1
|
Gooding SW, Whistler JL. A Balancing Act: Learning from the Past to Build a Future-Focused Opioid Strategy. Annu Rev Physiol 2024; 86:1-25. [PMID: 38029388 PMCID: PMC10987332 DOI: 10.1146/annurev-physiol-042022-015914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
The harmful side effects of opioid drugs such as respiratory depression, tolerance, dependence, and abuse potential have limited the therapeutic utility of opioids for their entire clinical history. However, no previous attempt to develop effective pain drugs that substantially ameliorate these effects has succeeded, and the current opioid epidemic affirms that they are a greater hindrance to the field of pain management than ever. Recent attempts at new opioid development have sought to reduce these side effects by minimizing engagement of the regulatory protein arrestin-3 at the mu-opioid receptor, but there is significant controversy around this approach. Here, we discuss the ongoing effort to develop safer opioids and its relevant historical context. We propose a new model that reconciles results previously assumed to be in direct conflict to explain how different signaling profiles at the mu-opioid receptor contribute to opioid tolerance and dependence. Our goal is for this framework to inform the search for a new generation of lower liability opioid analgesics.
Collapse
Affiliation(s)
| | - Jennifer L Whistler
- Center for Neuroscience, University of California, Davis, California, USA;
- Department of Physiology and Membrane Biology, UC Davis School of Medicine, Davis, California, USA
| |
Collapse
|
2
|
Ochandarena NE, Niehaus JK, Tassou A, Scherrer G. Cell-type specific molecular architecture for mu opioid receptor function in pain and addiction circuits. Neuropharmacology 2023; 238:109597. [PMID: 37271281 PMCID: PMC10494323 DOI: 10.1016/j.neuropharm.2023.109597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 05/13/2023] [Indexed: 06/06/2023]
Abstract
Opioids are potent analgesics broadly used for pain management; however, they can produce dangerous side effects including addiction and respiratory depression. These harmful effects have led to an epidemic of opioid abuse and overdose deaths, creating an urgent need for the development of both safer pain medications and treatments for opioid use disorders. Both the analgesic and addictive properties of opioids are mediated by the mu opioid receptor (MOR), making resolution of the cell types and neural circuits responsible for each of the effects of opioids a critical research goal. Single-cell RNA sequencing (scRNA-seq) technology is enabling the identification of MOR-expressing cell types throughout the nervous system, creating new opportunities for mapping distinct opioid effects onto newly discovered cell types. Here, we describe molecularly defined MOR-expressing neuronal cell types throughout the peripheral and central nervous systems and their potential contributions to opioid analgesia and addiction.
Collapse
Affiliation(s)
- Nicole E Ochandarena
- Neuroscience Curriculum, Biological and Biomedical Sciences Program, The University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA; Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Jesse K Niehaus
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Adrien Tassou
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Grégory Scherrer
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; New York Stem Cell Foundation - Robertson Investigator, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
| |
Collapse
|
3
|
Fairbanks CA, Peterson CD. The opioid receptor: emergence through millennia of pharmaceutical sciences. FRONTIERS IN PAIN RESEARCH 2023; 4:960389. [PMID: 38028425 PMCID: PMC10646403 DOI: 10.3389/fpain.2023.960389] [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: 06/02/2022] [Accepted: 10/02/2023] [Indexed: 12/01/2023] Open
Abstract
Throughout history humanity has searched for an optimal approach to the use of opioids that maximizes analgesia while minimizing side effects. This review reflects upon the conceptualization of the opioid receptor and the critical role that the pharmaceutical sciences played in its revelation. Opium-containing formulations have been delivered by various routes of administration for analgesia and other therapeutic indications for millennia. The concept of a distinct site of opium action evolved as practitioners developed innovative delivery methods, such as intravenous administration, to improve therapeutic outcomes. The introduction of morphine and synthetic opioids engendered the prevalent assumption of a common opioid receptor. Through consideration of structure-activity relationships, spatial geometry, and pharmacological differences of known ligands, the idea of multiple opioid receptors emerged. By accessing the high-affinity property of naloxone, the opioid receptor was identified in central and peripheral nervous system tissue. The endogenous opioid neuropeptides were subsequently discovered. Application of mu-, delta-, and kappa- opioid receptor-selective ligands facilitated the pharmacological characterization and distinctions between the three receptors, which were later cloned and sequenced. Opioid receptor signal transduction pathways were described and attributed to specific physiological outcomes. The crystal structures of mu, delta, kappa, and nociceptin/orphanin FQ receptors bound to receptor-selective ligands have been elucidated. Comparison of these structures reveal locations of ligand binding and engagement of signal transduction pathways. Expanding knowledge regarding the structure and actions of the opioid receptor fuels contemporary strategies for driving the activity of opioid receptors toward maximizing therapeutic and minimizing adverse outcomes.
Collapse
Affiliation(s)
- Carolyn A. Fairbanks
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, United States
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, United States
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Cristina D. Peterson
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, United States
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| |
Collapse
|
4
|
Clark TP. The history and pharmacology of buprenorphine: New advances in cats. J Vet Pharmacol Ther 2022; 45 Suppl 1:S1-S30. [DOI: 10.1111/jvp.13073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 04/19/2022] [Accepted: 05/14/2022] [Indexed: 11/30/2022]
|
5
|
Singh UA, Iyengar S. The Role of the Endogenous Opioid System in the Vocal Behavior of Songbirds and Its Possible Role in Vocal Learning. Front Physiol 2022; 13:823152. [PMID: 35273519 PMCID: PMC8902293 DOI: 10.3389/fphys.2022.823152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/31/2022] [Indexed: 12/04/2022] Open
Abstract
The opioid system in the brain is responsible for processing affective states such as pain, pleasure, and reward. It consists of three main receptors, mu- (μ-ORs), delta- (δ-ORs), and kappa- (κ-ORs), and their ligands – the endogenous opioid peptides. Despite their involvement in the reward pathway, and a signaling mechanism operating in synergy with the dopaminergic system, fewer reports focus on the role of these receptors in higher cognitive processes. Whereas research on opioids is predominated by studies on their addictive properties and role in pain pathways, recent studies suggest that these receptors may be involved in learning. Rodents deficient in δ-ORs were poor at recognizing the location of novel objects in their surroundings. Furthermore, in chicken, learning to avoid beads coated with a bitter chemical from those without the coating was modulated by δ-ORs. Similarly, μ-ORs facilitate long term potentiation in hippocampal CA3 neurons in mammals, thereby having a positive impact on spatial learning. Whereas these studies have explored the role of opioid receptors on learning using reward/punishment-based paradigms, the role of these receptors in natural learning processes, such as vocal learning, are yet unexplored. In this review, we explore studies that have established the expression pattern of these receptors in different brain regions of birds, with an emphasis on songbirds which are model systems for vocal learning. We also review the role of opioid receptors in modulating the cognitive processes associated with vocalizations in birds. Finally, we discuss the role of these receptors in regulating the motivation to vocalize, and a possible role in modulating vocal learning.
Collapse
|
6
|
Exploring Pharmacological Functions of Alternatively Spliced Variants of the Mu Opioid Receptor Gene, Oprm1, via Gene-Targeted Animal Models. Int J Mol Sci 2022; 23:ijms23063010. [PMID: 35328429 PMCID: PMC8950057 DOI: 10.3390/ijms23063010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 02/01/2023] Open
Abstract
The mu opioid receptor has a distinct place in the opioid receptor family, since it mediates the actions of most opioids used clinically (e.g., morphine and fentanyl), as well as drugs of abuse (e.g., heroin). The single-copy mu opioid receptor gene, OPRM1, goes through extensive alternative pre-mRNA splicing to generate numerous splice variants that are conserved from rodents to humans. These OPRM1 splice variants can be classified into three structurally distinct types: (1) full-length 7 transmembrane (TM) carboxyl (C)-terminal variants; (2) truncated 6TM variants; and (3) single TM variants. Distinct pharmacological functions of these splice variants have been demonstrated by both in vitro and in vivo studies, particularly by using several unique gene-targeted mouse models. These studies provide new insights into our understanding of the complex actions of mu opioids with regard to OPRM1 alternative splicing. This review provides an overview of the studies that used these gene-targeted mouse models for exploring the functional importance of Oprm1 splice variants.
Collapse
|
7
|
Cox BM, Toll L. Contributions of the International Narcotics Research Conference to Opioid Research Over the Past 50 years. ADVANCES IN DRUG AND ALCOHOL RESEARCH 2022; 2:10115. [PMID: 38390618 PMCID: PMC10880772 DOI: 10.3389/adar.2022.10115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/14/2022] [Indexed: 02/24/2024]
Abstract
The International Narcotics Research Conference (INRC), founded in 1969, has been a successful forum for research into the actions of opiates, with an annual conference since 1971. Every year, scientists from around the world have congregated to present the latest data on novel opiates, opiate receptors and endogenous ligands, mechanisms of analgesic activity and unwanted side effects, etc. All the important discoveries in the opiate field were discussed, often first, at the annual INRC meeting. With an apology to important events and participants not discussed, this review presents a short history of INRC with a discussion of groundbreaking discoveries in the opiate field and the researchers who presented from the first meeting up to the present.
