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Melanocortin-4 receptor signaling in the central amygdala mediates chronic inflammatory pain effects on nociception. Neuropharmacology 2022; 210:109032. [PMID: 35304172 DOI: 10.1016/j.neuropharm.2022.109032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/22/2022] [Accepted: 03/12/2022] [Indexed: 11/24/2022]
Abstract
Chronic inflammatory pain represents one of the largest subsets of chronic pain diagnoses, which affect nearly a quarter of individuals in the United States and cost nearly $600 billion dollars annually. Chronic pain leads to persistent sensory hypersensitivities, as well as emotional and cognitive disturbances. Evidence suggests that melanocortin 4 receptors (MC4Rs) mediate pain-signaling and pain-like behaviors via actions at various nodes in the pain-neural axis, but the field lacks a complete understanding of the potential role of MC4Rs in chronic inflammatory pain in males and females. The central amygdala (CeA) expresses high quantities of MC4R and receives pain-related information from the periphery, and in vivo CeA manipulations alter nociceptive behavior in pain-naïve and in animals with chronic pain. Here, we tested the hypothesis that MC4Rs in the CeA modulate thermal nociception and mechanical sensitivity, as well as pain avoidance, in male and female Wistar rats, using a model of chronic inflammatory pain (Complete Freud's Adjuvant; CFA). First, we report that CFA produces long-lasting hyperalgesia in adult male and female Wistar rats, and long-lasting pain avoidance in male Wistar rats. Second, we report that MC4R antagonism in the CeA reduces thermal nociception and mechanical sensitivity in male and female Wistar rats treated with CFA. Finally, we report that MC4R antagonism in the CeA reduces pain avoidance in male, and that this effect is not due to drug effects on locomotor activity. Our results indicate that a model of chronic inflammatory pain produces long-lasting increases in pain-like behaviors in adult male and female Wistar rats, and that antagonism of MC4Rs in the CeA reverses those effects.
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Piotrowska A, Starnowska-Sokół J, Makuch W, Mika J, Witkowska E, Tymecka D, Ignaczak A, Wilenska B, Misicka A, Przewłocka B. Novel bifunctional hybrid compounds designed to enhance the effects of opioids and antagonize the pronociceptive effects of nonopioid peptides as potent analgesics in a rat model of neuropathic pain. Pain 2021; 162:432-445. [PMID: 32826750 PMCID: PMC7808367 DOI: 10.1097/j.pain.0000000000002045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/20/2020] [Accepted: 07/29/2020] [Indexed: 12/27/2022]
Abstract
ABSTRACT The purpose of our work was to determine the role of nonopioid peptides derived from opioid prohormones in sensory hypersensitivity characteristics of neuropathic pain and to propose a pharmacological approach to restore the balance of these endogenous opioid systems. Nonopioid peptides may have a pronociceptive effect and therefore contribute to less effective opioid analgesia in neuropathic pain. In our study, we used unilateral chronic constriction injury (CCI) of the sciatic nerve as a neuropathic pain model in rats. We demonstrated the pronociceptive effects of proopiomelanocortin- and proenkephalin-derived nonopioid peptides assessed by von Frey and cold plate tests, 7 to 14 days after injury. The concentration of proenkephalin-derived pronociceptive peptides was increased more robustly than that of Met-enkephalin in the ipsilateral lumbar spinal cord of CCI-exposed rats, as shown by mass spectrometry, and the pronociceptive effect of one of these peptides was blocked by an antagonist of the melanocortin 4 (MC4) receptor. The above results confirm our hypothesis regarding the possibility of creating an analgesic drug for neuropathic pain based on enhancing opioid activity and blocking the pronociceptive effect of nonopioid peptides. We designed and synthesized bifunctional hybrids composed of opioid (OP) receptor agonist and MC4 receptor antagonist (OP-linker-MC4). Moreover, we demonstrated that they have potent and long-lasting antinociceptive effects after a single administration and a delayed development of tolerance compared with morphine after repeated intrathecal administration to rats subjected to CCI. We conclude that the bifunctional hybrids OP-linker-MC4 we propose are important prototypes of drugs for use in neuropathic pain.
