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Blaine AT, van Rijn RM. Receptor expression and signaling properties in the brain, and structural ligand motifs that contribute to delta opioid receptor agonist-induced seizures. Neuropharmacology 2023; 232:109526. [PMID: 37004753 PMCID: PMC11078570 DOI: 10.1016/j.neuropharm.2023.109526] [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: 08/02/2022] [Revised: 03/10/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The δ opioid receptor (δOR) is a therapeutic target for the treatment of various neurological disorders, such as migraines, chronic pain, alcohol use, and mood disorders. Relative to μ opioid receptor agonists, δOR agonists show lower abuse liability and may be potentially safer analgesic alternatives. However, currently no δOR agonists are approved for clinical use. A small number of δOR agonists reached Phase II trials, but ultimately failed to progress due to lack of efficacy. One side effect of δOR agonism that remains poorly understood is the ability of δOR agonists to produce seizures. The lack of a clear mechanism of action is partly driven by the fact that δOR agonists range in their propensity to induce seizure behavior, with multiple δOR agonists reportedly not causing seizures. There is a significant gap in our current understanding of why certain δOR agonists are more likely to induce seizures, and what signal-transduction pathway and/or brain area is engaged to produce these seizures. In this review we provide a comprehensive overview of the current state of knowledge of δOR agonist-mediated seizures. The review was structured to highlight which agonists produce seizures, which brain regions have been implicated and which signaling mediators have been examined in this behavior. Our hope is that this review will spur future studies that are carefully designed and aimed to solve the question why certain δOR agonists are seizurogenic. Obtaining such insight may expedite the development of novel δOR clinical candidates without the risk of inducing seizures. This article is part of the Special Issue on "Opioid-induced changes in addiction and pain circuits".
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Affiliation(s)
- Arryn T Blaine
- Purdue University, Department of Medicinal Chemistry and Molecular Pharmacology, West Lafayette, IN, 47907, USA; Purdue University Interdisciplinary Life Science graduate program, West Lafayette, IN, 47907, USA
| | - Richard M van Rijn
- Purdue University, Department of Medicinal Chemistry and Molecular Pharmacology, West Lafayette, IN, 47907, USA; Purdue Institute for Integrative Neuroscience, West Lafayette, IN, 47907, USA; Purdue Institute for Drug Discovery, West Lafayette, IN, 47907, USA; Septerna Inc., South San Francisco, CA, 94080, USA.
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Neugebauer V, Presto P, Yakhnitsa V, Antenucci N, Mendoza B, Ji G. Pain-related cortico-limbic plasticity and opioid signaling. Neuropharmacology 2023; 231:109510. [PMID: 36944393 PMCID: PMC10585936 DOI: 10.1016/j.neuropharm.2023.109510] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 03/23/2023]
Abstract
Neuroplasticity in cortico-limbic circuits has been implicated in pain persistence and pain modulation in clinical and preclinical studies. The amygdala has emerged as a key player in the emotional-affective dimension of pain and pain modulation. Reciprocal interactions with medial prefrontal cortical regions undergo changes in pain conditions. Other limbic and paralimbic regions have been implicated in pain modulation as well. The cortico-limbic system is rich in opioids and opioid receptors. Preclinical evidence for their pain modulatory effects in different regions of this highly interactive system, potentially opposing functions of different opioid receptors, and knowledge gaps will be described here. There is little information about cell type- and circuit-specific functions of opioid receptor subtypes related to pain processing and pain-related plasticity in the cortico-limbic system. The important role of anterior cingulate cortex (ACC) and amygdala in MOR-dependent analgesia is most well-established, and MOR actions in the mesolimbic system appear to be similar but remain to be determined in mPFC regions other than ACC. Evidence also suggests that KOR signaling generally serves opposing functions whereas DOR signaling in the ACC has similar, if not synergistic effects, to MOR. A unifying picture of pain-related neuronal mechanisms of opioid signaling in different elements of the cortico-limbic circuitry has yet to emerge. This article is part of the Special Issue on "Opioid-induced changes in addiction and pain circuits".
