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Cheng L, Miao Z, Liu S, Li Z, Fu H, Xu C, Hu S, Zhao C, Liu Y, Zhao T, Liu W, Wang H, Liu R, Yan W, Tang X, Liu J, Shao Z, Ke B. Cryo-EM structure of small-molecule agonist bound delta opioid receptor-G i complex enables discovery of biased compound. Nat Commun 2024; 15:8284. [PMID: 39333070 DOI: 10.1038/s41467-024-52601-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 09/12/2024] [Indexed: 09/29/2024] Open
Abstract
Delta opioid receptor (δOR) plays a pivotal role in modulating human sensation and emotion. It is an attractive target for drug discovery since, unlike Mu opioid receptor, it is associated with low risk of drug dependence. Despite its potential applications, the pharmacological properties of δOR, including the mechanisms of activation by small-molecule agonists and the complex signaling pathways it engages, as well as their relation to the potential side effects, remain poorly understood. In this study, we use cryo-electron microscopy (cryo-EM) to determine the structure of the δOR-Gi complex when bound to a small-molecule agonist (ADL5859). Moreover, we design a series of probes to examine the key receptor-ligand interaction site and identify a region involved in signaling bias. Using ADL06 as a chemical tool, we elucidate the relationship between the β-arrestin pathway of the δOR and its biological functions, such as analgesic tolerance and convulsion activities. Notably, we discover that the β-arrestin recruitment of δOR might be linked to reduced gastrointestinal motility. These insights enhance our understanding of δOR's structure, signaling pathways, and biological functions, paving the way for the structure-based drug discovery.
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Affiliation(s)
- Lin Cheng
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Zhuang Miao
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Sicen Liu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Frontiers Medical Center, Tianfu Jincheng Laboratory, Chengdu, China
| | - Zhe Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Hong Fu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Chanjuan Xu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shilong Hu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Chang Zhao
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yuxuan Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Tiantian Zhao
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Wencheng Liu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Heli Wang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Runduo Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, P. R. China
| | - Wei Yan
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xiangdong Tang
- Sleep Medicine Center, Mental Health Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, and College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China.
| | - Zhenhua Shao
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
- Frontiers Medical Center, Tianfu Jincheng Laboratory, Chengdu, China.
| | - Bowen Ke
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
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Sperry MM, Charrez B, Fotowat H, Gardner E, Pilobello K, Izadifar Z, Lin T, Kuelker A, Kaki S, Lewandowski M, Lightbown S, Martinez R, Marquez S, Moore J, Plaza-Oliver M, Sesay AM, Shcherbina K, Sheehan K, Takeda T, Del Campo D, Andrijauskaite K, Cisneros E, Lopez R, Cano I, Maxwell Z, Jessop I, Veraza R, Bunegin L, Percival TJ, Yracheta J, Pena JJ, Wood DM, Homas ZT, Hinshaw CJ, Cox-Hinshaw J, Parry OG, Sleeter JJ, Weitzel EK, Levin M, Super M, Novak R, Ingber DE. Identification of pharmacological inducers of a reversible hypometabolic state for whole organ preservation. eLife 2024; 13:RP93796. [PMID: 39316042 PMCID: PMC11421850 DOI: 10.7554/elife.93796] [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: 09/25/2024] Open
Abstract
Drugs that induce reversible slowing of metabolic and physiological processes would have great value for organ preservation, especially for organs with high susceptibility to hypoxia-reperfusion injury, such as the heart. Using whole-organism screening of metabolism, mobility, and development in Xenopus, we identified an existing drug, SNC80, that rapidly and reversibly slows biochemical and metabolic activities while preserving cell and tissue viability. Although SNC80 was developed as a delta opioid receptor activator, we discovered that its ability to slow metabolism is independent of its opioid modulating activity as a novel SNC80 analog (WB3) with almost 1000 times less delta opioid receptor binding activity is equally active. Metabolic suppression was also achieved using SNC80 in microfluidic human organs-on-chips, as well as in explanted whole porcine hearts and limbs, demonstrating the cross-species relevance of this approach and potential clinical relevance for surgical transplantation. Pharmacological induction of physiological slowing in combination with organ perfusion transport systems may offer a new therapeutic approach for tissue and organ preservation for transplantation, trauma management, and enhancing patient survival in remote and low-resource locations.