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Affiliation(s)
- Anna Piotrowska
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Joanna Starnowska-Sokół
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Wioletta Makuch
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Joanna Mika
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Ewa Witkowska
- Faculty of Chemistry, Biological, and Chemistry Research Centre, University of Warsaw, Warsaw, Poland
| | - Dagmara Tymecka
- Faculty of Chemistry, Biological, and Chemistry Research Centre, University of Warsaw, Warsaw, Poland
| | - Angelika Ignaczak
- Faculty of Chemistry, Biological, and Chemistry Research Centre, University of Warsaw, Warsaw, Poland
| | - Beata Wilenska
- Faculty of Chemistry, Biological, and Chemistry Research Centre, University of Warsaw, Warsaw, Poland
| | - Aleksandra Misicka
- Faculty of Chemistry, Biological, and Chemistry Research Centre, University of Warsaw, Warsaw, Poland
| | - Barbara Przewłocka
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
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Sharfman N, Gilpin NW. The Role of Melanocortin Plasticity in Pain-Related Outcomes After Alcohol Exposure. Front Psychiatry 2021; 12:764720. [PMID: 34803772 PMCID: PMC8599269 DOI: 10.3389/fpsyt.2021.764720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/05/2021] [Indexed: 11/13/2022] Open
Abstract
The global COVID-19 pandemic has shone a light on the rates and dangers of alcohol misuse in adults and adolescents in the US and globally. Alcohol exposure during adolescence causes persistent molecular, cellular, and behavioral changes that increase the risk of alcohol use disorder (AUD) into adulthood. It is established that alcohol abuse in adulthood increases the likelihood of pain hypersensitivity and the genesis of chronic pain, and humans report drinking alcohol to relieve pain symptoms. However, the longitudinal effects of alcohol exposure on pain and the underlying CNS signaling that mediates it are understudied. Specific brain regions mediate pain effects, alcohol effects, and pain-alcohol interactions, and neural signaling in those brain regions is modulated by neuropeptides. The CNS melanocortin system is sensitive to alcohol and modulates pain sensitivity, but this system is understudied in the context of pain-alcohol interactions. In this review, we focus on the role of melanocortin signaling in brain regions sensitive to alcohol and pain, in particular the amygdala. We also discuss interactions of melanocortins with other peptide systems, including the opioid system, as potential mediators of pain-alcohol interactions. Therapeutic strategies that target the melanocortin system may mitigate the negative consequences of alcohol misuse during adolescence and/or adulthood, including effects on pain-related outcomes.
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Affiliation(s)
- Nathan Sharfman
- Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Nicholas W Gilpin
- Department of Physiology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, United States.,Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, United States.,Alcohol and Drug Abuse Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, United States.,Southeast Louisiana VA Healthcare System (SLVHCS), New Orleans, LA, United States
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Starnowska-Sokół J, Piotrowska A, Bogacka J, Makuch W, Mika J, Witkowska E, Godlewska M, Osiejuk J, Gątarz S, Misicka A, Przewłocka B. Novel hybrid compounds, opioid agonist+melanocortin 4 receptor antagonist, as efficient analgesics in mouse chronic constriction injury model of neuropathic pain. Neuropharmacology 2020; 178:108232. [PMID: 32750445 DOI: 10.1016/j.neuropharm.2020.108232] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/24/2020] [Accepted: 07/06/2020] [Indexed: 12/30/2022]
Abstract
When the nerve tissue is injured, endogenous agonist of melanocortin type 4 (MC4) receptor, α-MSH, exerts tonic pronociceptive action in the central nervous system, contributing to sustaining the neuropathic pain state and counteracting the analgesic effects of exogenous opioids. With the intent of enhancing opioid analgesia in neuropathy by blocking the MC4 activation, so-called parent compounds (opioid agonist, MC4 antagonist) were joined together using various linkers to create novel bifunctional hybrid compounds. Analgesic action of four hybrids was tested after intrathecal (i.t.) administration in mouse models of acute and neuropathic pain (chronic constriction injury model, CCI). Under nerve injury conditions, one of the hybrids, UW3, induced analgesia in 1500 times lower i.t. dose than the opioid parent (ED50: 0.0002 nmol for the hybrid, 0.3 nmol for the opioid parent) and in an over 16000 times lower dose than the MC4 parent (ED50: 3.33 nmol) as measured by the von Frey test. Two selected hybrids were tested for analgesic properties in CCI mice after intravenous (i.v.) and intraperitoneal (i.p.) administration. Opioid receptor antagonists and MC4 receptor agonists diminished the analgesic action of these two hybrids studied, though the extent of this effect differed between the hybrids; this suggests that linker is of key importance here. Further results indicate a significant advantage of hybrid compounds over the physical mixture of individual pharmacophores in their analgesic effect. All this evidence justifies the idea of synthesizing a bifunctional opioid agonist-linker-MC4 antagonist compound, as such structure may bring important benefits in neuropathic pain treatment.