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Affiliation(s)
- Volker Neugebauer
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Peyton Presto
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Vadim Yakhnitsa
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Nico Antenucci
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Brianna Mendoza
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Guangchen Ji
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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Blaine AT, Miao Y, Yuan J, Palant S, Liu RJ, Zhang ZY, van Rijn RM. Exploration of beta-arrestin isoform signaling pathways in delta opioid receptor agonist-induced convulsions. Front Pharmacol 2022; 13:914651. [PMID: 36059958 PMCID: PMC9428791 DOI: 10.3389/fphar.2022.914651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/13/2022] [Indexed: 11/17/2022] Open
Abstract
The δ-opioid receptor (δOR) has been considered as a therapeutic target in multiple neurological and neuropsychiatric disorders particularly as δOR agonists are deemed safer alternatives relative to the more abuse-liable µ-opioid receptor drugs. Clinical development of δOR agonists, however, has been challenging in part due to the seizure-inducing effects of certain δOR agonists. Especially agonists that resemble the δOR-selective agonist SNC80 have well-established convulsive activity. Close inspection suggests that many of those seizurogenic δOR agonists efficaciously recruit β-arrestin, yet surprisingly, SNC80 displays enhanced seizure activity in β-arrestin 1 knockout mice. This finding led us to hypothesize that perhaps β-arrestin 1 is protective against, whereas β-arrestin 2 is detrimental for δOR-agonist-induced seizures. To investigate our hypothesis, we characterized three different δOR agonists (SNC80, ADL5859, ARM390) in cellular assays and in vivo in wild-type and β-arrestin 1 and β-arrestin 2 knockout mice for seizure activity. We also investigated downstream kinases associated with β-arrestin-dependent signal transduction. We discovered that δOR agonist-induced seizure activity strongly and positively correlates with β-arrestin 2 efficacy for the agonist, but that indirect inhibition of ERK activation using the MEK inhibitor SL327 did not inhibit seizure potency and duration. Inhibition of the PI3K/AKT/mTOR signaling with honokiol but not PQR530, attenuated SNC80 seizure duration in β-arrestin 1 knockout, but honokiol did not reduce SNC80-induced seizures in wild-type mice. Ultimately, our results indicate that β-arrestin 2 is correlated with δOR agonist-induced seizure intensity, but that global β-arrestin 1 knockout mice are a poor model system to investigate their mechanism of action.
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Affiliation(s)
- Arryn T. Blaine
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
- Purdue Interdisciplinary Life Sciences Graduate Program, West Lafayette, IN, United States
| | - Yiming Miao
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
| | - Jinling Yuan
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
| | - Sophia Palant
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
| | - Rebecca J. Liu
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
| | - Zhong-Yin Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
- Purdue Institute for Drug Discovery, West Lafayette, IN, United States
- Purdue University Cancer Center, West Lafayette, IN, United States
| | - Richard. M. van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
- Purdue Institute for Drug Discovery, West Lafayette, IN, United States
- Purdue University Cancer Center, West Lafayette, IN, United States
- Purdue Institute for Integrative Neuroscience, West Lafayette, IN, United States
- *Correspondence: Richard. M. van Rijn,
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4
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Integrative opioid-GABAergic neuronal mechanisms regulating dopamine efflux in the nucleus accumbens of freely moving animals. Pharmacol Rep 2021; 73:971-983. [PMID: 33743175 DOI: 10.1007/s43440-021-00249-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/26/2021] [Accepted: 03/11/2021] [Indexed: 01/14/2023]
Abstract
The nucleus accumbens (NAc) is a terminal region of mesocorticolimbic dopamine (DA) neuronal projections from the ventral tegmental area. Accumbal DA release is integrated by afferents from other brain regions and by interneurons, which involve a diversity of neurotransmitters and neuropeptides. These integrative processes, implicated in the pathobiology of neuropsychiatric disorders, are mediated via receptor subtypes whose relative roles in the regulation of accumbal DA release are poorly understood. Such complex interactions are exemplified by how selective activation of opioid receptor subtypes enhances accumbal DA efflux in a manner that is modulated by changes in neural activity through GABA receptor subtypes. This review delineates the roles of GABAA and GABAB receptors in GABAergic neural mechanisms in NAc that participate in delta- and mu-opioid receptor-mediated increases in accumbal DA efflux in freely moving rats, focusing on studies using in vivo brain microdialysis. First, we consider how endogenous GABA exerts inhibition of accumbal DA efflux through GABA receptor subtypes. We also consider possible intra-neuronal source of the endogenous GABA that inhibits accumbal DA efflux. As NAc contains GABAergic neurons that express delta- or mu-opioid receptors, inhibition of accumbal GABAergic neurons is a candidate for mediating delta- or mu-opioid receptor-mediated increases in accumbal DA efflux. Therefore, we provide a detailed analysis of the effects of GABA receptor subtype ligands on delta- and mu-opioid receptor-mediated accumbal DA efflux. Finally, we present an integrative model to explain the mechanisms of interaction among delta- and mu-opioid receptors, GABAergic neurons and DAergic neurons in NAc.