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Affiliation(s)
- Megan M Sperry
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
- Department of Biology, Tufts UniversityMedfordUnited States
| | - Berenice Charrez
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Haleh Fotowat
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Erica Gardner
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Kanoelani Pilobello
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Zohreh Izadifar
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Tiffany Lin
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Abigail Kuelker
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Sahith Kaki
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Michael Lewandowski
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Shanda Lightbown
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Ramses Martinez
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Susan Marquez
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Joel Moore
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Maria Plaza-Oliver
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
- DEVANA group, Faculty of Pharmacy, University of Castilla-La ManchaCiudad RealSpain
| | - Adama M Sesay
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Kostyantyn Shcherbina
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Katherine Sheehan
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Takako Takeda
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Daniela Del Campo
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | | | - Exal Cisneros
- Vascular Perfusion Solutions IncSan AntonioUnited States
| | - Riley Lopez
- Vascular Perfusion Solutions IncSan AntonioUnited States
| | - Isabella Cano
- Vascular Perfusion Solutions IncSan AntonioUnited States
| | | | - Israel Jessop
- Vascular Perfusion Solutions IncSan AntonioUnited States
| | - Rafa Veraza
- Vascular Perfusion Solutions IncSan AntonioUnited States
| | - Leon Bunegin
- Vascular Perfusion Solutions IncSan AntonioUnited States
| | - Thomas J Percival
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Jaclyn Yracheta
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Jorge J Pena
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Diandra M Wood
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Zachary T Homas
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Cody J Hinshaw
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | | | - Olivia G Parry
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Justin J Sleeter
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Erik K Weitzel
- RESTOR, 59th Medical Wing, JBSA, Lackland AFBSan AntonioUnited States
| | - Michael Levin
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
- Department of Biology, Tufts UniversityMedfordUnited States
- Allen Center, Tufts UniversityMedfordUnited States
| | - Michael Super
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Richard Novak
- Wyss Institute for Biologically Inspired Engineering at Harvard UniversityBostonUnited States
| | - Donald E Ingber
- Vascular Biology Program & Department of Surgery, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
- Harvard John A. Paulson School of Engineering and Applied SciencesBostonUnited States
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3
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Hwang JY, Sohn HM, Kim JH, Park S, Park JW, Lim MS, Han SH. Reproducible Motor Deficit Following Aortic Occlusion in a Rat Model Of Spinal Cord Ischemia. J Vis Exp 2017. [PMID: 28784973 DOI: 10.3791/55814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Spinal cord ischemia is a fatal complication following thoracoabdominal aortic aneurysm surgery. Researchers can investigate the strategies for preventing and treating this complication using experimental models of spinal cord ischemia. The model described here demonstrates varying degrees of paraplegia that relate to the length of occlusion following thoracic aortic occlusion in a rat spinal cord ischemia model. A 2-Fr. balloon-tipped catheter was advanced through the femoral artery into the descending thoracic aorta until the catheter tip was placed at the left subclavian artery in anesthetized male Sprague-Dawley rats. Spinal cord ischemia was induced by inflating the catheter balloon. After a set period of occlusion (9, 10, or 11 min), the balloon was deflated. Neurologic assessment was performed using the motor deficit index at 24 h after surgery, and the spinal cord was harvested for histopathological examination. Rats that underwent 9 min of aortic occlusion showed mild and reversible motor impairment in the hind limb. Rats subjected to 10 min of aortic occlusion presented with moderate but reversible motor impairment. Rats subjected to 11 min of aortic occlusion displayed complete and persistent paralysis. The motor neurons in the spinal cord sections were more preserved in rats subjected to shorter duration of aortic occlusion. Researchers can achieve a reproducible hind limb motor deficit following thoracic aortic occlusion using this spinal cord ischemia model.
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Affiliation(s)
- Jin-Young Hwang
- Department of Anesthesiology and Pain Medicine, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul
| | - Hye-Min Sohn
- Department of Anesthesiology and Pain Medicine, SNU Bundang Hospital, Seongnamsi, Gyeonggido, Republic of Korea
| | - Jin-Hee Kim
- Department of Anesthesiology and Pain Medicine, SNU Bundang Hospital, Seongnamsi, Gyeonggido, Republic of Korea
| | - Seongjoo Park
- Department of Anesthesiology and Pain Medicine, SNU Bundang Hospital, Seongnamsi, Gyeonggido, Republic of Korea
| | - Jin-Woo Park
- Department of Anesthesiology and Pain Medicine, SNU Bundang Hospital, Seongnamsi, Gyeonggido, Republic of Korea
| | - Mi-Sun Lim
- Department of Anesthesiology and Pain Medicine, SNU Bundang Hospital, Seongnamsi, Gyeonggido, Republic of Korea
| | - Sung-Hee Han
- Department of Anesthesiology and Pain Medicine, SNU Bundang Hospital, Seongnamsi, Gyeonggido, Republic of Korea;
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4
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Grant Liska M, Crowley MG, Lippert T, Corey S, Borlongan CV. Delta Opioid Receptor and Peptide: A Dynamic Therapy for Stroke and Other Neurological Disorders. Handb Exp Pharmacol 2017; 247:277-299. [PMID: 28315071 DOI: 10.1007/164_2017_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Research of the opioid system and its composite receptors and ligands has revealed its promise as a potential therapy for neurodegenerative diseases such as stroke and Parkinson's Disease. In particular, delta opioid receptors (DORs) have been elucidated as a therapeutically distinguished subset of opioid receptors and a compelling target for novel intervention techniques. Research is progressively shedding light on the underlying mechanism of DORs and has revealed two mechanisms of DOR neuroprotection; DORs function to maintain ionic homeostasis and also to trigger endogenous neuroprotective pathways. Delta opioid agonists such as (D-Ala2, D-Leu5) enkephalin (DADLE) have been shown to promote neuronal survival and decrease apoptosis, resulting in a substantial amount of research for its application as a neurological therapeutic. Most notably, DADLE has demonstrated significant potential to reduce cell death following ischemic events. Current research is working to reveal the complex mechanisms of DADLE's neuroprotective properties. Ultimately, our knowledge of the DOR receptors and agonists has made the opioid system a promising target for therapeutic intervention in many neurological disorders.