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Affiliation(s)
- Joanna Starnowska-Sokół
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Anna Piotrowska
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Joanna Bogacka
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Wioletta Makuch
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Joanna Mika
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland
| | - Ewa Witkowska
- University of Warsaw, Faculty of Chemistry, Biological and Chemistry Research Centre, Warsaw, Poland
| | - Magda Godlewska
- University of Warsaw, Faculty of Chemistry, Biological and Chemistry Research Centre, Warsaw, Poland
| | - Jowita Osiejuk
- University of Warsaw, Faculty of Chemistry, Biological and Chemistry Research Centre, Warsaw, Poland
| | - Sandra Gątarz
- University of Warsaw, Faculty of Chemistry, Biological and Chemistry Research Centre, Warsaw, Poland
| | - Aleksandra Misicka
- University of Warsaw, Faculty of Chemistry, Biological and Chemistry Research Centre, Warsaw, Poland
| | - Barbara Przewłocka
- Maj Institute of Pharmacology, Polish Academy of Sciences, Department of Pain Pharmacology, Krakow, Poland.
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Adank DN, Lunzer MM, Lensing CJ, Wilber SL, Gancarz AM, Haskell-Luevano C. Comparative in Vivo Investigation of Intrathecal and Intracerebroventricular Administration with Melanocortin Ligands MTII and AGRP into Mice. ACS Chem Neurosci 2018; 9:320-327. [PMID: 28968061 PMCID: PMC5821609 DOI: 10.1021/acschemneuro.7b00330] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Central administration of melanocortin ligands has been used as a critical technique to study energy homeostasis. While intracerebroventricular (ICV) injection is the most commonly used method during these investigations, intrathecal (IT) injection can be equally efficacious for the central delivery of ligands. Importantly, intrathecal administration can optimize exploration of melanocortin receptors in the spinal cord. Herein, we investigate comparative IT and ICV administration of two melanocortin ligands, the synthetic MTII (Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH2) MC4R agonist and agouti-related peptide [AGRP(87-132)] MC4R inverse agonist/antagonist, on the same batch of age-matched mice in TSE metabolic cages undergoing a nocturnal satiated paradigm. To our knowledge, this is the first study to test how central administration of these ligands directly to the spinal cord affects energy homeostasis. Results showed, as expected, that MTII IT administration caused a decrease in food and water intake and an overall negative energy balance without affecting activity. As anticipated, IT administration of AGRP caused weight gain, increase of food/water intake, and increase respiratory exchange ratio (RER). Unexpectantly, the prolonged activity of AGRP was notably shorter (2 days) compared to mice given ICV injections of the same concentrations in previous studies (7 days or more).1-4 It appears that IT administration results in a more sensitive response that may be a good approach for testing synthetic compound potency values ranging in nanomolar to high micromolar in vitro EC50 values. Indeed, our investigation reveals that the spine influences a different melanocortin response compared to the brain for the AGRP ligand. This study indicates that IT administration can be a useful technique for future metabolic studies using melanocortin ligands and highlights the importance of exploring the role of melanocortin receptors in the spinal cord.
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MESH Headings
- Agouti-Related Protein/administration & dosage
- Animals
- Body Weight/drug effects
- Catheters, Indwelling
- Cross-Over Studies
- Eating/drug effects
- Homeostasis/drug effects
- Injections, Intraventricular
- Injections, Spinal
- Male
- Mice, 129 Strain
- Mice, Inbred C57BL
- Peptide Fragments/administration & dosage
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/metabolism
- Time Factors
- alpha-MSH/administration & dosage
- alpha-MSH/analogs & derivatives
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Affiliation(s)
- Danielle N. Adank
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Mary M. Lunzer
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Cody J. Lensing
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Stacey L. Wilber
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Amy M. Gancarz
- Department of Psychology, California State University Bakersfield, Bakersfield, CA 93311, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
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Graebner AK, Iyer M, Carter ME. Understanding how discrete populations of hypothalamic neurons orchestrate complicated behavioral states. Front Syst Neurosci 2015; 9:111. [PMID: 26300745 PMCID: PMC4523943 DOI: 10.3389/fnsys.2015.00111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 07/16/2015] [Indexed: 01/01/2023] Open
Abstract
A major question in systems neuroscience is how a single population of neurons can interact with the rest of the brain to orchestrate complex behavioral states. The hypothalamus contains many such discrete neuronal populations that individually regulate arousal, feeding, and drinking. For example, hypothalamic neurons that express hypocretin (Hcrt) neuropeptides can sense homeostatic and metabolic factors affecting wakefulness and orchestrate organismal arousal. Neurons that express agouti-related protein (AgRP) can sense the metabolic needs of the body and orchestrate a state of hunger. The organum vasculosum of the lamina terminalis (OVLT) can detect the hypertonicity of blood and orchestrate a state of thirst. Each hypothalamic population is sufficient to generate complicated behavioral states through the combined efforts of distinct efferent projections. The principal challenge to understanding these brain systems is therefore to determine the individual roles of each downstream projection for each behavioral state. In recent years, the development and application of temporally precise, genetically encoded tools has greatly improved our understanding of the structure and function of these neural systems. This review will survey recent advances in our understanding of how these individual hypothalamic populations can orchestrate complicated behavioral states due to the combined efforts of individual downstream projections.