Collapse
Affiliation(s)
- Brian M Cox
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Lawrence Toll
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| |
Collapse
|
8
|
Bai J, Ye T, Wei YB, Yang Y, Yang HM, Lan Y. Opioid receptors modulate parallel fiber-Purkinje cell synaptic transmission in mouse cerebellum. Neurosci Lett 2021; 770:136356. [PMID: 34808268 DOI: 10.1016/j.neulet.2021.136356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 11/20/2022]
Abstract
Opioid receptors play important roles in, among others, learning and memory, emotional responses, addiction, and pain. In recent years, the cerebellum has received increasing attention for its role in non-motor functions. The Purkinje cell (PC) is the only efferent neuron in the cerebellar cortex, and receives glutamatergic synaptic inputs from the parallel fibers (PF) formed by the axons of granule cells. Studies have shown that opioid receptors are expressed during the development of cerebellar cells. However, the distribution of opioid receptors, their subtypes in cerebellar PF-PC synapses, and their effects on synaptic transmission remain unclear. To examine these questions, we used whole-cell patch clamp recordings and pharmacological methods to determine the effects of activating three different opioid receptor subtypes on synaptic transmission at PF-PC synapses. In the presence of picrotoxin, mouse cerebellar slices were perfused with agonists or blockers of different opioid receptor subtypes, and the changes in excitatory postsynaptic currents (EPSCs) were examined. Both agonists of µ-opioid receptors (MOR) and δ-opioid receptors (DOR) significantly reduced the amplitude and area under the curve of PF-PC EPSCs in a concentration-dependent manner, accompanied by an increase in the paired-pulsed ratio (PPR). These effects could be blocked by respective receptor antagonists. In contrast, no significant changes were found after the application of κ-opioid receptor (KOR) agonists. In conclusion, MOR and DOR are present at the axon terminals of PF in the mouse cerebellar cortex, whereas no or negligible amounts of KOR are found. Activation of MOR and DOR regulates PF-PC synaptic transmission via inhibition of glutamate (Glu) release in cerebellar cortex in mice. We also found that endogenous opioid peptides are present in PF-PC synapses of mouse cerebellum, which also can inhibit the release of Glu.
Collapse
Affiliation(s)
- Jin Bai
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, Jilin Province 133002, China
| | - Ting Ye
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, Jilin Province 133002, China; Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University, Yanji City, Jilin Province 133002, China
| | - Yan-Bin Wei
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, Jilin Province 133002, China
| | - Yi Yang
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, Jilin Province 133002, China
| | - He-Min Yang
- Central Laboratory, The 3rd Affiliated Hospital, Qiqihar Medical University, Qiqihar City, Heilongjiang Province 161006, China.
| | - Yan Lan
- Department of Physiology and Pathophysiology, College of Medicine, Yanbian University, Yanji City, Jilin Province 133002, China.
| |
Collapse
|
9
|
Caron A, Jane Michael N. New Horizons: Is Obesity a Disorder of Neurotransmission? J Clin Endocrinol Metab 2021; 106:e4872-e4886. [PMID: 34117881 DOI: 10.1210/clinem/dgab421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Indexed: 11/19/2022]
Abstract
Obesity is a disease of the nervous system. While some will view this statement as provocative, others will take it as obvious. Whatever our side is, the pharmacology tells us that targeting the nervous system works for promoting weight loss. It works, but at what cost? Is the nervous system a safe target for sustainable treatment of obesity? What have we learned-and unlearned-about the central control of energy balance in the last few years? Herein we provide a thought-provoking exploration of obesity as a disorder of neurotransmission. We discuss the state of knowledge on the brain pathways regulating energy homeostasis that are commonly targeted in anti-obesity therapy and explore how medications affecting neurotransmission such as atypical antipsychotics, antidepressants, and antihistamines relate to body weight. Our goal is to provide the endocrine community with a conceptual framework that will help expending our understanding of the pathophysiology of obesity, a disease of the nervous system.
Collapse
Affiliation(s)
- Alexandre Caron
- Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
- Quebec Heart and Lung Institute, Quebec City, QC, Canada
- Montreal Diabetes Research Center, Montreal, QC, Canada
| | - Natalie Jane Michael
- Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
- Quebec Heart and Lung Institute, Quebec City, QC, Canada
| |
Collapse
|
10
|
Liu S, Kang WJ, Abrimian A, Xu J, Cartegni L, Majumdar S, Hesketh P, Bekker A, Pan YX. Alternative Pre-mRNA Splicing of the Mu Opioid Receptor Gene, OPRM1: Insight into Complex Mu Opioid Actions. Biomolecules 2021; 11:biom11101525. [PMID: 34680158 PMCID: PMC8534031 DOI: 10.3390/biom11101525] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 12/03/2022] Open
Abstract
Most opioid analgesics used clinically, including morphine and fentanyl, as well as the recreational drug heroin, act primarily through the mu opioid receptor, a class A Rhodopsin-like G protein-coupled receptor (GPCR). The single-copy mu opioid receptor gene, OPRM1, undergoes extensive alternative splicing, creating multiple splice variants or isoforms via a variety of alternative splicing events. These OPRM1 splice variants can be categorized into three major types based on the receptor structure: (1) full-length 7 transmembrane (TM) C-terminal variants; (2) truncated 6TM variants; and (3) single TM variants. Increasing evidence suggests that these OPRM1 splice variants are pharmacologically important in mediating the distinct actions of various mu opioids. More importantly, the OPRM1 variants can be targeted for development of novel opioid analgesics that are potent against multiple types of pain, but devoid of many side-effects associated with traditional opiates. In this review, we provide an overview of OPRM1 alternative splicing and its functional relevance in opioid pharmacology.
Collapse
Affiliation(s)
- Shan Liu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Wen-Jia Kang
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Anna Abrimian
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Jin Xu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Luca Cartegni
- Department of Chemical Biology, Ernest Mario School of Pharmacy Rutgers University, Piscataway, NJ 08854, USA;
| | - Susruta Majumdar
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO 63110, USA;
| | - Patrick Hesketh
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Alex Bekker
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Ying-Xian Pan
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
- Correspondence: ; Tel.: +1-973-972-3213
| |
Collapse
|
11
|
Rossi GC, Bodnar RJ. Interactive Mechanisms of Supraspinal Sites of Opioid Analgesic Action: A Festschrift to Dr. Gavril W. Pasternak. Cell Mol Neurobiol 2021; 41:863-897. [PMID: 32970288 DOI: 10.1007/s10571-020-00961-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/03/2020] [Indexed: 12/30/2022]
Abstract
Almost a half century of research has elaborated the discoveries of the central mechanisms governing the analgesic responses of opiates, including their receptors, endogenous peptides, genes and their putative spinal and supraspinal sites of action. One of the central tenets of "gate-control theories of pain" was the activation of descending supraspinal sites by opiate drugs and opioid peptides thereby controlling further noxious input. This review in the Special Issue dedicated to the research of Dr. Gavril Pasternak indicates his contributions to the understanding of supraspinal mediation of opioid analgesic action within the context of the large body of work over this period. This review will examine (a) the relevant supraspinal sites mediating opioid analgesia, (b) the opioid receptor subtypes and opioid peptides involved, (c) supraspinal site analgesic interactions and their underlying neurophysiology, (d) molecular (particularly AS) tools identifying opioid receptor actions, and (e) relevant physiological variables affecting site-specific opioid analgesia. This review will build on classic initial studies, specify the contributions that Gavril Pasternak and his colleagues did in this specific area, and follow through with studies up to the present.
Collapse
Affiliation(s)
- Grace C Rossi
- Department of Psychology, C.W. Post College, Long Island University, Post Campus, Brookville, NY, USA.
| | - Richard J Bodnar
- Department of Psychology, Queens College of the City University of New York, Flushing, NY, USA
- CUNY Neuroscience Collaborative, Graduate Center, CUNY, New York, NY, USA
| |
Collapse
|
12
|
Gledhill LJ, Babey AM. Synthesis of the Mechanisms of Opioid Tolerance: Do We Still Say NO? Cell Mol Neurobiol 2021; 41:927-948. [PMID: 33704603 DOI: 10.1007/s10571-021-01065-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/12/2021] [Indexed: 10/21/2022]
Abstract
The use of morphine as a first-line agent for moderate-to-severe pain is limited by the development of analgesic tolerance. Initially opioid receptor desensitization in response to repeated stimulation, thought to underpin the establishment of tolerance, was linked to a compensatory increase in adenylate cyclase responsiveness. The subsequent demonstration of cross-talk between N-methyl-D-aspartate (NMDA) glutamate receptors and opioid receptors led to the recognition of a role for nitric oxide (NO), wherein blockade of NO synthesis could prevent tolerance developing. Investigations of the link between NO levels and opioid receptor desensitization implicated a number of events including kinase recruitment and peroxynitrite-mediated protein regulation. Recent experimental advances and the identification of new cellular constituents have expanded the potential signaling candidates to include unexpected, intermediary compounds not previously linked to this process such as zinc, histidine triad nucleotide-binding protein 1 (HINT1), micro-ribonucleic acid (mi-RNA) and regulator of G protein signaling Z (RGSZ). A further complication is a lack of consistency in the protocols used to create tolerance, with some using acute methods measured in minutes to hours and others using days. There is also an emphasis on the cellular changes that are extant only after tolerance has been established. Although a review of the literature demonstrates a lack of spatio-temporal detail, there still appears to be a pivotal role for nitric oxide, as well as both intracellular and intercellular cross-talk. The use of more consistent approaches to verify these underlying mechanism(s) could provide an avenue for targeted drug development to rescue opioid efficacy.