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Li H, Kuninobu Y. Palladium‐Catalyzed Secondary C(
sp
3
)−H Arylation of 2‐Alkylpyridines. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000306] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Hong‐Liang Li
- Institute for Molecular Design and Synthesis, School of Pharmaceutical Science and TechnologyTianjin University 92Weijin Road, Nankai District Tianjin 300072 People's Republic of China
| | - Yoichiro Kuninobu
- Institute for Materials Chemistry and EngineeringKyushu University 6-1 Kasugakoen, Kasuga-shi Fukuoka 816-8580 Japan
- Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering SciencesKyushu University 6-1 Kasugakoen, Kasuga-shi Fukuoka 816-8580 Japan
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6
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Smith KL, Cunningham JI, Eyerman DJ, Dean RL, Deaver DR, Sanchez C. Opioid system modulators buprenorphine and samidorphan alter behavior and extracellular neurotransmitter concentrations in the Wistar Kyoto rat. Neuropharmacology 2019; 146:316-326. [DOI: 10.1016/j.neuropharm.2018.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/26/2018] [Accepted: 11/10/2018] [Indexed: 01/04/2023]
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7
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Demin KA, Meshalkina DA, Kysil EV, Antonova KA, Volgin AD, Yakovlev OA, Alekseeva PA, Firuleva MM, Lakstygal AM, de Abreu MS, Barcellos LJG, Bao W, Friend AJ, Amstislavskaya TG, Rosemberg DB, Musienko PE, Song C, Kalueff AV. Zebrafish models relevant to studying central opioid and endocannabinoid systems. Prog Neuropsychopharmacol Biol Psychiatry 2018; 86:301-312. [PMID: 29604314 DOI: 10.1016/j.pnpbp.2018.03.024] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/26/2018] [Accepted: 03/26/2018] [Indexed: 12/19/2022]
Abstract
The endocannabinoid and opioid systems are two interplaying neurotransmitter systems that modulate drug abuse, anxiety, pain, cognition, neurogenesis and immune activity. Although they are involved in such critical functions, our understanding of endocannabinoid and opioid physiology remains limited, necessitating further studies, novel models and new model organisms in this field. Zebrafish (Danio rerio) is rapidly emerging as one of the most effective translational models in neuroscience and biological psychiatry. Due to their high physiological and genetic homology to humans, zebrafish may be effectively used to study the endocannabinoid and opioid systems. Here, we discuss current models used to target the endocannabinoid and opioid systems in zebrafish, and their potential use in future translational research and high-throughput drug screening. Emphasizing the high degree of conservation of the endocannabinoid and opioid systems in zebrafish and mammals, we suggest zebrafish as an excellent model organism to study these systems and to search for the new drugs and therapies targeting their evolutionarily conserved mechanisms.