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Affiliation(s)
- Allison K Graebner
- Program in Neuroscience, Department of Biology, Williams College Williamstown, MA, USA
| | - Manasi Iyer
- Program in Neuroscience, Department of Biology, Williams College Williamstown, MA, USA
| | - Matthew E Carter
- Program in Neuroscience, Department of Biology, Williams College Williamstown, MA, USA
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Caruso V, Lagerström MC, Olszewski PK, Fredriksson R, Schiöth HB. Synaptic changes induced by melanocortin signalling. Nat Rev Neurosci 2014; 15:98-110. [PMID: 24588018 DOI: 10.1038/nrn3657] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The melanocortin system has a well-established role in the regulation of energy homeostasis, but there is growing evidence of its involvement in memory, nociception, mood disorders and addiction. In this Review, we focus on the role of the melanocortin 4 receptor and provide an integrative view of the molecular mechanisms that lead to melanocortin-induced changes in synaptic plasticity within these diverse physiological systems. We also highlight the importance of melanocortin peptides and receptors in chronic pain syndromes, memory impairments, depression and drug abuse, and the possibility of targeting them for therapeutic purposes.
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Abdallah K, Artola A, Monconduit L, Dallel R, Luccarini P. Bilateral descending hypothalamic projections to the spinal trigeminal nucleus caudalis in rats. PLoS One 2013; 8:e73022. [PMID: 23951340 PMCID: PMC3737186 DOI: 10.1371/journal.pone.0073022] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 07/17/2013] [Indexed: 11/25/2022] Open
Abstract
Several lines of evidence suggest that the hypothalamus is involved in trigeminal pain processing. However, the organization of descending hypothalamic projections to the spinal trigeminal nucleus caudalis (Sp5C) remains poorly understood. Microinjections of the retrograde tracer, fluorogold (FG), into the Sp5C, in rats, reveal that five hypothalamic nuclei project to the Sp5C: the paraventricular nucleus, the lateral hypothalamic area, the perifornical hypothalamic area, the A11 nucleus and the retrochiasmatic area. Descending hypothalamic projections to the Sp5C are bilateral, except those from the paraventricular nucleus which exhibit a clear ipsilateral predominance. Moreover, the density of retrogradely FG-labeled neurons in the hypothalamus varies according to the dorso-ventral localization of the Sp5C injection site. There are much more labeled neurons after injections into the ventrolateral part of the Sp5C (where ophthalmic afferents project) than after injections into its dorsomedial or intermediate parts (where mandibular and maxillary afferents, respectively, project). These results demonstrate that the organization of descending hypothalamic projections to the spinal dorsal horn and Sp5C are different. Whereas the former are ipsilateral, the latter are bilateral. Moreover, hypothalamic projections to the Sp5C display somatotopy, suggesting that these projections are preferentially involved in the processing of meningeal and cutaneous inputs from the ophthalmic branch of the trigeminal nerve in rats. Therefore, our results suggest that the control of trigeminal and spinal dorsal horn processing of nociceptive information by hypothalamic neurons is different and raise the question of the role of bilateral, rather than unilateral, hypothalamic control.