Collapse
Affiliation(s)
- Laura J Gledhill
- CURA Pharmacy, St. John of God Hospital, Bendigo, VIC, 3550, Australia
| | - Anna-Marie Babey
- Faculty of Medicine and Health, University of New England, Armidale, NSW, 2351, Australia.
| |
Collapse
|
13
|
Morphine produces potent antinociception, sedation, and hypothermia in humanized mice expressing human mu-opioid receptor splice variants. Pain 2021; 161:1177-1190. [PMID: 32040076 DOI: 10.1097/j.pain.0000000000001823] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Morphine is a strong painkiller acting through mu-opioid receptor (MOR). Full-length 7-transmembrane (TM) variants of MOR share similar amino acid sequences of TM domains in rodents and humans; however, interspecies differences in N- and C-terminal amino acid sequences of MOR splice variants dramatically affect the downstream signaling. Thus, it is essential to develop a mouse model that expresses human MOR splice variants for opioid pharmacological studies. We generated 2 lines of fully humanized MOR mice (hMOR; mMOR mice), line #1 and #2. The novel murine model having human OPRM1 genes and human-specific variants was examined by reverse-transcription polymerase chain reaction and the MinION nanopore sequencing. The differences in the regional distribution of MOR between wild-type and humanized MOR mice brains were detected by RNAscope and radioligand binding assay. hMOR; mMOR mice were characterized in vivo using a tail-flick, charcoal meal, open field, tail suspension, naloxone precipitation tests, and rectal temperature measurement. The data indicated that wild-type and humanized MOR mice exhibited different pharmacology of morphine, including antinociception, tolerance, sedation, and withdrawal syndromes, suggesting the presence of species difference between mouse and human MORs. Therefore, hMOR; mMOR mice could serve as a novel mouse model for pharmacogenetic studies of opioids.
Collapse
|
14
|
Hall FS, Chen Y, Resendiz-Gutierrez F. The Streetlight Effect: Reappraising the Study of Addiction in Light of the Findings of Genome-wide Association Studies. BRAIN, BEHAVIOR AND EVOLUTION 2021; 95:230-246. [PMID: 33849024 DOI: 10.1159/000516169] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/27/2021] [Indexed: 12/12/2022]
Abstract
Drug dependence has long been thought to have a genetic component. Research seeking to identify the genetic basis of addiction has gone through important transitions over its history, in part based upon the emergence of new technologies, but also as the result of changing perspectives. Early research approaches were largely dictated by available technology, with technological advancements having highly transformative effects on genetic research, but the limitations of technology also affected modes of thinking about the genetic causes of disease. This review explores these transitions in thinking about the genetic causes of addiction in terms of the "streetlight effect," which is a type of observational bias whereby people search for something only where it is easiest to search. In this way, the genes that were initially studied in the field of addiction genetics were chosen because they were the most "obvious," and formed current understanding of the biological mechanisms underlying the actions of drugs of abuse and drug dependence. The problem with this emphasis is that prior to the genomic era the vast majority of genes and proteins had yet to be identified, much less studied. This review considers how these initial choices, as well as subsequent choices that were also driven by technological limitations, shaped the study of the genetic basis of drug dependence. While genome-wide approaches overcame the initial biases regarding which genes to choose to study inherent in candidate gene studies and other approaches, genome-wide approaches necessitated other assumptions. These included additive genetic causation and limited allelic heterogeneity, which both appear to be incorrect. Thus, the next stage of advancement in this field must overcome these shortcomings through approaches that allow the examination of complex interactive effects, both gene × gene and gene × environment interactions. Techniques for these sorts of studies have recently been developed and represent the next step in our understanding of the genetic basis of drug dependence.
Collapse
Affiliation(s)
- F Scott Hall
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacology and Pharmacological Science, University of Toledo, Toledo, Ohio, USA
| | - Yu Chen
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacology and Pharmacological Science, University of Toledo, Toledo, Ohio, USA
| | - Federico Resendiz-Gutierrez
- Department of Pharmacology and Experimental Therapeutics, College of Pharmacology and Pharmacological Science, University of Toledo, Toledo, Ohio, USA
| |
Collapse
|
15
|
Abrimian A, Kraft T, Pan YX. Endogenous Opioid Peptides and Alternatively Spliced Mu Opioid Receptor Seven Transmembrane Carboxyl-Terminal Variants. Int J Mol Sci 2021; 22:ijms22073779. [PMID: 33917474 PMCID: PMC8038826 DOI: 10.3390/ijms22073779] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/02/2021] [Accepted: 04/04/2021] [Indexed: 12/20/2022] Open
Abstract
There exist three main types of endogenous opioid peptides, enkephalins, dynorphins and β-endorphin, all of which are derived from their precursors. These endogenous opioid peptides act through opioid receptors, including mu opioid receptor (MOR), delta opioid receptor (DOR) and kappa opioid receptor (KOR), and play important roles not only in analgesia, but also many other biological processes such as reward, stress response, feeding and emotion. The MOR gene, OPRM1, undergoes extensive alternative pre-mRNA splicing, generating multiple splice variants or isoforms. One type of these splice variants, the full-length 7 transmembrane (TM) Carboxyl (C)-terminal variants, has the same receptor structures but contains different intracellular C-terminal tails. The pharmacological functions of several endogenous opioid peptides through the mouse, rat and human OPRM1 7TM C-terminal variants have been considerably investigated together with various mu opioid ligands. The current review focuses on the studies of these endogenous opioid peptides and summarizes the results from early pharmacological studies, including receptor binding affinity and G protein activation, and recent studies of β-arrestin2 recruitment and biased signaling, aiming to provide new insights into the mechanisms and functions of endogenous opioid peptides, which are mediated through the OPRM1 7TM C-terminal splice variants.
Collapse
|
16
|
Murray K, Lin Y, Makary MM, Whang PG, Geha P. Brain Structure and Function of Chronic Low Back Pain Patients on Long-Term Opioid Analgesic Treatment: A Preliminary Study. Mol Pain 2021; 17:1744806921990938. [PMID: 33567986 PMCID: PMC7883154 DOI: 10.1177/1744806921990938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Chronic low back pain (CLBP) is often treated with opioid analgesics (OA), a class of medications associated with a significant risk of misuse. However, little is known about how treatment with OA affect the brain in chronic pain patients. Gaining this knowledge is a necessary first step towards understanding OA associated analgesia and elucidating long-term risk of OA misuse. Here we study CLBP patients chronically medicated with opioids without any evidence of misuse and compare them to CLBP patients not on opioids and to healthy controls using structural and functional brain imaging. CLBP patients medicated with OA showed loss of volume in the nucleus accumbens and thalamus, and an overall significant decrease in signal to noise ratio in their sub-cortical areas. Power spectral density analysis (PSD) of frequency content in the accumbens’ resting state activity revealed that both medicated and unmedicated patients showed loss of PSD within the slow-5 frequency band (0.01–0.027 Hz) while only CLBP patients on OA showed additional density loss within the slow-4 frequency band (0.027–0.073 Hz). We conclude that chronic treatment with OA is associated with altered brain structure and function within sensory limbic areas.
Collapse
Affiliation(s)
- Kyle Murray
- Department of Physics and Astronomy, University of Rochester, Rochester, NY, USA
| | - Yezhe Lin
- Department of Psychiatry, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Meena M Makary
- The John B. Pierce Laboratory, New Haven, CT, USA.,Department of Psychiatry, Yale School of Medicine, Yale University, New Haven, CT, USA.,Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Systems and Biomedical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt
| | - Peter G Whang
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, New Haven, CT, USA
| | - Paul Geha
- Department of Psychiatry, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.,The John B. Pierce Laboratory, New Haven, CT, USA.,Department of Psychiatry, Yale School of Medicine, Yale University, New Haven, CT, USA
| |
Collapse
|
17
|
Liao K, Niu F, Hu G, Yang L, Dallon B, Villarreal D, Buch S. Morphine-mediated release of miR-138 in astrocyte-derived extracellular vesicles promotes microglial activation. J Extracell Vesicles 2020; 10:e12027. [PMID: 33304479 PMCID: PMC7710131 DOI: 10.1002/jev2.12027] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/20/2020] [Accepted: 10/15/2020] [Indexed: 12/14/2022] Open
Abstract
Opioids, such as morphine, are the mainstay for the management of postsurgical pain. Over the last decade there has been a dramatic increase in deaths related to opioid overdose. While opioid abuse has been shown to result in increased neuroinflammation, mechanism(s) underlying this process, remain less understood. In recent years, microRNAs have emerged as key mediators of gene expression regulating both paracrine signaling and cellular crosstalk. MiRNAs constitute the extracellular vesicle (EV) cargo and can shuttle from the donor to the recipient cells. Exposure of human primary astrocytes to morphine resulted in induction and release of miR‐138 in the EVs isolated from conditioned media of cultured astrocytes. Released EVs were, in turn, taken up by the microglia, leading to activation of these latter cells. Interestingly, activation of microglia involved binding of the GUUGUGU motif of miR138 to the endosomal toll like receptor (TLR)7, leading, in turn, to cellular activation. These findings were further corroborated in vivo in wildtype mice wherein morphine administration resulted in increased microglial activation in the thalamus. In TLR7−/− mice on the other hand, morphine failed to induce microglial activation. These findings have ramifications for the development of EV‐loaded anti‐miRNAs as therapeutics for alleviating neuroinflammation in opioids abusers.