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Affiliation(s)
- Konstantin A Demin
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia; Laboratory of Preclinical Bioscreening, Russian Research Center for Radiology and Surgical Technologies, Ministry of Health, St. Petersburg, Russia
| | - Darya A Meshalkina
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia; Laboratory of Preclinical Bioscreening, Russian Research Center for Radiology and Surgical Technologies, Ministry of Health, St. Petersburg, Russia
| | - Elana V Kysil
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia
| | - Kristina A Antonova
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia
| | - Andrey D Volgin
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Medical Military Academy, St. Petersburg, Russia
| | - Oleg A Yakovlev
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Medical Military Academy, St. Petersburg, Russia
| | - Polina A Alekseeva
- Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia
| | - Maria M Firuleva
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia
| | - Anton M Lakstygal
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia
| | - Murilo S de Abreu
- Bioscience Institute, University of Passo Fundo (UPF), Passo Fundo, RS, Brazil; Graduate Program in Pharmacology, Federal University of Santa Maria, Santa Maria, Brazil
| | - Leonardo J G Barcellos
- Graduate Program in Pharmacology, Federal University of Santa Maria, Santa Maria, Brazil; Graduate Programs in Environmental Sciences, and Bio-Experimentation, University of Passo Fundo (UPF), Passo Fundo, Brazil; The International Zebrafish Neuroscience Research Consortium (ZNRC), Slidell, LA, USA
| | - Wandong Bao
- School of Pharmacy, Southwest University, Chongqing, China
| | - Ashton J Friend
- The International Zebrafish Neuroscience Research Consortium (ZNRC), Slidell, LA, USA; Tulane University School of Science and Engineering, New Orleans, LA, USA
| | - Tamara G Amstislavskaya
- The International Zebrafish Neuroscience Research Consortium (ZNRC), Slidell, LA, USA; Laboratory of Translational Biopsychiatry, Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia; Neuroscience Department, Novosibirsk State University, Novosibirsk, Russia
| | - Denis B Rosemberg
- The International Zebrafish Neuroscience Research Consortium (ZNRC), Slidell, LA, USA; Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria, Brazil
| | - Pavel E Musienko
- Laboratory of Neuroprosthetics, Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia; Laboratory of Motor Physiology, Pavlov Institute of Physiology RAS, St. Petersburg, Russia; Laboratory of Neurophysiology and Experimental Neurorehabilitation, St. Petersburg State Research Institute of Phthysiopulmonology, Ministry of Health, St. Petersburg, Russia; Russian Research Center of Radiology and Surgical Technologies, Ministry of Health, St. Petersburg, Russia
| | - Cai Song
- Research Institute for Marine Drugs and Nutrition, Guangdong Ocean University, Zhanjiang, China; Marine Medicine Research and Development Center, Shenzhen Institute of Guangdong Ocean University, Shenzhen, China
| | - Allan V Kalueff
- School of Pharmacy, Southwest University, Chongqing, China; Laboratory of Translational Biopsychiatry, Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia; Neuroscience Department, Novosibirsk State University, Novosibirsk, Russia; ZENEREI Research Center, Slidell, LA, USA; Russian Research Center of Radiology and Surgical Technologies, Ministry of Health, St. Petersburg, Russia; Ural Federal University, Ekaterinburg, Russia; Aquatic Laboratory, Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia.