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Affiliation(s)
- Khaled Abdallah
- Clermont Université, Université d’Auvergne, NEURO-DOL: Trigeminal Pain and Migraine, BP 10448, Clermont-Ferrand; Inserm, U1107, Clermont-Ferrand, France
| | - Alain Artola
- Clermont Université, Université d’Auvergne, NEURO-DOL: Trigeminal Pain and Migraine, BP 10448, Clermont-Ferrand; Inserm, U1107, Clermont-Ferrand, France
| | - Lénaic Monconduit
- Clermont Université, Université d’Auvergne, NEURO-DOL: Trigeminal Pain and Migraine, BP 10448, Clermont-Ferrand; Inserm, U1107, Clermont-Ferrand, France
| | - Radhouane Dallel
- Clermont Université, Université d’Auvergne, NEURO-DOL: Trigeminal Pain and Migraine, BP 10448, Clermont-Ferrand; Inserm, U1107, Clermont-Ferrand, France
- * E-mail: (RD) (PL)
| | - Philippe Luccarini
- Clermont Université, Université d’Auvergne, NEURO-DOL: Trigeminal Pain and Migraine, BP 10448, Clermont-Ferrand; Inserm, U1107, Clermont-Ferrand, France
- * E-mail: (RD) (PL)
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9
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Neuronostatin induces hyperalgesia in formalin test in mice. Neurosci Lett 2012; 506:126-30. [DOI: 10.1016/j.neulet.2011.10.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 10/24/2011] [Accepted: 10/25/2011] [Indexed: 11/23/2022]
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10
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Involvement of the melanocortin-1 receptor in acute pain and pain of inflammatory but not neuropathic origin. PLoS One 2010; 5:e12498. [PMID: 20856883 PMCID: PMC2938350 DOI: 10.1371/journal.pone.0012498] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 08/06/2010] [Indexed: 01/22/2023] Open
Abstract
Background Response to painful stimuli is susceptible to genetic variation. Numerous loci have been identified which contribute to this variation, one of which, MC1R, is better known as a gene involved in mammalian hair colour. MC1R is a G protein-coupled receptor expressed in melanocytes and elsewhere and mice lacking MC1R have yellow hair, whilst humans with variant MC1R protein have red hair. Previous work has found differences in acute pain perception, and response to analgesia in mice and humans with mutations or variants in MC1R. Methodology and Principal Findings We have tested responses to noxious and non-noxious stimuli in mutant mice which lack MC1R, or which overexpress an endogenous antagonist of the receptor, as well as controls. We have also examined the response of these mice to inflammatory pain, assessing the hyperalgesia and allodynia associated with persistent inflammation, and their response to neuropathic pain. Finally we tested by a paired preference paradigm their aversion to oral administration of capsaicin, which activates the noxious heat receptor TRPV1. Female mice lacking MC1R showed increased tolerance to noxious heat and no alteration in their response to non-noxious mechanical stimuli. MC1R mutant females, and females overexpressing the endogenous MC1R antagonist, agouti signalling protein, had a reduced formalin-induced inflammatory pain response, and a delayed development of inflammation-induced hyperalgesia and allodynia. In addition they had a decreased aversion to capsaicin at moderate concentrations. Male mutant mice showed no difference from their respective controls. Mice of either sex did not show any effect of mutant genotype on neuropathic pain. Conclusions We demonstrate a sex-specific role for MC1R in acute noxious thermal responses and pain of inflammatory origin.
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Lee YS, Fernandes S, Kulkarani V, Mayorov A, Davis P, Ma SW, Brown K, Gillies RJ, Lai J, Porreca F, Hruby VJ. Design and synthesis of trivalent ligands targeting opioid, cholecystokinin, and melanocortin receptors for the treatment of pain. Bioorg Med Chem Lett 2010; 20:4080-4. [PMID: 20547453 DOI: 10.1016/j.bmcl.2010.05.078] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 05/18/2010] [Accepted: 05/19/2010] [Indexed: 11/29/2022]
Abstract
It has been known that co-administration of morphine with either cholecystokinin (CCK) receptor or melanocortin (MC) receptor antagonists enhance morphine's analgesic efficacy by reducing serious side effects such as tolerance and addiction. Considering these synergistic effects, we have designed trivalent ligands in which all three different pharmacophores for opioid, CCK, and MC receptors are combined in such a way as to conserve their own topographical pharmacophore structures. These ligands, excluding the cyclic compound, were synthesized by solid phase synthesis using Rink-amide resin under microwave assistance in very high yields. These trivalent ligands bind to their respective receptors well demonstrating that the topographical pharmacophore structures for the three receptors were retained for receptor binding. Ligand 10 was a lead compound to show the best biological activities at all three receptors.