Collapse
Affiliation(s)
- Ke Liao
- Department of Pharmacology and Experimental Neuroscience University of Nebraska Medical Center Omaha Nebraska USA
| | - Fang Niu
- Department of Pharmacology and Experimental Neuroscience University of Nebraska Medical Center Omaha Nebraska USA
| | - Guoku Hu
- Department of Pharmacology and Experimental Neuroscience University of Nebraska Medical Center Omaha Nebraska USA
| | - Lu Yang
- Department of Pharmacology and Experimental Neuroscience University of Nebraska Medical Center Omaha Nebraska USA
| | - Blake Dallon
- Department of Pharmacology and Experimental Neuroscience University of Nebraska Medical Center Omaha Nebraska USA
| | - Delaney Villarreal
- Department of Pharmacology and Experimental Neuroscience University of Nebraska Medical Center Omaha Nebraska USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience University of Nebraska Medical Center Omaha Nebraska USA
| |
Collapse
|
18
|
Mizoguchi H, Fujii H. Exploring μ-Opioid Receptor Splice Variants as a Specific Molecular Target for New Analgesics. Curr Top Med Chem 2020; 20:2866-2877. [PMID: 32962616 DOI: 10.2174/1568026620666200922113430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/29/2020] [Accepted: 09/03/2020] [Indexed: 11/22/2022]
Abstract
Since a μ-opioid receptor gene containing multiple exons has been identified, the variety of splice variants for μ-opioid receptors have been reported in various species. Amidino-TAPA and IBNtxA have been discovered as new analgesics with different pharmacological profiles from morphine. These new analgesics show a very potent analgesic effect but do not have dependence liability. Interestingly, these analgesics show the selectivity to the morphine-insensitive μ-opioid receptor splice variants. The splice variants, sensitive to these new analgesics but insensitive to morphine, may be a better molecular target to develop the analgesics without side effects.
Collapse
Affiliation(s)
- Hirokazu Mizoguchi
- Department of Physiology and Anatomy, Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
| | - Hideaki Fujii
- Laboratory of Medicinal Chemistry and Medical Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| |
Collapse
|
19
|
Zhang XY, Dou YN, Yuan L, Li Q, Zhu YJ, Wang M, Sun YG. Different neuronal populations mediate inflammatory pain analgesia by exogenous and endogenous opioids. eLife 2020; 9:55289. [PMID: 32519950 PMCID: PMC7311172 DOI: 10.7554/elife.55289] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
Mu-opioid receptors (MORs) are crucial for analgesia by both exogenous and endogenous opioids. However, the distinct mechanisms underlying these two types of opioid analgesia remain largely unknown. Here, we demonstrate that analgesic effects of exogenous and endogenous opioids on inflammatory pain are mediated by MORs expressed in distinct subpopulations of neurons in mice. We found that the exogenous opioid-induced analgesia of inflammatory pain is mediated by MORs in Vglut2+ glutamatergic but not GABAergic neurons. In contrast, analgesia by endogenous opioids is mediated by MORs in GABAergic rather than Vglut2+ glutamatergic neurons. Furthermore, MORs expressed at the spinal level is mainly involved in the analgesic effect of morphine in acute pain, but not in endogenous opioid analgesia during chronic inflammatory pain. Thus, our study revealed distinct mechanisms underlying analgesia by exogenous and endogenous opioids, and laid the foundation for further dissecting the circuit mechanism underlying opioid analgesia.
Collapse
Affiliation(s)
- Xin-Yan Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Nong Dou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Lei Yuan
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Qing Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Jing Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Meng Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| |
Collapse
|
20
|
Zhang XY, Li Q, Dong Y, Yan W, Song K, Lin YQ, Sun YG. Mu-Opioid Receptors Expressed in Glutamatergic Neurons are Essential for Morphine Withdrawal. Neurosci Bull 2020; 36:1095-1106. [PMID: 32451910 DOI: 10.1007/s12264-020-00515-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/11/2020] [Indexed: 01/09/2023] Open
Abstract
Although opioids still remain the most powerful pain-killers, the chronic use of opioid analgesics is largely limited by their numerous side-effects, including opioid dependence. However, the mechanism underlying this dependence is largely unknown. In this study, we used the withdrawal symptoms precipitated by naloxone to characterize opioid dependence in mice. We determined the functional role of mu-opioid receptors (MORs) expressed in different subpopulations of neurons in the development of morphine withdrawal. We found that conditional deletion of MORs from glutamatergic neurons expressing vesicular glutamate transporter 2 (Vglut2+) largely eliminated the naloxone-precipitated withdrawal symptoms. In contrast, conditional deletion of MORs expressed in GABAergic neurons had a limited effect on morphine withdrawal. Consistently, mice with MORs deleted from Vglut2+ glutamatergic neurons also showed no morphine-induced locomotor hyperactivity. Furthermore, morphine withdrawal and morphine-induced hyperactivity were not significantly affected by conditional knockout of MORs from dorsal spinal neurons. Taken together, our data indicate that the development of morphine withdrawal is largely mediated by MORs expressed in Vglut2+ glutamatergic neurons.
Collapse
Affiliation(s)
- Xin-Yan Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Qing Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Ye Dong
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Wei Yan
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Kun Song
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yong-Qin Lin
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
| |
Collapse
|
21
|
Molecular Basis of Opioid Action: From Structures to New Leads. Biol Psychiatry 2020; 87:6-14. [PMID: 31653480 PMCID: PMC6898784 DOI: 10.1016/j.biopsych.2019.08.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/30/2019] [Accepted: 08/31/2019] [Indexed: 02/06/2023]
Abstract
Since the isolation of morphine from the opium poppy over 200 years ago, the molecular basis of opioid action has remained the subject of intense inquiry. The identification of specific receptors responsible for opioid function and the discovery of many chemically diverse molecules with unique opioid-like efficacies have provided glimpses into the molecular logic of opioid action. Recent revolutions in the structural biology of transmembrane proteins have, for the first time, yielded high-resolution views into the 3-dimensional shapes of all 4 opioid receptors. These studies have begun to decode the chemical logic that enables opioids to specifically bind and activate their receptor targets. A combination of spectroscopic experiments and computational simulations has provided a view into the molecular movements of the opioid receptors, which itself gives rise to the complex opioid pharmacology observed at the cellular and behavioral levels. Further diversity in opioid receptor structure is driven by both genetic variation and receptor oligomerization. These insights have enabled computational drug discovery efforts, with some evidence of success in the design of completely novel opioids with unique efficacies. The combined progress over the past few years provides hope for new, efficacious opioids devoid of the side effects that have made them the scourge of humanity for millennia.
Collapse
|
22
|
Le Rouzic V, Narayan A, Hunkle A, Marrone GF, Lu Z, Majumdar S, Xu J, Pan YX, Pasternak GW. Pharmacological Characterization of Levorphanol, a G-Protein Biased Opioid Analgesic. Anesth Analg 2019; 128:365-373. [PMID: 29649035 DOI: 10.1213/ane.0000000000003360] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Levorphanol is a potent analgesic that has been used for decades. Most commonly used for acute and cancer pain, it also is effective against neuropathic pain. The recent appreciation of the importance of functional bias and the uncovering of multiple µ opioid receptor splice variants may help explain the variability of patient responses to different opioid drugs. METHODS Here, we evaluate levorphanol in a variety of traditional in vitro receptor binding and functional assays. In vivo analgesia studies using the radiant heat tail flick assay explored the receptor selectivity of the responses through the use of knockout (KO) mice, selective antagonists, and viral rescue approaches. RESULTS Receptor binding studies revealed high levorphanol affinity for all the μ, δ, and κ opioid receptors. In S-GTPγS binding assays, it was a full agonist at most µ receptor subtypes, with the exception of MOR-1O, but displayed little activity in β-arrestin2 recruitment assays, indicating a preference for G-protein transduction mechanisms. A KO mouse and selective antagonists confirmed that levorphanol analgesia was mediated through classical µ receptors, but there was a contribution from 6 transmembrane targets, as illustrated by a lower response in an exon 11 KO mouse and its rescue with a virally transfected 6 transmembrane receptor splice variant. Compared to morphine, levorphanol had less respiratory depression at equianalgesic doses. CONCLUSIONS While levorphanol shares many of the same properties as the classic opioid morphine, it displays subtle differences that may prove helpful in its clinical use. Its G-protein signaling bias is consistent with its diminished respiratory depression, while its incomplete cross tolerance with morphine suggests it may prove valuable clinically with opioid rotation.