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Affiliation(s)
- M Grant Liska
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Marci G Crowley
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Trenton Lippert
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Sydney Corey
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA
| | - Cesar V Borlongan
- Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, Tampa, FL, 33612, USA.
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5
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Liu H, Chen B, Li S, Yao J. Dose-dependent neuroprotection of delta-opioid peptide [D-Ala 2 , D-Leu 5 ] enkephalin on spinal cord ischemia-reperfusion injury by regional perfusion into the abdominal aorta in rabbits. J Vasc Surg 2016; 63:1074-81. [DOI: 10.1016/j.jvs.2014.11.074] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/15/2014] [Indexed: 11/15/2022]
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6
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Protective effect of delta opioid agonist [d-Ala2, d-Leu5] enkephalin on spinal cord ischemia reperfusion injury by regional perfusion into abdominal aorta in rabbits. Neurosci Lett 2015; 584:1-6. [DOI: 10.1016/j.neulet.2014.09.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 12/11/2022]
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Loriga G, Lazzari P, Ruiu S, Marchese G, Manca I, Casu GL, Dessì C, Pinna GA, Asproni B, Murineddu G. Synthesis and biological evaluation of novel delta (δ) opioid receptor ligands with diazatricyclodecane skeletons. Eur J Med Chem 2013; 69:413-26. [PMID: 24090913 DOI: 10.1016/j.ejmech.2013.09.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 09/03/2013] [Accepted: 09/05/2013] [Indexed: 12/01/2022]
Abstract
Considering the interesting pharmacological profile of the delta (δ) selective opioid agonist compound SNC-80, conformationally constrained analogs containing two diazatricyclodecane ring systems in place of dimethylpiperazine core motif were synthesized. The compounds showed subnanomolar or low nanomolar δ opioid receptor binding affinity. Depending upon the substituents on the diazatricyclodecane ring, these compounds displayed varying selectivity for δ opioid receptor over μ and κ receptors. Amongst the novel compounds, 1Aa showed the more interesting biological profile, with higher δ affinity and selectivity compared to SNC-80. The δ receptor agonist profile and antinociceptive activity of 1Aa were confirmed using ex-vivo (isolated mouse vas deferens) and in vivo (tail flick) assays.
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Affiliation(s)
- Giovanni Loriga
- C.N.R. Istituto di Farmacologia Traslazionale, UOS Cagliari, Edificio 5, Loc. Piscinamanna, 09010 Pula, CA, Italy.
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8
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He X, Sandhu HK, Yang Y, Hua F, Belser N, Kim DH, Xia Y. Neuroprotection against hypoxia/ischemia: δ-opioid receptor-mediated cellular/molecular events. Cell Mol Life Sci 2013; 70:2291-303. [PMID: 23014992 PMCID: PMC11113157 DOI: 10.1007/s00018-012-1167-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 09/08/2012] [Accepted: 09/10/2012] [Indexed: 12/24/2022]
Abstract
Hypoxic/ischemic injury remains the most dreaded cause of neurological disability and mortality. Despite the humbling experiences due to lack of promising therapy, our understanding of the complex cascades underlying the neuronal insult has led to advances in basic science research. One of the most noteworthy has been the effect of opioid receptors, especially the delta-opioid receptor (DOR), on hypoxic/ischemic neurons. Our recent studies, and those of others worldwide, present strong evidence that sheds light on DOR-mediated neuroprotection in the brain, especially in the cortex. The mechanisms of DOR neuroprotection are broadly categorized as: (1) stabilization of the ionic homeostasis, (2) inhibition of excitatory transmitter release, (3) attenuation of disrupted neuronal transmission, (4) increase in antioxidant capacity, (5) regulation of intracellular pathways-inhibition of apoptotic signals and activation of pro-survival signaling, (6) regulation of specific gene and protein expression, and (7) up-regulation of endogenous opioid release and/or DOR expression. Depending upon the severity and duration of hypoxic/ischemic insult, the release of endogenous opioids and DOR expression are regulated in response to the stress, and DOR signaling acts at multiple levels to confer neuronal tolerance to harmful insult. The phenomenon of DOR neuroprotection offers a potential clue for a promising target that may have significant clinical implications in our quest for neurotherapeutics.