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Affiliation(s)
- Yeon Sun Lee
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
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12
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Lee YS, Agnes RS, Cain JP, Kulkarni V, Cai M, Salibay C, Ciano K, Petrov R, Mayorov A, Vagner J, Trivedi D, Davis P, Ma SW, Lai J, Porreca F, Vardanyan R, Hruby VJ. Opioid and melanocortin receptors: do they have overlapping pharmacophores? Biopolymers 2008; 90:433-8. [PMID: 17657709 PMCID: PMC2693099 DOI: 10.1002/bip.20814] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have identified compound 1 as a novel ligand for opioid and melanocortin (MC) receptors, which is derived from the overlapping of a well known structure for the delta opioid receptor, 2,6-dimethyltyrosine (Dmt)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (Tic), and a small molecule for the MC receptor, Tic-DPhe(p-Cl)-piperidin-4-yl-N-phenyl-propionamide. Ligand 1 showed that there is an overlapping pharmacophore between opioid and MC receptors through the Tic residue. The ligand displayed high biological activities at the delta opioid receptor (Ki = 0.38 nM in binding assay, EC(50) = 0.48 nM in GTP-gamma-S binding assay, IC(50) = 74 nM in MVD) as an agonist instead of an antagonist and showed selective binding affinity (IC(50) = 2.3 muM) at the MC-3 receptor rather than at the MC-5 receptor. A study of the structure-activity relationships demonstrated that the residues in positions 2, 3, and the C-terminus act as a pharmacophore for the MC receptors, and the residues in positions 1 and 2 act as a pharmacophore for the opioid receptors. Thus, this structural construct can be used to prepare chimeric structures with adjacent or overlapping pharmacophores for opioid and MC receptors.
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Affiliation(s)
- Yeon Sun Lee
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - Richard S. Agnes
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - James P. Cain
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - Vinod Kulkarni
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - Minying Cai
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | | | - Kathy Ciano
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - Ravil Petrov
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | | | - Josef Vagner
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - Dev Trivedi
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - Peg Davis
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Shou-wu Ma
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Josephine Lai
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Frank Porreca
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Ruben Vardanyan
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
| | - Victor J. Hruby
- Department of Chemistry, University of Arizona, Tucson, AZ 85721
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Agouti-related peptide and MC3/4 receptor agonists both inhibit excitatory hypothalamic ventromedial nucleus neurons. J Neurosci 2008; 28:5433-49. [PMID: 18495877 DOI: 10.1523/jneurosci.0749-08.2008] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Anorexigenic melanocortins decrease food intake by activating MC3/MC4 receptors (MC3/4R); the prevailing view is that the orexigenic neuropeptide agouti-related peptide (AgRP) exerts the opposite action by acting as an antagonist at MC3/MC4 receptors. A total of 370 hypothalamic ventromedial nucleus (VMH) glutamatergic neurons was studied using whole-cell recording in hypothalamic slices from a novel mouse expressing green fluorescent protein (GFP) under control of the vesicular glutamate transporter 2 (vGluT2) promoter. Massive numbers of GFP-expressing VMH dendrites extended out of the core of the nucleus into the surrounding cell-poor shell. VMH dendrites received frequent appositions from AgRP-immunoreactive axons in the shell of the nucleus, but not the core, suggesting that AgRP may influence target VMH neurons. alpha-MSH, melanotan II (MTII), and selective MC3R or MC4R agonists were all inhibitory, reducing the spontaneous firing rate and hyperpolarizing vGluT2 neurons. The MC3/4R antagonist SHU9119 was excitatory. Unexpectedly, AgRP did not attenuate MTII actions on these neurons; instead, these two compounds showed an additive inhibitory effect. In the absence of synaptic activity, no hyperpolarization or change in input resistance was evoked by either MTII or AgRP, suggesting indirect actions. Consistent with this view, MTII increased the frequency of spontaneous and miniature IPSCs. In contrast, the mechanism of AgRP inhibition was dependent on presynaptic inhibition of EPSCs mediated by G(i)/G(o)-proteins, and was attenuated by pertussis toxin and NF023, inconsistent with mediation by G(s)-proteins associated with MC receptors. Together, our data suggest that the mechanism of AgRP actions on these excitatory VMH cells appears to be independent of the actions of melanocortins on MC receptors.