Collapse
Affiliation(s)
- Valerie Le Rouzic
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ankita Narayan
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Amanda Hunkle
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Gina F Marrone
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Zhigang Lu
- First Clinical Medical College, Nanjing University of Traditional Chinese Medicine, Nanjing, China
| | - Susruta Majumdar
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jin Xu
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ying-Xian Pan
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Gavril W Pasternak
- From the Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| |
Collapse
|
23
|
Chakrabarti S, Liu NJ, Gintzler AR. Phosphorylation of unique C-terminal sites of the mu-opioid receptor variants 1B2 and 1C1 influences their Gs association following chronic morphine. J Neurochem 2019; 152:449-467. [PMID: 31479519 DOI: 10.1111/jnc.14863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/14/2019] [Accepted: 08/11/2019] [Indexed: 11/27/2022]
Abstract
We recently demonstrated in rat spinal cord that a regimen of escalating doses of systemic morphine, analogous to regimens used clinically for chronic pain management, selectively up-regulates the mu-opioid receptor (MOR) splice variants MOR-1B2 and MOR-1C1 mRNA and functional protein. This study investigated the potential relevance of up-regulating MOR-1B2 and MOR-1C1 to the ability of chronic morphine to shift MOR signaling from predominantly Gi /Go inhibitory to Gs stimulatory. Specifically, we tested the hypotheses that chronic morphine induces phosphorylation of carboxyl terminal sites unique to MOR-1B2 and MOR-1C1, and that this phosphorylation is causally related to augmented association of these variants with Gs α. Hypotheses were validated by (i) abolition of the chronic morphine-induced increment in MOR-1C1 and MOR-1B2 association with Gs α by inhibitors of protein kinase A and Casein kinase 2, respectively; (ii) failure of chronic morphine to augment MOR variant Gs α interactions in Chinese hamster ovary cells transiently transfected with either rat MOR-1C1 or MOR-1B2 in which targeted protein kinase A and Casein kinase 2 serine phosphorylation sites, respectively, were mutated to alanine; (iii) abrogation of chronic morphine-induced augmented MOR Gs α association in spinal cord of male rats following intrathecal administration of dicer substrate small interfering RNAs targeting MOR-1B2/MOR-1C1 mRNA. The ability of chronic morphine to not only up-regulate-specific MOR variants but also their carboxyl terminal phosphorylation and consequent augmented association with Gs α may represent a novel component of opioid tolerance mechanisms, suggesting novel potential targets for tolerance abatement.
Collapse
Affiliation(s)
- Sumita Chakrabarti
- Department of Obstetrics and Gynecology, State University of New York, Downstate Medical Center, Brooklyn, New York, USA
| | - Nai-Jiang Liu
- Department of Obstetrics and Gynecology, State University of New York, Downstate Medical Center, Brooklyn, New York, USA
| | - Alan R Gintzler
- Department of Obstetrics and Gynecology, State University of New York, Downstate Medical Center, Brooklyn, New York, USA
| |
Collapse
|
24
|
Dynorphin/kappa-opioid receptor control of dopamine dynamics: Implications for negative affective states and psychiatric disorders. Brain Res 2019; 1713:91-101. [DOI: 10.1016/j.brainres.2018.09.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/12/2018] [Accepted: 09/19/2018] [Indexed: 02/06/2023]
|
25
|
Cunningham CW, Elballa WM, Vold SU. Bifunctional opioid receptor ligands as novel analgesics. Neuropharmacology 2019; 151:195-207. [PMID: 30858102 DOI: 10.1016/j.neuropharm.2019.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/30/2019] [Accepted: 03/02/2019] [Indexed: 12/12/2022]
Abstract
Prolonged treatment of chronic severe pain with opioid analgesics is frought with problematic adverse effects including tolerance, dependence, and life-threatening respiratory depression. Though these effects are mediated predominately through preferential activation of μ opioid peptide (μOP) receptors, there is an emerging appreciation that actions at κOP and δOP receptors contribute to the observed pharmacologic and behavioral profile of μOP receptor agonists and may be targeted simultaneously to afford improved analgesic effects. Recent developments have also identified the related nociceptin opioid peptide (NOP) receptor as a key modulator of the effects of μOP receptor signaling. We review here the available literature describing OP neurotransmitter systems and highlight recent drug and probe design strategies.
Collapse
Affiliation(s)
| | - Waleed M Elballa
- Department of Pharmaceutical Sciences, Concordia University Wisconsin, Mequon, WI, USA.
| | - Stephanie U Vold
- Department of Pharmaceutical Sciences, Concordia University Wisconsin, Mequon, WI, USA.
| |
Collapse
|
26
|
Dai Z, Chu H, Ma J, Yan Y, Zhang X, Liang Y. The Regulatory Mechanisms and Therapeutic Potential of MicroRNAs: From Chronic Pain to Morphine Tolerance. Front Mol Neurosci 2018; 11:80. [PMID: 29615865 PMCID: PMC5864932 DOI: 10.3389/fnmol.2018.00080] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/01/2018] [Indexed: 12/11/2022] Open
Abstract
Chronic pain, including cancer-related pain, is a pain condition often caused by inflammation or dysfunctional nerves. Chronic pain treatment poses a significant health care challenge, where opioids especially morphine are widely used and patients often develop tolerance over time with aggravated pain. microRNA (miRNA) is known to play important roles in regulating gene expressions in the nervous system to affect neuronal network plasticity related to algogenesis and the developing of morphine tolerance. In this article, we reviewed studies conducted in rodent animal models investigating the mechanisms of miRNAs regulation in chronic pain with different phenotypes and morphine tolerance. In addition, the potential of targeting miRNAs for chronic pain and morphine tolerance treatment is also reviewed. Finally, we point out the directions of the future research in chronic pain and morphine tolerance.
Collapse
Affiliation(s)
- Zhao Dai
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Haichen Chu
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jiahai Ma
- Department of Anesthesiology, The Affiliated Yantai Yuhuangding Hospital, Qingdao University, Qingdao, China
| | - Ying Yan
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xueying Zhang
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yongxin Liang
- Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| |
Collapse
|
27
|
Sader S, Anant K, Wu C. To probe interaction of morphine and IBNtxA with 7TM and 6TM variants of the human μ-opioid receptor using all-atom molecular dynamics simulations with an explicit membrane. Phys Chem Chem Phys 2018; 20:1724-1741. [PMID: 29265141 DOI: 10.1039/c7cp06745c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
IBNtxA, a morphine derivative, is 10-fold more potent and has a better safety profile than morphine. Animal studies indicate that the analgesic effect of IBNtxA appears to be mediated by the activation of truncated splice variants (6TM) of the Mu opioid receptor (MOR-1) where transmembrane helix 1 (TM1) is removed. Interestingly, morphine is unable to activate 6TM variants. To date, a high resolution structure of 6TM variants is missing, and the interaction of 6TM variants with IBNtxA and morphine remains elusive. In this study we used homology modeling, docking and molecular dynamics (MD) simulations to study a representative 6TM variant (G1) and a full-length 7TM variant of human MOR-1 in complex with IBNtxA and morphine respectively. The structural models of human G1 and 7TM were obtained by homology modeling using the X-ray solved crystal structure of the active mouse 7TM bound to an agonist BU72 (PDB id: ) as the template. Our 6000 ns MD data show that either TM1 truncation (i.e. from 7TM to 6TM) or ligand modification (i.e. from morphine to IBNtxA) alone causes the loss of key morphine-7TM interactions that are well-known to be required for MOR-1 activation. Receptor disruptions are mainly located at TMs 2, 3, 6 and 7 in comparison with the active crystal complex. However, when both perturbations occur in the 6TM-IBNtxA complex, the key ligand-receptor interactions and the receptor conformation are recovered to resemble those in the active 7TM-morphine complex. Our molecular switch analysis further explains well why morphine is not able to activate 6TM variants. The close resemblance between 6TM-IBTtxA and 7TM in complex with PZM21, a G-protein biased 7TM agonist, suggests the possible biased agonism of IBNtxA on G1, which is consistent with its reduced side effects.
Collapse
Affiliation(s)
- Safaa Sader
- College of Science and Mathematics, Rowan University, Glassboro, NJ 08028, USA.
| | | | | |
Collapse
|
28
|
Abstract
Nowadays, the delta opioid receptor (DOPr) represents a promising target for the treatment of chronic pain and emotional disorders. Despite the fact that they produce limited antinociceptive effects in healthy animals and in most acute pain models, DOPr agonists have shown efficacy in various chronic pain models. In this chapter, we review the progresses that have been made over the last decades in understanding the role played by DOPr in the control of pain. More specifically, the distribution of DOPr within the central nervous system and along pain pathways is presented. We also summarize the literature supporting a role for DOPr in acute, tonic, and chronic pain models, as well as the mechanisms regulating its activity under specific conditions. Finally, novel compounds that have make their way to clinical trials are discussed.