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Affiliation(s)
- Xiaozhou He
- The Third Clinical College of Suzhou University, Changzhou, Jiangsu China
| | - Harleen K. Sandhu
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
| | - Yilin Yang
- The Third Clinical College of Suzhou University, Changzhou, Jiangsu China
| | - Fei Hua
- The Third Clinical College of Suzhou University, Changzhou, Jiangsu China
| | - Nathalee Belser
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
| | - Dong H. Kim
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
| | - Ying Xia
- The Vivian L Smith Department of Neurosurgery, The University of Texas Medical School at Houston, Houston, 77030 TX USA
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Fujii H, Takahashi T, Nagase H. Non-peptidic δ opioid receptor agonists and antagonists (2000 – 2012). Expert Opin Ther Pat 2013; 23:1181-208. [DOI: 10.1517/13543776.2013.804066] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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10
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Watanabe K, Kawaguchi M, Kitagawa K, Inoue S, Konishi N, Furuya H. Evaluation of the Neuroprotective Effect of Minocycline in a Rabbit Spinal Cord Ischemia Model. J Cardiothorac Vasc Anesth 2012; 26:1034-8. [DOI: 10.1053/j.jvca.2012.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Indexed: 11/11/2022]
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11
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Feng Y, He X, Yang Y, Chao D, Lazarus LH, Xia Y. Current research on opioid receptor function. Curr Drug Targets 2012; 13:230-46. [PMID: 22204322 DOI: 10.2174/138945012799201612] [Citation(s) in RCA: 197] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 08/09/2011] [Accepted: 08/12/2011] [Indexed: 12/11/2022]
Abstract
The use of opioid analgesics has a long history in clinical settings, although the comprehensive action of opioid receptors is still less understood. Nonetheless, recent studies have generated fresh insights into opioid receptor-mediated functions and their underlying mechanisms. Three major opioid receptors (μ-opioid receptor, MOR; δ-opioid receptor, DOR; and κ-opioid receptor, KOR) have been cloned in many species. Each opioid receptor is functionally sub-classified into several pharmacological subtypes, although, specific gene corresponding each of these receptor subtypes is still unidentified as only a single gene has been isolated for each opioid receptor. In addition to pain modulation and addiction, opioid receptors are widely involved in various physiological and pathophysiological activities, including the regulation of membrane ionic homeostasis, cell proliferation, emotional response, epileptic seizures, immune function, feeding, obesity, respiratory and cardiovascular control as well as some neurodegenerative disorders. In some species, they play an essential role in hibernation. One of the most exciting findings of the past decade is the opioid-receptor, especially DOR, mediated neuroprotection and cardioprotection. The upregulation of DOR expression and DOR activation increase the neuronal tolerance to hypoxic/ischemic stress. The DOR signal triggers (depending on stress duration and severity) different mechanisms at multiple levels to preserve neuronal survival, including the stabilization of homeostasis and increased pro-survival signaling (e.g., PKC-ERK-Bcl 2) and antioxidative capacity. In the heart, PKC and KATP channels are involved in the opioid receptor-mediated cardioprotection. The DOR-mediated neuroprotection and cardioprotection have the potential to significantly alter the clinical pharmacology in terms of prevention and treatment of life-threatening conditions like stroke and myocardial infarction. The main purpose of this article is to review the recent work done on opioids and their receptor functions. It shall provide an informative reference for better understanding the opioid system and further elucidation of the opioid receptor function from a physiological and pharmacological point of view.
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Affiliation(s)
- Yuan Feng
- Yale University School of Medicine, New Haven, CT, USA
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12
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Hwang J, Han JI, Han S. Effect of pretreatment with simvastatin on spinal cord ischemia-reperfusion injury in rats. J Cardiothorac Vasc Anesth 2012; 27:79-85. [PMID: 22445180 DOI: 10.1053/j.jvca.2012.01.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the pretreatment effect of simvastatin on spinal cord ischemia-reperfusion injury. DESIGN Prospective, interventional study. SETTING University research laboratory. PARTICIPANTS Forty-five male Sprague-Dawley rats. INTERVENTIONS Rats were treated with oral simvastatin, 10 mg/kg (simvastatin group; n = 15) or saline (control group; n = 15) for 5 days before ischemia. Spinal cord ischemia was induced using a balloon-tipped catheter placed in the proximal descending aorta in the control and simvastatin groups, but not in the sham group (n = 15). MEASUREMENTS AND MAIN RESULTS Neurologic function was assessed daily using the motor deficit index until 7 days after reperfusion. After the last neurologic evaluation, a histologic examination of the spinal cord was performed. At day 1 after reperfusion, the simvastatin group showed a significantly lower motor deficit index compared with the control group (2.0, 2.0-2.0, v 4.0, 3.5-5.0; p < 0.001). This trend was sustained at day 7 (2.0, 1.5-2.0, v 4.0, 3.0-4.0; p < 0.001). The simvastatin group displayed a significantly larger number of normal motor neurons compared with the control group (mean ± SD, 31.7 ± 6.1 v 20.4 ± 4.4; p < 0.001). However, compared with the sham group, the simvastatin group displayed fewer intact motor neurons (sham group, 38.5 ± 5.1; p = 0.005). CONCLUSIONS Pretreatment with simvastatin, 10 mg/kg, given orally for 5 days before the ischemia-reperfusion insult, improved the neurologic outcome and preserved more normal motor neurons compared with the control group in a rat model of spinal cord ischemia-reperfusion.