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8
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Watanabe Y, Aono Y, Komiya M, Waddington JL, Saigusa T. Stimulation of accumbal GABA B receptors inhibits delta1- and delta2-opioid receptor-mediated dopamine efflux in the nucleus accumbens of freely moving rats. Eur J Pharmacol 2018; 837:88-95. [PMID: 30086266 DOI: 10.1016/j.ejphar.2018.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/29/2023]
Abstract
The nucleus accumbens contains delta-opioid receptors that may decrease inhibitory neurotransmission. As GABAB receptors inhibit dopamine release, decrease in activation of GABAB receptors may be a mediator of delta-opioid receptor-induced accumbal dopamine efflux. If so, accumbal dopamine efflux induced by delta-opioid receptor activation should be suppressed by stimulating GABAB receptors. As delta-opioid receptors are further subdivided into delta1- and delta2-opioid receptors, we analysed the effects of the GABAB receptor agonist baclofen on delta1- and delta2-opioid receptor-mediated accumbal dopamine efflux in freely moving rats using in vivo microdialysis. Drugs were applied intracerebrally through the dialysis probe. Doses of compounds show total amount administered (mol) during 25-50 min infusions. Baclofen (2.5 and 5.0 nmol), which did not alter basal dopamine levels, inhibited the delta1-opioid receptor agonist DPDPE (5.0 nmol)-induced dopamine efflux. Baclofen (2.5 and 5.0 nmol) also inhibited the delta2-opioid receptor agonist deltorphin II (25.0 nmol)-induced dopamine efflux. A low dose of the GABAB receptor antagonist 2-hydroxysaclofen (100.0 pmol), which failed to alter basal accumbal dopamine levels, counteracted the inhibitory effects of baclofen (5.0 nmol) on DPDPE (5.0 nmol)- and deltorphin II (25.0 nmol)-induced dopamine efflux. The present results show that reduction in accumbal GABAB receptor-mediated inhibition of accumbal dopaminergic activity facilitates activation of delta1- and delta2-opioid receptor-induced increases in accumbal dopamine efflux. This study suggests that activation of delta1- and delta2-opioid receptors on the cell bodies and/or terminals of accumbal GABAergic interneurons inhibits GABA release and, accordingly, decreases GABAB receptor-mediated inhibition of dopaminergic terminals, resulting in enhanced accumbal dopamine efflux.
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Affiliation(s)
- Yuriko Watanabe
- Department of Oral Surgery, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan; Nihon University Graduate School of Dentistry at Matsudo, Oral Surgery, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan
| | - Yuri Aono
- Department of Pharmacology, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan
| | - Masamichi Komiya
- Department of Oral Surgery, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan
| | - John L Waddington
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, St. Stephen's Green, Dublin 2, Ireland
| | - Tadashi Saigusa
- Department of Pharmacology, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan.
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Saigusa T, Aono Y, Waddington JL. Mechanisms underlying δ- and μ-opioid receptor agonist-induced increases in extracellular dopamine level in the nucleus accumbens of freely moving rats. J Oral Sci 2018. [PMID: 28637978 DOI: 10.2334/josnusd.16-0874] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The nucleus accumbens is a terminal area of the mesolimbic dopaminergic system that arises in the ventral tegmental area. Opioids are thought to enhance dopaminergic activity in the nucleus accumbens by activating δ- and μ-opioid receptors in the ventral tegmental area. However, δ- and μ-opioid receptor agonists increase extracellular levels of accumbal dopamine when infused directly into the nucleus accumbens of rats. Therefore, the roles of δ- and μ-opioid receptors in regulation of accumbal dopaminergic neural activity have been analyzed by using δ- and μ-opioid receptor ligands. This review describes the mechanisms underlying the stimulatory effects on accumbal dopamine efflux, which are induced by local administration of δ- and μ-opioid receptor agonists into the nucleus accumbens of freely moving rats. The focus of this article is neurochemical studies that use in vivo microdialysis techniques. Taken together, the in vivo neurochemical evidence from these studies indicates that δ- and μ-opioid receptor agonists increase accumbal dopamine efflux by activating naloxone-sensitive opioid receptors, and by mechanisms independent of naloxone-sensitive opioid receptors, in the nucleus accumbens.