Collapse
Affiliation(s)
- Khaled Abdallah
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, QC, Canada
- Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
- Centre de recherche du CHUS, Sherbrooke, QC, Canada
| | - Louis Gendron
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Centre de recherche du CHUS, Sherbrooke, QC, Canada.
- Département d'anesthésiologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Quebec Pain Research Network, Sherbrooke, QC, Canada.
| |
Collapse
|
29
|
Dhar D, Poree LR, Yaksh TL. Evolution of the Spinal Delivery of Opiate Analgesics. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00065-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
30
|
Pasternak GW. Mu Opioid Pharmacology: 40 Years to the Promised Land. ADVANCES IN PHARMACOLOGY 2018; 82:261-291. [DOI: 10.1016/bs.apha.2017.09.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
31
|
Genetic dissociation of morphine analgesia from hyperalgesia in mice. Psychopharmacology (Berl) 2017; 234:1891-1900. [PMID: 28343361 PMCID: PMC5520541 DOI: 10.1007/s00213-017-4600-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/10/2017] [Indexed: 01/10/2023]
Abstract
RATIONALE Morphine is the prototypic mu opioid, producing its analgesic actions through traditional 7 transmembrane domain (7TM) G-protein-coupled receptors generated by the mu opioid receptor gene (Oprm1). However, the Oprm1 gene undergoes extensive alternative splicing to yield three structurally distinct sets of splice variants. In addition to the full-length 7TM receptors, it produces a set of truncated variants comprised of only 6 transmembrane domains (6TM). OBJECTIVES This study explored the relative contributions of 7TM and 6TM variants in a range of morphine actions. METHODS Groups of male and mixed-gender wild-type and exon 11 Oprm1 knockout mice were examined in a series of behavioral assays measuring analgesia, hyperalgesia, respiration, and reward in conditioned place preference assays. RESULTS Loss of the 6TM variants in an exon 11 knockout (E11 KO) mouse did not affect morphine analgesia, reward, or respiratory depression. However, E11 KO mice lacking 6TM variants failed to show morphine-induced hyperalgesia, developed tolerance more slowly than wild-type mice, and did not display hyperlocomotion. CONCLUSIONS Together, our findings confirm the established role of 7TM mu receptor variants in morphine analgesia, reward, and respiratory depression, but reveal an unexpected obligatory role for 6TM variants in morphine-induced hyperalgesia and a modulatory role in morphine tolerance and dependence.
Collapse
|
32
|
Chakrabarti S, Madia PA, Gintzler AR. Selective up-regulation of functional mu-opioid receptor splice variants by chronic opioids. J Neurochem 2016; 136:1119-1130. [PMID: 26718622 DOI: 10.1111/jnc.13519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 11/28/2022]
Abstract
We recently reported (Verzillo, et al. J. Neurochem: 130, 790-796, 2014) that chronic systemic morphine selectively up-regulates mRNA encoding two C-terminal μ-opioid receptor (MOR) splice variants, MOR-1C1 and MOR-1B2 (MOR-1B2/-1C1). Given the known disconnects between changes in levels of mRNA and corresponding protein, it is essential to directly demonstrate that chronic opioid treatment elevates functional MOR-1B2/-1C1 protein prior to inferring relevance of these MOR variants to spinal opioid tolerance mechanisms. Accordingly, we investigated the ability of chronic opioid exposure to up-regulate MOR protein in Chinese hamster ovary cells stably transfected with rat MOR variants MOR-1B2, MOR-1C1, or MOR-1 (considered to be the predominant MOR). Findings revealed that chronic treatment with the clinically relevant opioids morphine, oxycodone and hydrocodone substantially up-regulated membrane MOR-1B2/-1C1 protein. This up-regulation was abolished by the protein synthesis inhibitor cycloheximide, eliminating contributions from receptor redistribution. The increment in MOR-1B2/-1C1 protein was paralleled by a significant increment in opioid agonist-stimulated GTPγS-binding (reflective of increased aggregate MOR G protein coupling) indicating that up-regulated MOR-1B2/-1C1 represented functional receptors. Strikingly, these tolerance-associated adaptations of MOR-1B2/-1C1 differed considerably from those of MOR-1. Antithetical regulation of MOR-1B2/-1C1 and MOR-1 by chronic opioids has significant implications for the design of new therapeutic agents to counteract opioid analgesic tolerance and accompanying addiction. Since chronic opioids induce MOR-1B2/-1C1 up-regulation in spinal cord of males, but not females, elucidating cellular compartments and intracellular pathways mediating MOR-1B2/-1C1 up-regulation and defining their unique signaling attributes would enable a precision medicinal approach to pain management and addiction therapy. In the spinal cord of males, but not females, chronic morphine up-regulates mRNA encoding two mu-opioid receptor (MOR) variants, MOR-1B2 and MOR-1C1 (MOR-1B2/-1C1). We now demonstrate that chronic treatment with the clinically relevant opioids morphine, hydrocodone or oxycodone up-regulates MOR-1B2/-1C1 functional protein, which is dependent on de novo protein synthesis. Findings underscore the importance of unique signaling attributes of MOR variants to sexually dimorphic tolerance mechanisms.
Collapse
Affiliation(s)
- Sumita Chakrabarti
- Department of Obstetrics and Gynecology, State University of New York, Brooklyn, New York, USA
| | - Priyanka A Madia
- Department of Obstetrics and Gynecology, State University of New York, Brooklyn, New York, USA
| | - Alan R Gintzler
- Department of Obstetrics and Gynecology, State University of New York, Brooklyn, New York, USA
| |
Collapse
|
33
|
Involvement of opioid signaling in food preference and motivation. PROGRESS IN BRAIN RESEARCH 2016; 229:159-187. [DOI: 10.1016/bs.pbr.2016.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
34
|
Abstract
• Individual variability in pain perception and differences in the efficacy of analgesic drugs are complex phenomena and are partly genetically predetermined. • Analgesics act in various ways on the peripheral and central pain pathways and are regarded as one of the most valuable but equally dangerous groups of medications. • While pharmacokinetic properties of drugs, metabolism in particular, have been scrutinised by genotype–phenotype correlation studies, the clinical significance of inherited variants in genes governing pharmacodynamics of analgesics remains largely unexplored (apart from the µ-opioid receptor). • Lack of replication of the findings from one study to another makes meaningful personalised analgesic regime still a distant future. • This narrative review will focus on findings related to pharmacogenetics of commonly used analgesic medications and highlight authors’ views on future clinical implications of pharmacogenetics in the context of pharmacological treatment of chronic pain.
Collapse
Affiliation(s)
- Roman Cregg
- UCL Centre for Anaesthesia, Critical Care & Pain Medicine, London, UK ; Royal Marsden NHS Foundation Trust, London, UK
| | | | | | | | | |
Collapse
|
35
|
Gretton SK, Droney J. Splice variation of the mu-opioid receptor and its effect on the action of opioids. Br J Pain 2015; 8:133-8. [PMID: 26516547 DOI: 10.1177/2049463714547115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
An individual's response to opioids is influenced by a complex combination of genetic, molecular and phenotypic factors.Intra- and inter-individual variations in response to mu opioids have led to the suggestion that mu-opioid receptor subtypes exist.Scientists have now proven that mu-opioid receptor subtypes exist and that they occur through a mechanism promoting protein diversity, called alternative splicing.The ability of mu opioids to differentially activate splice variants may explain some of the clinical differences observed between mu opioids.This article examines how differential activation of splice variants by mu opioids occurs through alternative mu-opioid receptor binding, through differential receptor activation, and as a result of the distinct distribution of variants located regionally and at the cellular level.
Collapse
|
36
|
Ickert I, Herten M, Vogl M, Ziskoven C, Zilkens C, Krauspe R, Kircher J. Opioids as an alternative to amide-type local anaesthetics for intra-articular application. Knee Surg Sports Traumatol Arthrosc 2015; 23:2674-81. [PMID: 24792069 DOI: 10.1007/s00167-014-2989-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 04/03/2014] [Indexed: 01/09/2023]
Abstract
PURPOSE Recently, the safety profile of local anaesthetics in intra-articular use became into focus of investigation. Opioid drugs have a different mode of action and may be a safe and potent alternative for intra-articular application. The purpose of this in vitro study is to provide evidence for significant chondrotoxicity of amide-type local anaesthetics even after short-term application on human chondrocytes and to demonstrate the absence of such negative effects for opioids [morphine, morphine-6-glucuronide (M6G)]. METHOD Visually intact cartilage explants of human, mainly osteoarthritic joints (n = 9), were harvested and cultivated in monolayer for expansion and transferred into alginate bead. The beads were incubated for increasing incubation times (15 min, 1 and 4 h) in decreasing concentrations (full, ½, ¼ for 15 min) of bupivacaine, ropivacaine, morphine, M6G or saline control. Adenosine triphosphate content of 798 beads was measured 3 days post-incubation to assess cell viability. RESULTS A clear ranking of cytotoxic potency: bupivacaine > ropivacaine > morphine = M6G = saline was observed. Results reveal a dose- and time-dependent manner of cytotoxic effects on human chondrocytes for bupivacaine and ropivacaine but not for opioids. Cell viability after exposure to morphine and M6G was comparable to exposure to saline. CONCLUSION The results confirm dose- and time-dependent cytotoxic effects on human chondrocytes for amide-type local anaesthetics. This study confirms the safety of morphine and M6G in terms of an absence of cytotoxic effects after intra-articular application, making them safe potential alternatives in clinical practice.