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Affiliation(s)
- Jinyoung Hwang
- Department of Anesthesiology and Pain Medicine, Seoul National University, Bundang Hospital, Seongnamsi, Gyeonggido, Korea
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13
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Effects of minocycline on hind-limb motor function and gray and white matter injury after spinal cord ischemia in rats. Spine (Phila Pa 1976) 2011; 36:1919-24. [PMID: 21304434 DOI: 10.1097/brs.0b013e3181ffda29] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A prospective, randomized laboratory investigation. OBJECTIVE To investigate whether administration of minocycline attenuates hind-limb motor dysfunction and gray and white matter injury after spinal cord ischemia. SUMMARY OF BACKGROUND DATA Minocycline, a semisynthetic tetracycline antibiotic, has been shown to have neuroprotective effects in models of focal and global cerebral ischemia. However, there have been no data available regarding the effects of minocycline in a model of spinal cord ischemia. METHODS Thirty-six rats were randomly allocated to one of three groups; control (C) group (n = 11), minocycline (M) group (n = 13), or sham group (n = 12). Minocycline or saline was intraperitoneally administered for 3 days beginning at 12 hours before 10 minutes of spinal cord ischemia or sham operation. Spinal cord ischemia was induced with intraaortic balloon catheter and blood withdrawal. Seventy-two hours after reperfusion, hind-limb motor functions were assessed using Basso, Beattie, Bresnahan (BBB) Scale (0 = paraplegia, 21 = normal). For histologic assessments, the gray and white matter injury was evaluated using the number of normal neurons and the extents of vacuolations in the white matter, respectively. Activated microglia was also evaluated using Iba-1 immunohistochemistry. RESULTS BBB scores and the numbers of normal neurons in the M group were significantly higher than those in the C group. The percentage areas of vacuolations in the white matter and the number of Iba-1 positive cells were significantly lower in the M group compared with those in the C group. CONCLUSION The results indicated that minocycline administration improved hind-limb motor function and attenuated gray and white matter injury and microglial activation after spinal cord ischemia in rats.
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14
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Turner SMF, Johnson SM. Delta-opioid receptor activation prolongs respiratory motor output during oxygen-glucose deprivation in neonatal rat spinal cord in vitro. Neuroscience 2011; 187:70-83. [PMID: 21571044 DOI: 10.1016/j.neuroscience.2011.04.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 03/31/2011] [Accepted: 04/29/2011] [Indexed: 10/18/2022]
Abstract
Delta opioid receptor (DOR) activation protects the adult mammalian brain during oxygen-glucose deprivation (OGD), but it is not known whether neonatal spinal motor circuits are also protected. Also, it is unclear whether the timing of spinal DOR activation relative to spinal OGD is important for neuroprotection. Thus, a split-bath in vitro neonatal rat brainstem/spinal cord preparation was used to record spontaneous respiratory motor output from cervical (C4-C5) and thoracic (T5-T6) ventral spinal roots while exposing only the spinal cord to OGD solution (0 mM glucose, bubbled with 95% N(2)/5% CO(2)) or DOR agonist drugs (DADLE, DPDPE). Spinal OGD solution application caused respiratory motor output frequency and amplitude to decrease until all activity was abolished (i.e. end-point times) after 25.9±1.4 min (cervical) and 25.2±1.4 min (thoracic). Spinal DOR activation via DPDPE (1.0 μM) prior-to and during spinal OGD increased cervical and thoracic end-point times to 35-48 min. Spinal DADLE or DPDPE (1.0 μM) application 15 min following spinal OGD onset increased cervical and thoracic end-point times to 36-45 min. Brief spinal DPDPE (1.0 μM) application for 10 min at 25 min before spinal OGD onset increased cervical and thoracic end-point times to 41-46 min. Overall, the selective DOR agonist, DPDPE, was more effective at increasing end-point times than DADLE. Naltrindole (DOR antagonist; 10 μM) pretreatment blocked DPDPE-dependent increase in end-point times, suggesting that DOR activation was required. Spinal naloxone (1.0 μM) application before and during spinal OGD also increased end-point times to 31-33 min, but end-point times were not altered by Mu opioid receptor (MOR) activation or DOR activation/MOR blockade, indicating that there are complex interactions between OGD and opioid signaling pathways. These data suggest DOR activation before, during, and after spinal OGD protects central motor networks and may provide neuroprotection during unpredictable perinatal ischemic events.
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Affiliation(s)
- S M F Turner
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
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15
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Johnson SM, Turner SMF. Protecting motor networks during perinatal ischemia: the case for delta-opioid receptors. Ann N Y Acad Sci 2010; 1198:260-70. [PMID: 20536941 DOI: 10.1111/j.1749-6632.2010.05434.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Perinatal ischemia is a common clinical problem with few successful therapies to prevent neuronal damage. Delta opioid receptor (DOR) activation is a versatile, evolutionarily conserved, endogenous neuroprotective mechanism that blocks several steps in the deleterious cascade of neurological events during ischemia. DOR activation prior to ischemia or severe hypoxia is neuroprotective in spinal motor networks, as well as cortical, cerebellar, and hippocampal neural networks. In addition to providing acute and long-lasting neuroprotection against ischemia, DOR activation appears to provide neuroprotection when given before, during, or following the onset of ischemia. Finally, DORs can be upregulated by several physiological and experimental perturbations. Potential adverse side effects affecting motor control, such as respiratory depression and seizures, are not well established in young mammals and may be mitigated by altering drug choice and method of drug administration. The unique features of DOR-dependent neuroprotection make it an attractive potential therapy that may be given to at-risk pregnant mothers shortly before delivery to provide long-lasting neuroprotection against unpredictable perinatal ischemic events.
