complete Freund's adjuvant (CFA) treatment or had undergone surgery to induce chronic constriction injury (CCI), models of inflammatory pain and peripheral neuropathic pain respectively. The effects of morphine and I2 receptor ligands, 2-BFI, BU224, tracizoline and CR4056, 3.2-32 mg·kg(-1) , i.p., on hyperalgesia or affective pain (as measured by a place escape/avoidance paradigm) were studied in separate experiments. KEY RESULTS Morphine and the I2 receptor ligands (2-BFI, BU224 and tracizoline) all dose-dependently attenuated mechanical and thermal hyperalgesia in CFA-treated rats. The anti-hyperalgesic effects of 2-BFI in CFA-treated and CCI rats were attenuated by the I2 receptor antagonist idazoxan. The combination of 2-BFI and morphine produced additive effects against mechanical hyperalgesia in CFA-treated rats. Repeated treatment (daily for 7-9 days) with 2-BFI or CR4056 did not produce antinociceptive tolerance in CFA-treated or CCI rats. Morphine and the I2 receptor ligands (2-BFI, BU224 and CR4056) were all effective at attenuating place escape/avoidance behaviour in CFA-treated rats. CONCLUSIONS AND IMPLICATIONS Imidazoline I2 receptor ligands have antihyperalgesic effects in rat models of inflammatory and neuropathic pain and may represent a new class of pharmacotherapeutics for the management of chronic pain.
Collapse
Affiliation(s)
- Jun-Xu Li
- Department of Pharmacology and Toxicology, University at Buffalo, Buffalo, NY, USA
| | | | | | | | | |
Collapse
|
29
|
Qiu Y, He XH, Zhang Y, Li JX. Discriminative stimulus effects of the novel imidazoline I₂ receptor ligand CR4056 in rats. Sci Rep 2014; 4:6605. [PMID: 25308382 PMCID: PMC4194429 DOI: 10.1038/srep06605] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/22/2014] [Indexed: 01/27/2023] Open
Abstract
This study examined whether a novel imidazoline I2 receptor ligand CR4056 could serve as a discriminative stimulus and whether it shares similar discriminative stimulus effects with other reported I2 receptor ligands. Eight male Sprague-Dawley rats were trained to discriminate 10.0 mg/kg CR4056 (i.p.) from vehicle in a two-lever food-reinforced drug discrimination procedure. Once rats acquired the discrimination, substitution and combination studies were conducted to elucidate the underlying receptor mechanisms. All rats acquired CR4056 discrimination after an average of 26 training sessions. Several I2 receptor ligands (phenyzoline, tracizoline, RS45041, and idazoxan, 3.2–75 mg/kg, i.p.) all occasioned > 80% CR4056-associated lever responding. Other drugs that occasioned partial or no CR4056-associated lever responding included methamphetamine, ketamine, the endogenous imidazoline ligand agmatine, the monoamine oxidase (MAO) inhibitor harmane, the α2-adrenoceptor agonist clonidine, the μ-opioid receptor agonists morphine and methadone, and the selective I2 receptor ligands BU224 and 2-BFI. The α1 adrenoceptor antagonist WB4101, α2 adrenoceptor antagonist yohimbine and μ-opioid receptor antagonist naltrexone failed to alter the stimulus effects of CR4056. Together, these results show that CR4056 can serve as a discriminative stimulus in rats, which demonstrates high pharmacological specificity and appears to be mediated by imidazoline I2 receptors.
Collapse
Affiliation(s)
- Yanyan Qiu
- 1] Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA [2] Department of Physiology, School of Basic Medical Sciences, Wuhan University, Hubei, China
| | - Xiao-Hua He
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Hubei, China
| | - Yanan Zhang
- Research Triangle Institute, Research Triangle Park, NC, USA
| | - Jun-Xu Li
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| |
Collapse
|
30
|
Min JW, Peng BW, He X, Zhang Y, Li JX. Gender difference in epileptogenic effects of 2-BFI and BU224 in mice. Eur J Pharmacol 2013; 718:81-6. [PMID: 24055191 DOI: 10.1016/j.ejphar.2013.09.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 08/28/2013] [Accepted: 09/04/2013] [Indexed: 10/26/2022]
Abstract
Imidazoline I2 receptors are involved in pain modulation and psychiatric disorders and its ligands may represent a new therapeutic strategy against pain and depression. In particular, 2-BFI and BU224 are the two most widely studied I2 receptor ligands and have antinociceptive and antidepressant-like activities in rodents. However, little is known of the toxicological effects and potential gender differences of these I2 receptor ligands. This study examined the epileptogenic activities of 2-BFI and BU224 in male and female mice and also examined their underlying receptor mechanisms. 2-BFI (10-40 mg/kg, i.p.) and BU224 (10-40 mg/kg) produced epileptic seizures in a dose-related manner, as did the epileptogenic agent, pentylenetetrazole (PTZ, 15-60 mg/kg). However, female mice were significantly more sensitive than male mice in all the measures. The commonly used I2 receptor antagonist, idazoxan (10mg/kg), did not block the onset and magnitude of the epileptic seizures or lethality induced by 2-BFI and BU224. When studied in combination, PTZ potentiated the epileptogenic effect of 2-BFI and BU224. The lack of antagonism by idazoxan of the epileptogenic activities of 2-BFI and BU224 suggests that the epileptogenic effects of 2-BFI and BU224 are mediated by non-imidazoline I2 receptors and that I2 receptors remain a viable therapeutic target for neurological disorders such as pain.