Collapse
Affiliation(s)
- Irina Ickert
- Department of Orthopedics, University Hospital, Heinrich-Heine-University, Duesseldorf, Germany
| | | | | | | | | | | | | |
Collapse
|
37
|
Mann M, Chhun S, Pons G. Farmacogenetica dei farmaci antiepilettici. Neurologia 2014. [DOI: 10.1016/s1634-7072(14)68868-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
|
38
|
Xu J, Lu Z, Xu M, Rossi GC, Kest B, Waxman AR, Pasternak GW, Pan YX. Differential expressions of the alternatively spliced variant mRNAs of the µ opioid receptor gene, OPRM1, in brain regions of four inbred mouse strains. PLoS One 2014; 9:e111267. [PMID: 25343478 PMCID: PMC4208855 DOI: 10.1371/journal.pone.0111267] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 09/19/2014] [Indexed: 01/20/2023] Open
Abstract
The µ opioid receptor gene, OPRM1, undergoes extensive alternative pre-mRNA splicing in rodents and humans, with dozens of alternatively spliced variants of the OPRM1 gene. The present studies establish a SYBR green quantitative PCR (qPCR) assay to more accurately quantify mouse OPRM1 splice variant mRNAs. Using these qPCR assays, we examined the expression of OPRM1 splice variant mRNAs in selected brain regions of four inbred mouse strains displaying differences in µ opioid-induced tolerance and physical dependence: C56BL/6J, 129P3/J, SJL/J and SWR/J. The complete mRNA expression profiles of the OPRM1 splice variants reveal marked differences of the variant mRNA expression among the brain regions in each mouse strain, suggesting region-specific alternative splicing of the OPRM1 gene. The expression of many variants was also strain-specific, implying a genetic influence on OPRM1 alternative splicing. The expression levels of a number of the variant mRNAs in certain brain regions appear to correlate with strain sensitivities to morphine analgesia, tolerance and physical dependence in four mouse strains.
Collapse
Affiliation(s)
- Jin Xu
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Zhigang Lu
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Mingming Xu
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Grace C. Rossi
- Department of Psychology, Long Island University, Post Campus, Brookville, New York, United States of America
| | - Benjamin Kest
- Department of Psychology and Center for Developmental Neuroscience, City University of New York, Staten Island, New York, United States of America
| | - Amanda R. Waxman
- Department of Psychology and Center for Developmental Neuroscience, City University of New York, Staten Island, New York, United States of America
| | - Gavril W. Pasternak
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Ying-Xian Pan
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| |
Collapse
|
39
|
NABIPOUR S, AYU SAID M, HUSSAIN HABIL M. Burden and nutritional deficiencies in opiate addiction- systematic review article. IRANIAN JOURNAL OF PUBLIC HEALTH 2014; 43:1022-32. [PMID: 25927032 PMCID: PMC4411899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 07/27/2014] [Indexed: 10/24/2022]
Abstract
Addiction to the illicit and prescribed use of opiate is an alarming public health issue. Studies on addictive disorders have demonstrated severe nutritional deficiencies in opiate abusers with behavioral, physiological and cognitive symptoms. Opiate addiction is also link with a significant number of diseases including Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV) and other blood borne diseases generally stem from the use of needles to inject heroin. The use of medication assisted treatment for opioid addicts in combination with behavioural therapies has been considered as a highly effective treatment. Methadone is a long-lasting μ-opioid agonist and a pharmacological tool which attenuates withdrawal symptoms effectively replacement therapies. This review article aims to explain opiate addiction mechanisms, epidemiology and disease burden with emphasis on dietary and nutritional status of opiate dependent patients in methadone maintenance therapy.
Collapse
Affiliation(s)
- Sepideh NABIPOUR
- 1. Dept. of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mas AYU SAID
- 1. Dept. of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia,* Corresponding Author:
| | - Mohd HUSSAIN HABIL
- 2. Dept. of Psychological Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| |
Collapse
|
40
|
Kawabe T, Ueyama T, Hano T, Sapru HN. Cardiovascular responses to microinjections of endomorphin-2 into the nucleus of the solitary tract are attenuated in the spontaneously hypertensive rat. Clin Exp Hypertens 2014; 37:197-206. [DOI: 10.3109/10641963.2014.933969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Tetsuya Kawabe
- Center for Educational Research and Development, Wakayama Medical University, Wakayama, Japan,
| | - Takashi Ueyama
- Department of Anatomy and Cell Biology, Wakayama Medical University, Wakayama, Japan, and
| | - Takuzo Hano
- Center for Educational Research and Development, Wakayama Medical University, Wakayama, Japan,
| | - Hreday N. Sapru
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, NJ, USA
| |
Collapse
|
41
|
Abstract
Opioids remain the mainstay of severe pain management in patients with cancer. The hallmark of pain management is individualization of therapy. Although almost all clinically used drugs act through mu opioid receptors, they display subtle but important differences pharmacologically. Furthermore, not all patients respond equally well to all drugs. Evidence suggests that these variable responses among patients have a biologic basis and are likely to involve both biased agonism and the many mu opioid receptor subtypes that have been cloned.
Collapse
Affiliation(s)
- Gavril W Pasternak
- From Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY.
| |
Collapse
|
42
|
Xu J, Xu M, Bolan E, Gilbert AK, Pasternak GW, Pan YX. Isolating and characterizing three alternatively spliced mu opioid receptor variants: mMOR-1A, mMOR-1O, and mMOR-1P. Synapse 2014; 68:144-52. [PMID: 24375714 DOI: 10.1002/syn.21727] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 11/27/2013] [Accepted: 12/16/2013] [Indexed: 12/21/2022]
Abstract
Extensive alternative pre-mRNA splicing of the mu opioid receptor gene, OPRM1, has demonstrated an array of splice variants in mice, rats and humans. Three classes of splice variants have been identified: full-length seven transmembrane (TM) domain variants with C-terminal splicing, truncated 6TM variants and single TM variants. The current studies isolates and characterizes an additional three full-length C-terminal splice variants generated from the mouse OPRM1 gene: mMOR-1A, mMOR-1O, and mMOR-1P. Using RT-qPCR, we demonstrated differential expression of these variants' mRNAs among selected brain regions, supporting region-specific alternative splicing. When expressed in Chinese Hamster Ovary cells, all the variants displayed high mu binding affinity and selectivity with subtle differences in the affinities toward some agonists. [³⁵S]γGTP binding assays revealed marked differences in agonist-induced G protein activation in both potency and efficacy among the variants. Together with the previous studies of mu agonist-induced phosphorylation and internalization in several carboxyl terminal splice variants, the current studies further suggest the existence of biased signaling of various agonists within each individual variant and/or among different variants.
Collapse
Affiliation(s)
- Jin Xu
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York, 10065
| | | | | | | | | | | |
Collapse
|
43
|
Mizoguchi H, Takagi H, Watanabe C, Yonezawa A, Sato T, Sakurada T, Sakurada S. Involvement of multiple µ-opioid receptor subtypes on the presynaptic or postsynaptic inhibition of spinal pain transmission. Peptides 2014; 51:15-25. [PMID: 24512946 DOI: 10.1016/j.peptides.2013.10.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 10/16/2013] [Accepted: 10/16/2013] [Indexed: 11/17/2022]
Abstract
The involvement of the μ-opioid receptor subtypes on the presynaptic or postsynaptic inhibition of spinal pain transmission was characterized in ddY mice using endomorphins. Intrathecal treatment with capsaicin, N-methyl-d-aspartate (NMDA) or substance P elicited characteristic nociceptive behaviors that consisted primarily of vigorous biting and/or licking with some scratching. Intrathecal co-administration of endogenous μ-opioid peptide endomorphin-1 or endomorphin-2 resulted in a potent antinociceptive effect against the nociceptive behaviors induced by capsaicin, NMDA or substance P, which was eliminated by i.t. co-administration of the μ-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP). The antinociceptive effect of endomorphin-1 was significantly suppressed by i.t.-co-administration of the μ2-opioid receptor antagonist Tyr-D-Pro-Trp-Phe-NH2 (D-Pro2-endomorphin-1) but not the μ1-opioid receptor antagonist Tyr-D-Pro-Phe-Phe-NH2 (D-Pro2-endomorphin-2) on capsaicin- or NMDA-elicited nociceptive behaviors. In contrast, the antinociceptive effect of endomorphin-2 was significantly suppressed by i.t.-co-administration of D-Pro2-endomorphin-2 but not D-Pro2-endomorphin-1 on capsaicin-, NMDA- or substance P-elicited nociceptive behaviors. Interestingly, regarding substance P-elicited nociceptive behaviors, the antinociceptive effect of endomorphin-1 was significantly suppressed by i.t.-co-administration of another μ2-opioid receptor antagonist, Tyr-D-Pro-Trp-Gly-NH2 (D-Pro2-Tyr-W-MIF-1), but not D-Pro2-endomorphin-1 or D-Pro2-endomorphin-2. The present results suggest that the multiple μ-opioid receptor subtypes are involved in the presynaptic or postsynaptic inhibition of spinal pain transmission.