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Affiliation(s)
- Stephen M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA.
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16
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Chao D, Xia Y. Ionic storm in hypoxic/ischemic stress: can opioid receptors subside it? Prog Neurobiol 2009; 90:439-70. [PMID: 20036308 DOI: 10.1016/j.pneurobio.2009.12.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 09/10/2009] [Accepted: 12/17/2009] [Indexed: 12/17/2022]
Abstract
Neurons in the mammalian central nervous system are extremely vulnerable to oxygen deprivation and blood supply insufficiency. Indeed, hypoxic/ischemic stress triggers multiple pathophysiological changes in the brain, forming the basis of hypoxic/ischemic encephalopathy. One of the initial and crucial events induced by hypoxia/ischemia is the disruption of ionic homeostasis characterized by enhanced K(+) efflux and Na(+)-, Ca(2+)- and Cl(-)-influx, which causes neuronal injury or even death. Recent data from our laboratory and those of others have shown that activation of opioid receptors, particularly delta-opioid receptors (DOR), is neuroprotective against hypoxic/ischemic insult. This protective mechanism may be one of the key factors that determine neuronal survival under hypoxic/ischemic condition. An important aspect of the DOR-mediated neuroprotection is its action against hypoxic/ischemic disruption of ionic homeostasis. Specially, DOR signal inhibits Na(+) influx through the membrane and reduces the increase in intracellular Ca(2+), thus decreasing the excessive leakage of intracellular K(+). Such protection is dependent on a PKC-dependent and PKA-independent signaling pathway. Furthermore, our novel exploration shows that DOR attenuates hypoxic/ischemic disruption of ionic homeostasis through the inhibitory regulation of Na(+) channels. In this review, we will first update current information regarding the process and features of hypoxic/ischemic disruption of ionic homeostasis and then discuss the opioid-mediated regulation of ionic homeostasis, especially in hypoxic/ischemic condition, and the underlying mechanisms.
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Affiliation(s)
- Dongman Chao
- Yale University School of Medicine, Department of Pediatrics, New Haven, CT 06520, USA
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17
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Delta opioid agonist [D-Ala2, D-Leu5] enkephalin (DADLE) reduced oxygen–glucose deprivation caused neuronal injury through the MAPK pathway. Brain Res 2009; 1292:100-6. [DOI: 10.1016/j.brainres.2009.06.104] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Revised: 06/18/2009] [Accepted: 06/22/2009] [Indexed: 12/29/2022]
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18
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Zhu M, Li MW, Tian XS, Ou XM, Zhu CQ, Guo JC. Neuroprotective role of delta-opioid receptors against mitochondrial respiratory chain injury. Brain Res 2008; 1252:183-91. [PMID: 19056363 DOI: 10.1016/j.brainres.2008.11.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Revised: 11/09/2008] [Accepted: 11/10/2008] [Indexed: 12/29/2022]
Abstract
It is recognized in recent years that activation of delta-opioid receptor (DOR) elicits neuroprotection against hypoxia and ischemia. However, the underlying mechanisms are not well understood yet. Mitochondrial dysfunction plays a key role in hypoxic neuronal injury, but the effect of DOR activation on neurons with a mitochondrial respiratory chain deficiency is poorly elucidated. In this study we tested the effects of DOR activation and inhibition on cultured cortical neurons after inhibiting mitochondrial respiratory chain with sodium azide (NaN(3)) in days 8 cultures. Neuronal injury was assessed by lactate dehydrogenase release. Changes in DOR proteins were investigated using an antibody against the N-terminus of the DOR, which recognizes the 60, 48, and 32 kDa proteins. Our main findings are that 1) delta- but not mu-opioid receptor activation reduces NaN(3)-induced neuronal damage, and this neuroprotective effect is abolished by DOR antagonist (naltrindole, NTI); 2) prolonged DOR inhibition with NTI further increases NaN(3)-induced neuronal damage; 3) NaN(3) treatment down-regulates DOR protein levels in neurons, and the 60 and 32 kDa proteins are particularly sensitive; 4) DADLE, besides activating DOR directly, also reverses the decrease of neuronal DOR protein levels induced by NaN(3), which may contribute greatly to its neuroprotective effect; 5) NTI reverses NaN(3)-induced down-regulation of DOR proteins as well, the effect of NTI amplifying NaN(3)-induced neuronal damage therefore is probably due to its inhibition on DOR activity only. In conclusion, these data suggest that DOR activation plays an important role in neuroprotection against mitochondrial respiratory chain injury.