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Chen C. Recent progress toward nonpeptide ligands for the melanocortin-4 receptor. PROGRESS IN MEDICINAL CHEMISTRY 2007; 45:111-67. [PMID: 17280903 DOI: 10.1016/s0079-6468(06)45503-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- Chen Chen
- Department of Medicinal Chemistry, Neurocrine Biosciences, Inc., 12700 El Camino Real, San Diego, CA 92130, USA
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15
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Starowicz K, Obara I, Przewłocki R, Przewlocka B. Inhibition of morphine tolerance by spinal melanocortin receptor blockade. Pain 2005; 117:401-411. [PMID: 16153779 DOI: 10.1016/j.pain.2005.07.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 06/14/2005] [Accepted: 07/12/2005] [Indexed: 11/26/2022]
Abstract
Chronic use of morphine is accompanied by the development of morphine tolerance, which is one of the major problems associated with opiate treatment. Possible modulation of opioid effects by melanocortin receptor ligands has been recently demonstrated. Therefore, we investigated the influence of repeated intrathecal injection of a melanocortin receptor antagonist (SHU9119, JKC-363) on the development of morphine tolerance as measured by tail-flick test. It was also examined whether a single i.t. SHU9119 and JKC-363 administration could counteract the loss of analgesic potency of morphine in morphine tolerant rats. We examined also the influence of chronic morphine administration on mu-opioid receptor (MOR) and melanocortin 4 receptor (MC4-R) mRNAs in the rat spinal cord and dorsal root ganglia (DRG) during morphine tolerance. Morphine treatment (10mg/kg, i.p. twice daily) over 8 days induced tolerance as reflected by a significant reduction of withdrawal latency from 181 to 25% above baseline in the tail-flick test. Repeated co-administration of morphine and SHU9119 or JKC-363, significantly prevented the development of morphine tolerance. A single administration of an MC4-R antagonist restored morphine analgesic potency in morphine tolerant rats. Using RT-PCR we demonstrated no changes in the spinal cord but there was a decrease in MOR and increase in MC4-R gene expression in the DRG of rats tolerant to morphine. These results suggest that MC4-R may be involved in the mechanisms of opioid tolerance and antagonists of this receptor may be a possible new target in the search for strategies preventing the development of opioid tolerance.
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MESH Headings
- Analysis of Variance
- Animals
- Area Under Curve
- Behavior, Animal
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Drug Interactions
- Drug Tolerance/physiology
- Gene Expression Regulation/drug effects
- Male
- Melanocyte-Stimulating Hormones/pharmacology
- Morphine/adverse effects
- Pain Measurement/drug effects
- Pain Measurement/instrumentation
- Peptides, Cyclic/pharmacology
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Reaction Time/drug effects
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptors, Melanocortin/antagonists & inhibitors
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Time Factors
- beta-MSH/pharmacology
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Affiliation(s)
- Katarzyna Starowicz
- Department of Molecular Neuropharmacology, Institute of Pharmacology, 12 Smetna str, 31-343 Cracow, Poland Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 4 Ks. Trojdena str, 02-109 Warsaw, Poland
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16
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Tran JA, Pontillo J, Arellano M, Fleck BA, Tucci FC, Marinkovic D, Chen CW, Saunders J, Foster AC, Chen C. Structure–activity relationship of a series of cyclohexylpiperidines bearing an amide side chain as antagonists of the human melanocortin-4 receptor. Bioorg Med Chem Lett 2005; 15:3434-8. [PMID: 15950470 DOI: 10.1016/j.bmcl.2005.05.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 04/29/2005] [Accepted: 05/03/2005] [Indexed: 11/16/2022]
Abstract
A series of cyclohexylpiperazines was synthesized as potent and selective antagonists of the human MC4 receptor. Compound 14t displayed binding affinity (Ki) of 4.2 and 1100 nM at MC4R and MC3R, respectively.
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Affiliation(s)
- Joseph A Tran
- Department of Medicinal Chemistry, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, CA 92130, USA
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17
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Ercil NE, Galici R, Kesterson RA. HS014, a selective melanocortin-4 (MC4) receptor antagonist, modulates the behavioral effects of morphine in mice. Psychopharmacology (Berl) 2005; 180:279-85. [PMID: 15719225 DOI: 10.1007/s00213-005-2166-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2004] [Accepted: 12/23/2004] [Indexed: 11/28/2022]
Abstract
RATIONALE Melanocortin and opioid systems regulate feeding as well as other behaviors; however, the relationship between the two systems is not yet defined. Since agonist-induced stimulation of melanocortin receptors blocks the behavioral effects of mu opioid receptor agonists, and melanocortin-4 (MC4) receptors and mu opioid receptors share a similar anatomical distribution in the central nervous system, MC4 receptor blockade may increase opioid responsiveness. OBJECTIVES The goal of this study was to test the hypothesis that blockade of MC4 receptors increases the behavioral effects of morphine. METHODS The effects of HS014 (0.0032, 0.032, and 1 nmol, i.c.v.), a selective MC4 antagonist, on morphine-induced (3.2, 10, and 32 mg/kg, i.p.) locomotor activity (measured in the open field for 15 min) and antinociception (measured in the hot plate at 55 degrees C) were assessed in C57Bl/6 mice. In addition, the effects of morphine were evaluated in A(y) mice, a genetic model for MC4 receptor blockade. RESULTS The dose-effect curve of morphine for locomotor activity was shifted downwards in C57Bl/6 mice pretreated with HS014 and in A(y) mice. The dose-effect curve of morphine for antinociception was shifted two- and threefold to the left in C57Bl/6 mice pretreated with HS014 and in A(y) mice, respectively. CONCLUSIONS These results indicate that blockade of MC4 receptors increases the antinociceptive effects of morphine without changing the potency of morphine for locomotor activity, suggesting that MC4 receptor antagonists may be candidate drugs that can be clinically used for the treatment of pain.