Collapse
|
44
|
Pasternak GW. Opioids and their receptors: Are we there yet? Neuropharmacology 2014; 76 Pt B:198-203. [PMID: 23624289 PMCID: PMC4216569 DOI: 10.1016/j.neuropharm.2013.03.039] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/02/2013] [Accepted: 03/26/2013] [Indexed: 01/06/2023]
Abstract
Opioids have an important place in pharmacology. While their clinical use as analgesics is fundamental in medicine, their use is constrained by their side-effects and abuse potential. Pharmacologists have sought analgesics lacking side-effects and the abuse liability of the current agents. The identification of the opioid receptors in 1973 marked the beginning of our understanding of the molecular mechanisms of these agents. The isolation of the opioid peptides quickly followed, along with the classification of three families of opioid receptors. Clinicians have long been aware of subtle differences among the mu opioids that were not easily reconciled with a single receptor and selective antagonists implied two subdivisions of mu receptors. However, the cloning of the mu opioid receptor MOR-1 has led to the realization of the extensive complexity of the mu opioid receptor gene and its vast array of splice variants. Many of these splice variants are truncated and do not conform to the structure of traditional G-protein coupled receptors. Yet, evidence now shows that they are quite important and may prove valuable targets in the development of potent analgesics lacking the undesirable properties of current opioids. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
Collapse
Affiliation(s)
- Gavril W Pasternak
- Molecular Pharmacology and Chemistry Program, Department of Neurology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065, USA.
| |
Collapse
|
45
|
Abstract
Opiates are among the oldest medications available to manage a number of medical problems. Although pain is the current focus, early use initially focused upon the treatment of dysentery. Opium contains high concentrations of both morphine and codeine, along with thebaine, which is used in the synthesis of a number of semisynthetic opioid analgesics. Thus, it is not surprising that new agents were initially based upon the morphine scaffold. The concept of multiple opioid receptors was first suggested almost 50 years ago (Martin, 1967), opening the possibility of new classes of drugs, but the morphine-like agents have remained the mainstay in the medical management of pain. Termed mu, our understanding of these morphine-like agents and their receptors has undergone an evolution in thinking over the past 35 years. Early pharmacological studies identified three major classes of receptors, helped by the discovery of endogenous opioid peptides and receptor subtypes-primarily through the synthesis of novel agents. These chemical biologic approaches were then eclipsed by the molecular biology revolution, which now reveals a complexity of the morphine-like agents and their receptors that had not been previously appreciated.
Collapse
Affiliation(s)
- Gavril W Pasternak
- Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065.
| | | |
Collapse
|
46
|
Inhibition of Gβγ-subunit signaling potentiates morphine-induced antinociception but not respiratory depression, constipation, locomotion, and reward. Behav Pharmacol 2013; 24:144-52. [PMID: 23412114 DOI: 10.1097/fbp.0b013e32835f3d2f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Inhibition of Gβγ-subunit signaling to phospholipase C β3 has been shown to potentiate morphine-mediated antinociception while attenuating the development of tolerance and dependence in mice. The objective of this study was to determine the effect of Gβγ-subunit inhibition on antinociception and other pharmacological effects, such as respiratory depression, constipation, and hyperlocomotion, mediated by the μ-opioid receptor. The Gβγ-subunit inhibitor, gallein, was administered to C57BL/6J mice by intraperitoneal injection before morphine, and data were compared with mice treated with vehicle, morphine, or gallein alone. Morphine-induced antinociception was measured using the 55°C warm-water tail-withdrawal test. Pretreatment with gallein produced a dose-dependent potentiation of morphine-mediated antinociception, producing up to a 10-fold leftward shift in the morphine dose-response curve and extending the duration of antinociception induced by a single dose of morphine. Gallein pretreatment also prevented acute antinociceptive tolerance induced by morphine. In contrast, the dose-dependent respiratory depression and hyperlocomotion induced by morphine were not potentiated by gallein pretreatment. Similarly, gallein pretreatment did not potentiate morphine-conditioned place preference responses or morphine-induced constipation, as measured as a reduction in excreta. These results suggest that selectively inhibiting Gβγ-mediated signaling may selectively increase μ-opioid receptor-mediated antinociception without matching increases in adverse physiological effects.
Collapse
|
47
|
Pharmacological traits of delta opioid receptors: pitfalls or opportunities? Psychopharmacology (Berl) 2013; 228:1-18. [PMID: 23649885 PMCID: PMC3679311 DOI: 10.1007/s00213-013-3129-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/15/2013] [Indexed: 12/11/2022]
Abstract
RATIONALE Delta opioid receptors (DORs) have been considered as a potential target to relieve pain as well as treat depression and anxiety disorders and are known to modulate other physiological responses, including ethanol and food consumption. A small number of DOR-selective drugs are in clinical trials, but no DOR-selective drugs have been approved by the Federal Drug Administration and some candidates have failed in phase II clinical trials, highlighting current difficulties producing effective delta opioid-based therapies. Recent studies have provided new insights into the pharmacology of the DOR, which is often complex and at times paradoxical. OBJECTIVE This review will discuss the existing literature focusing on four aspects: (1) Two DOR subtypes have been postulated based on differences in pharmacological effects of existing DOR-selective ligands. (2) DORs are expressed ubiquitously throughout the body and central nervous system and are, thus, positioned to play a role in a multitude of diseases. (3) DOR expression is often dynamic, with many reports of increased expression during exposure to chronic stimuli, such as stress, inflammation, neuropathy, morphine, or changes in endogenous opioid tone. (4) A large structural variety in DOR ligands implies potential different mechanisms of activating the receptor. CONCLUSION The reviewed features of DOR pharmacology illustrate the potential benefit of designing tailored or biased DOR ligands.
Collapse
|
48
|
Mizoguchi H, Watanabe C, Higashiya T, Takeda S, Moriyama K, Aoki Y, Kon-no T, Takagi H, Yonezawa A, Sato T, Sakurada T, Sakurada S. Distinct physiological role of amidino-TAPA-sensitive and DAMGO-insensitive μ-opioid receptor splice variants in the mouse spinal cord. Eur J Pharmacol 2013; 711:80-6. [DOI: 10.1016/j.ejphar.2013.04.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 03/28/2013] [Accepted: 04/03/2013] [Indexed: 10/26/2022]
|
49
|
Xu J, Xu M, Brown T, Rossi GC, Hurd YL, Inturrisi CE, Pasternak GW, Pan YX. Stabilization of the μ-opioid receptor by truncated single transmembrane splice variants through a chaperone-like action. J Biol Chem 2013; 288:21211-21227. [PMID: 23760268 DOI: 10.1074/jbc.m113.458687] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The μ-opioid receptor gene, OPRM1, undergoes extensive alternative pre-mRNA splicing, as illustrated by the identification of an array of splice variants generated by both 5' and 3' alternative splicing. The current study reports the identification of another set of splice variants conserved across species that are generated through exon skipping or insertion that encodes proteins containing only a single transmembrane (TM) domain. Using a Tet-Off system, we demonstrated that the truncated single TM variants can dimerize with the full-length 7-TM μ-opioid receptor (MOR-1) in the endoplasmic reticulum, leading to increased expression of MOR-1 at the protein level by a chaperone-like function that minimizes endoplasmic reticulum-associated degradation. In vivo antisense studies suggested that the single TM variants play an important role in morphine analgesia, presumably through modulation of receptor expression levels. Our studies suggest the functional roles of truncated receptors in other G protein-coupled receptor families.
Collapse
Affiliation(s)
- Jin Xu
- From the Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Ming Xu
- From the Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Taylor Brown
- From the Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Grace C Rossi
- the Department of Psychology, CW Post College, Long Island University, Brookville, New York 11568
| | - Yasmin L Hurd
- the Department of Psychiatry and Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York 10029, and
| | - Charles E Inturrisi
- the Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065
| | - Gavril W Pasternak
- From the Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065,; the Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065.
| | - Ying-Xian Pan
- From the Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065,.
| |
Collapse
|
50
|
Yekkirala AS. Two to tango: GPCR oligomers and GPCR-TRP channel interactions in nociception. Life Sci 2013; 92:438-45. [DOI: 10.1016/j.lfs.2012.06.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/15/2012] [Accepted: 06/22/2012] [Indexed: 11/16/2022]
|