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Affiliation(s)
- Min Zhu
- State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
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19
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Horiuchi T, Kawaguchi M, Kurita N, Inoue S, Sakamoto T, Nakamura M, Konishi N, Furuya H. Effects of delta-opioid agonist SNC80 on white matter injury following spinal cord ischemia in normothermic and mildly hypothermic rats. J Anesth 2008; 22:32-7. [PMID: 18306011 DOI: 10.1007/s00540-007-0576-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 09/03/2007] [Indexed: 11/29/2022]
Abstract
PURPOSE Although the delta-opioid agonist SNC80 has been shown to attenuate hind-limb motor function and gray matter injury in normothermic rats subjected to spinal cord ischemia (SCI), its effects on white matter injury remain undetermined. In the present study, we investigated whether SNC80 could attenuate white matter injury in normothermic and mildly hypothermic rats. METHODS Forty rats were randomly allocated to one of following five groups: vehicle or SNC80 with 10 min of SCI at 38 degrees C (V-38-10m or SNC-38-10m, respectively), vehicle or SNC80 with 22 min of SCI at 35 degrees C (V-35-22m or SNC-35-22m, respectively), or sham. SNC80 or vehicle was intrathecally administered 15 min before SCI. Forty-eight hours after reperfusion, the white matter injury was evaluated by the extent of vacuolation. RESULTS The percent area of vacuolation in the ventral white matter was significantly lower in the SNC-38-10m and SNC-35-22m groups compared with that in the V-38-10m and V-35-22m groups, respectively (P < 0.05). CONCLUSION The results indicate that intrathecal treatment with the delta-opioid agonist SNC80 can attenuate the ventral white matter injury following SCI in rats under normothermic and mildly hypothermic conditions.
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Affiliation(s)
- Toshinori Horiuchi
- Department of Anesthesiology, Nara Medical University, Kashihara, Nara, Japan
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20
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Iwata M, Inoue S, Kawaguchi M, Nakamura M, Konishi N, Furuya H. Effects of delta-opioid receptor stimulation and inhibition on hippocampal survival in a rat model of forebrain ischaemia. Br J Anaesth 2007; 99:538-46. [PMID: 17704092 DOI: 10.1093/bja/aem220] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND It has been reported that delta-opioid (DOP) receptor agonists may be neuroprotective in the central nervous system. However, the DOP agonist [d-Ala(2), d-Leu(5)]enkephalin (DADLE) does not produce neuroprotection in severe forebrain ischaemia. The aim of this study was to examine the effects of DADLE on hippocampal neurone survival against less severe forebrain ischaemia. METHODS Intraperitoneal injection of DADLE (0 or 16 mg kg(-1)) in male Sprague-Dawley rats was performed 30 min before ischaemia. Severe (10 min), moderate (8 min), or mild (6 min) forebrain ischaemia was produced by bilateral carotid occlusion combined with hypotension (35 mm Hg) under isoflurane (1.5%) anaesthesia. Naltrindole (10 mg kg(-1)) (DOP antagonist) was administered 30 min before DADLE in order to confirm DOP receptor activation in the neuroprotective efficacy of DADLE. Naltrindole alone was also administered 30 min before ischaemia to examine endogenous DOP agonism as a self-protecting mechanism against ischaemia. All animals were evaluated neurologically and histologically after a 1 week recovery period. RESULTS DADLE improved neurone survival in hippocampal CA3 and dentate gyrus (DG) sectors. CA1 neurones were not protected against moderate and mild ischaemia. Naltrindole abolished DADLE neuroprotection in the CA3 and DG after both moderate and mild ischaemia. Interestingly, regardless of co-administration of DADLE, naltrindole significantly worsened neuronal injury in the CA1 region after mild ischaemia. CONCLUSIONS These results suggest that DADLE provides limited neuroprotection to relatively ischaemia-resistant regions but not to selectively vulnerable regions. This was probably mediated by DOP stimulation. Pre-ischaemic treatment with a DOP antagonist, regardless of co-administration of DADLE, worsened neuronal damage at the selectively vulnerable regions only after mild forebrain ischaemia. These data suggest that DOP activation with endogenous DOP ligand may be involved in self-protecting ischaemia-sensitive regions of the brain.
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MESH Headings
- Animals
- Brain Ischemia/pathology
- Brain Ischemia/prevention & control
- Cell Survival/drug effects
- Drug Evaluation, Preclinical
- Enkephalin, Leucine-2-Alanine/pharmacology
- Enkephalin, Leucine-2-Alanine/therapeutic use
- Hippocampus/drug effects
- Hippocampus/pathology
- Male
- Naltrexone/analogs & derivatives
- Naltrexone/pharmacology
- Narcotic Antagonists/pharmacology
- Neurons/drug effects
- Neuroprotective Agents/pharmacology
- Neuroprotective Agents/therapeutic use
- Prosencephalon/blood supply
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/physiology
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Affiliation(s)
- M Iwata
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho Kashihara, Nara, Japan
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21
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Grau JW, Crown ED, Ferguson AR, Washburn SN, Hook MA, Miranda RC. Instrumental learning within the spinal cord: underlying mechanisms and implications for recovery after injury. ACTA ACUST UNITED AC 2007; 5:191-239. [PMID: 17099112 DOI: 10.1177/1534582306289738] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using spinally transected rats, research has shown that neurons within the L4-S2 spinal cord are sensitive to response-outcome (instrumental) relations. This learning depends on a form of N-methyl-D-aspartate (NMDA)-mediated plasticity. Instrumental training enables subsequent learning, and this effect has been linked to the expression of brain-derived neurotrophic factor. Rats given uncontrollable stimulation later exhibit impaired instrumental learning, and this deficit lasts up to 48 hr. The induction of the deficit can be blocked by prior training with controllable shock, the concurrent presentation of a tonic stimulus that induces antinociception, or pretreatment with an NMDA or gamma-aminobutyric acid-A antagonist. The expression of the deficit depends on a kappa opioid. Uncontrollable stimulation enhances mechanical reactivity (allodynia), and treatments that induce allodynia (e.g., inflammation) inhibit learning. In intact animals, descending serotonergic neurons exert a protective effect that blocks the adverse consequences of uncontrollable stimulation. Uncontrollable, but not controllable, stimulation impairs the recovery of function after a contusion injury.