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Affiliation(s)
- N Eser Ercil
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 702 Light Hall, Nashville, TN 37232, USA
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Pontillo J, Tran JA, Markison S, Joppa M, Fleck BA, Marinkovic D, Arellano M, Tucci FC, Lanier M, Nelson J, Saunders J, Hoare SRJ, Foster AC, Chen C. A potent and selective nonpeptide antagonist of the melanocortin-4 receptor induces food intake in satiated mice. Bioorg Med Chem Lett 2005; 15:2541-6. [PMID: 15863313 DOI: 10.1016/j.bmcl.2005.03.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 03/10/2005] [Accepted: 03/15/2005] [Indexed: 10/25/2022]
Abstract
Optimization on a series of piperazinebenzylamines resulted in analogues with low nanomolar binding at the human MC4 receptor but weak affinity (Ki > 500 nM) at the MC3 receptor. Compound 14c was identified to be a potent MC4R antagonist (Ki = 3.2 nM) with a selectivity of 240-fold over MC3R. It proved to be an insurmountable antagonist in a cAMP assay. Compound 14c potently stimulated food intake in satiated mice when given by intracerebroventricular administration.
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Affiliation(s)
- Joseph Pontillo
- Department of Medicinal Chemistry, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, CA 92130, USA
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Bertorelli R, Fredduzzi S, Tarozzo G, Campanella M, Grundy R, Beltramo M, Reggiani A. Endogenous and exogenous melanocortin antagonists induce anti-allodynic effects in a model of rat neuropathic pain. Behav Brain Res 2005; 157:55-62. [PMID: 15617771 DOI: 10.1016/j.bbr.2004.06.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Revised: 06/08/2004] [Accepted: 06/09/2004] [Indexed: 11/23/2022]
Abstract
A number of studies suggest melanocortin (MC) system involvement in nociceptive modulation. Although the mechanism through which this occurs is still unknown, experimental evidence would suggest a primary role of MC4 receptors. To further investigate the implication of this MC receptor subtype in chronic pain, we have studied the effects of several MC antagonists on spinal nerve ligation-induced nociceptive behavior in rats. The intrathecal injection of synthetic antagonists with different selectivity to MC4 receptor and of an endogenous antagonist (Agouti related protein; AgRP) reduced mechanical allodynia in neuropathic rats, as measured by von Frey hair test. Treatments produced an anti-allodynic effect at the dose of 1.5 nmol (25-30% maximum possible effect, MPE, P<0.05). To further investigate the possible physiological role of AgRP in pain modulation we studied its expression in both sham and neuropathic rat spinal cord and dorsal root ganglia (DRG) by quantitative real time PCR and immunohistochemistry. AgRP was present in both spinal cord and DRG, and its expression, was unchanged in neuropathic animals. In conclusion MC4 receptor antagonists with different selectivity profile, induce anti-allodynic effects in one of the most relevant neuropathic pain model. In addition the expression of AgRP in spinal cord and DRG suggests an endogenous tonic inhibitory control on MC system activity. In pathological conditions this steady control could be insufficient to cope with an over activated MC system leading to increase in nociception. These data suggest that targeting MC4 with synthetic antagonists could restore the balance and hence reduce nociception.
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MESH Headings
- Agouti-Related Protein
- Animals
- Disease Models, Animal
- Ganglia, Spinal/metabolism
- Immunohistochemistry
- Injections, Spinal
- Intercellular Signaling Peptides and Proteins
- Male
- Pain/drug therapy
- Pain/metabolism
- Proteins/administration & dosage
- Proteins/genetics
- Proteins/metabolism
- RNA, Messenger/analysis
- Rats
- Rats, Sprague-Dawley
- Receptor, Melanocortin, Type 3/antagonists & inhibitors
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/metabolism
- Sciatic Neuropathy/drug therapy
- Sciatic Neuropathy/metabolism
- Spinal Cord/metabolism
- Spinal Nerves/drug effects
- Spinal Nerves/metabolism
- Tissue Distribution
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Affiliation(s)
- Rosalia Bertorelli
- Schering Plough Research Institute, San Raffaele Science Park, Via Olgettina, 58, 20132 Milan, Italy.
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