Collapse
Affiliation(s)
- Jia-Wei Min
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, 185 Donghu Road, Wuhan, Hubei 430071, PR China
| | | | | | | | | |
Collapse
|
31
|
Thorn DA, An XF, Zhang Y, Pigini M, Li JX. Characterization of the hypothermic effects of imidazoline I₂ receptor agonists in rats. Br J Pharmacol 2012; 166:1936-45. [PMID: 22324428 DOI: 10.1111/j.1476-5381.2012.01894.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Imidazoline I(2) receptors have been implicated in several CNS disorders. Although several I(2) receptor agonists have been described, no simple and sensitive in vivo bioassay is available for studying I(2) receptor ligands. This study examined I(2) receptor agonist-induced hypothermia as a functional in vivo assay of I(2) receptor agonism. EXPERIMENTAL APPROACH Different groups of rats were used to examine the effects of I(2) receptor agonists on the rectal temperature and locomotion. The pharmacological mechanisms were investigated by combining I(2) receptor ligands and different antagonists. KEY RESULTS All the selective I(2) receptor agonists examined (2-BFI, diphenyzoline, phenyzoline, CR4056, tracizoline, BU224 and S22687, 3.2-56 mg·kg(-1) , i.p.) dose-dependently and markedly decreased the rectal temperature (hypothermia) in rats, with varied duration of action. Pharmacological mechanism of the observed hypothermia was studied by combining the I(2) receptor agonists (2-BFI, BU224, tracizoline and diphenyzoline) with imidazoline I(2 ) receptor/ α(2) adrenoceptor antagonist idazoxan, selective I(1) receptor antagonist efaroxan, α(2) adrenoceptor antagonist/5-HT(1A) receptor agonist yohimbine. Idazoxan but not yohimbine or efaroxan attenuated the hypothermic effects of 2-BFI, BU224, tracizoline and diphenyzoline, supporting the I(2) receptor mechanism. In contrast, both idazoxan and yohimbine attenuated hypothermia induced by the α(2) adrenoceptor agonist clonidine. Among all the I(2) receptor agonists studied, only S22687 markedly increased the locomotor activity in rats. CONCLUSIONS AND IMPLICATIONS Imidazoline I(2) receptor agonists can produce hypothermic effects, which are primarily mediated by I(2) receptors. These data suggest that I(2) receptor agonist-induced hypothermia is a simple and sensitive in vivo assay for studying I(2) receptor ligands.
Collapse
Affiliation(s)
- David A Thorn
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo, the State University of New York, Buffalo, NY, USA
| | | | | | | | | |
Collapse
|
32
|
Meregalli C, Ceresa C, Canta A, Carozzi VA, Chiorazzi A, Sala B, Oggioni N, Lanza M, Letari O, Ferrari F, Avezza F, Marmiroli P, Caselli G, Cavaletti G. CR4056, a new analgesic I2 ligand, is highly effective against bortezomib-induced painful neuropathy in rats. J Pain Res 2012; 5:151-67. [PMID: 22792002 PMCID: PMC3392714 DOI: 10.2147/jpr.s32122] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Although bortezomib (BTZ) is the frontline treatment for multiple myeloma, its clinical use is limited by the occurrence of painful peripheral neuropathy, whose treatment is still an unmet clinical need. Previous studies have shown chronic BTZ administration (0.20 mg/kg intravenously three times a week for 8 weeks) to female Wistar rats induced a peripheral neuropathy similar to that observed in humans. In this animal model of BTZ-induced neurotoxicity, the present authors evaluated the efficacy of CR4056, a novel I2 ligand endowed with a remarkable efficacy in several animal pain models. CR4056 was administered in a wide range of doses (0.6-60 mg/kg by gavage every day for 2-3 weeks) in comparison with buprenorphine (Bupre) (28.8 μg/kg subcutaneously every day for 2 weeks) and gabapentin (Gaba) (100 mg/kg by gavage every day for 3 weeks). Chronic administration of BTZ reduced nerve conduction velocity and induced allodynia. CR4056, Bupre, or Gaba did not affect the impaired nerve conduction velocity. Conversely, CR4056 dose-dependently reversed BTZ-induced allodynia (minimum effective dose 0.6 mg/kg). The optimal dose found, 6 mg/kg, provided a constant pain relief throughout the treatment period and without rebound after suspension, being effective when coadministered with BTZ, starting before or after allodynia was established, or when administered alone after BTZ cessation. A certain degree of tolerance was seen after 7 days of administration, but only at the highest doses (20 and 60 mg/kg). Bupre was effective only acutely, since tolerance was evident from the fourth day onwards. Gaba showed a significant activity only at the fourth day of treatment. CR4056, over the range of concentrations of 3-30 μM, was unable to hinder BTZ cytotoxicity on several tumor cell lines, which could indicate that this substance does not directly interfere with BTZ antitumor activity. Therefore, CR4056 could represent a new treatment option for BTZ-induced neuropathic pain.
Collapse
Affiliation(s)
- Cristina Meregalli
- Department of Neuroscience and Biomedical Technologies, University of Milan-Bicocca
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|