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Affiliation(s)
- James W Grau
- Department of Psychology, Texas A&M University, College Station, TX 77843-4235, USA.
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22
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Iwata M, Inoue S, Kawaguchi M, Kurita N, Horiuchi T, Nakamura M, Konishi N, Furuya H. Delta opioid receptors stimulation with [D-Ala2, D-Leu5] enkephalin does not provide neuroprotection in the hippocampus in rats subjected to forebrain ischemia. Neurosci Lett 2006; 414:242-6. [PMID: 17207574 DOI: 10.1016/j.neulet.2006.12.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 12/14/2006] [Accepted: 12/15/2006] [Indexed: 11/18/2022]
Abstract
It has been reported that delta opioid agonists can have neuroprotective efficacy in the central nervous system. This study was conducted to test the hypothesis that a delta opioid receptor (DOR) agonist, [D-Ala2, D-Leu5] enkephalin (DADLE), can improve neuron survival against experimental forebrain ischemia in rats. Using male rats (n=125), intraperitoneal injection of DADLE (0, 0.25, 1, 4, 16 mg kg-1) was performed 30 min before ischemia. Ten minutes interval forebrain ischemia was provided by the bilateral carotid occlusion combined with hypotension (35 mm Hg) under isoflurane (1.5%) anesthesia. All animals were neurologically and histologically evaluated after a recovery period of 1 week. As histological evaluation, percentages of ischemic neurons in the CA1, CA3, dentate gyrus (DG) were measured. During the recovery period, 27 rats died because of apparent upper airway obstruction, seizure, or unidentified causes. There were no differences in the motor activity score among the groups. Ten minutes forebrain ischemia induced approximately 75, 20, and 10% neuronal death in the CA1, CA3, and DG, respectively. Any doses of DADLE did not attenuate neuronal injury in the hippocampus after ischemia. Pre-ischemic treatment of DORs agonism with DADLE did not provide any neuroprotection to the hippocampus in rats subjected to forebrain ischemia.
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MESH Headings
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/therapeutic use
- Animals
- Brain Ischemia/drug therapy
- Brain Ischemia/metabolism
- Brain Ischemia/physiopathology
- Cell Survival/drug effects
- Cell Survival/physiology
- Cerebral Infarction/drug therapy
- Cerebral Infarction/physiopathology
- Cerebral Infarction/prevention & control
- Dentate Gyrus/drug effects
- Dentate Gyrus/metabolism
- Dentate Gyrus/physiopathology
- Dose-Response Relationship, Drug
- Enkephalin, Leucine-2-Alanine/pharmacology
- Enkephalin, Leucine-2-Alanine/therapeutic use
- Hippocampus/drug effects
- Hippocampus/metabolism
- Hippocampus/physiopathology
- Male
- Nerve Degeneration/drug therapy
- Nerve Degeneration/physiopathology
- Nerve Degeneration/prevention & control
- Neuroprotective Agents/pharmacology
- Neuroprotective Agents/therapeutic use
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/metabolism
- Treatment Failure
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Affiliation(s)
- Masato Iwata
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho Kashihara, Nara 634-8522, Japan
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Trabanco AA, Pullan S, Alonso JM, Alvarez RM, Andrés JI, Boeckx I, Fernández J, Gómez A, Iturrino L, Janssens FE, Leenaerts JE, De Lucas AI, Matesanz E, Meert T, Steckler T. 4-Phenyl-4-[1H-imidazol-2-yl]-piperidine derivatives, a novel class of selective δ-opioid agonists. Bioorg Med Chem Lett 2006; 16:146-9. [PMID: 16236510 DOI: 10.1016/j.bmcl.2005.09.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 09/06/2005] [Accepted: 09/12/2005] [Indexed: 01/01/2023]
Abstract
A novel series of 4-phenyl-4-[1H-imidazol-2-yl]-piperidine derivatives has been prepared and their synthesis described herein. In vitro affinities for delta-, mu-, and kappa-opioid receptors, as well as the functional activity in the [(35)S]GTPgammaS assay are reported. The most potent and selective delta-opioid agonist 18a exhibited a K(i) of 18 nM, and was >258-fold and 28-fold selective over mu- and kappa-receptors, respectively; the compound is a full agonist with an EC(50) value of 14 nM.
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Affiliation(s)
- Andrés A Trabanco
- Division of Psychiatry, Research and Early Development Europe, Johnson and Johnson Pharmaceutical Research and Development, Jarama 75, 47007 Toledo, Spain.
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Abstract
This paper is the 27th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over 30 years of research. It summarizes papers published during 2004 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, USA.
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