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Affiliation(s)
- Tadashi Saigusa
- Department of Pharmacology, Nihon University School of Dentistry at Matsudo
| | - Yuri Aono
- Department of Pharmacology, Nihon University School of Dentistry at Matsudo
| | - John L Waddington
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland
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Stimulation of accumbal GABA A receptors inhibits delta2-, but not delta1-, opioid receptor-mediated dopamine efflux in the nucleus accumbens of freely moving rats. Eur J Pharmacol 2017; 815:18-25. [PMID: 28923348 DOI: 10.1016/j.ejphar.2017.09.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/06/2017] [Accepted: 09/14/2017] [Indexed: 11/23/2022]
Abstract
The nucleus accumbens contains delta-opioid receptors that may reduce inhibitory neurotransmission. Reduction in GABAA receptor-mediated inhibition of accumbal dopamine release due to delta-opioid receptor activation should be suppressed by stimulating accumbal GABAA receptors. As delta-opioid receptors are divided into delta2- and delta1-opioid receptors, we analysed the effects of the GABAA receptor agonist muscimol on delta2- and delta1-opioid receptor-mediated accumbal dopamine efflux in freely moving rats using in vivo microdialysis. Drugs were administered intracerebrally through the dialysis probe. Doses of compounds indicate total amount administered (mol) during 25-50min infusions. The delta2-opioid receptor agonist deltorphin II (25.0nmol)- and delta1-opioid receptor agonist DPDPE (5.0nmol)-induced increases in dopamine efflux were inhibited by the delta2-opioid receptor antagonist naltriben (1.5nmol) and the delta1-opioid receptor antagonist BNTX (150.0pmol), respectively. Muscimol (250.0pmol) inhibited deltorphin II (25.0nmol)-induced dopamine efflux. The GABAA receptor antagonist bicuculline (50.0pmol), which failed to affect deltorphin II (25.0nmol)-induced dopamine efflux, counteracted the inhibitory effect of muscimol on deltorphin II-induced dopamine efflux. Neither muscimol (250.0pmol) nor bicuculline (50.0 and 500.0pmol) altered DPDPE (5.0nmol)-induced dopamine efflux. The present results show that reduction in accumbal GABAA receptor-mediated inhibition of dopaminergic activity is necessary to produce delta2-opioid receptor-induced increase in accumbal dopamine efflux. This study indicates that activation of delta2- but not delta1-opioid receptors on the cell bodies and/or terminals of accumbal GABAergic interneurons inhibits GABA release and, accordingly, decreases GABAA receptor-mediated inhibition of dopaminergic terminals, resulting in enhanced accumbal dopamine efflux.
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11
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Kiguchi Y, Aono Y, Watanabe Y, Yamamoto-Nemoto S, Shimizu K, Shimizu T, Kosuge Y, Waddington JL, Ishige K, Ito Y, Saigusa T. In vivo neurochemical evidence that delta1-, delta2- and mu2-opioid receptors, but not mu1-opioid receptors, inhibit acetylcholine efflux in the nucleus accumbens of freely moving rats. Eur J Pharmacol 2016; 789:402-410. [DOI: 10.1016/j.ejphar.2016.07.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 06/09/2016] [Accepted: 07/16/2016] [Indexed: 11/16/2022]
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Rose JH, Karkhanis AN, Steiniger-Brach B, Jones SR. Distinct Effects of Nalmefene on Dopamine Uptake Rates and Kappa Opioid Receptor Activity in the Nucleus Accumbens Following Chronic Intermittent Ethanol Exposure. Int J Mol Sci 2016; 17:ijms17081216. [PMID: 27472317 PMCID: PMC5000614 DOI: 10.3390/ijms17081216] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 12/13/2022] Open
Abstract
The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs.
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Affiliation(s)
- Jamie H Rose
- Department of Physiology and Pharmacology Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | - Anushree N Karkhanis
- Department of Physiology and Pharmacology Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
| | | | - Sara R Jones
- Department of Physiology and Pharmacology Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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Richards EM, Mathews DC, Luckenbaugh DA, Ionescu DF, Machado-Vieira R, Niciu MJ, Duncan WC, Nolan NM, Franco-Chaves JA, Hudzik T, Maciag C, Li S, Cross A, Smith MA, Zarate CA. A randomized, placebo-controlled pilot trial of the delta opioid receptor agonist AZD2327 in anxious depression. Psychopharmacology (Berl) 2016; 233:1119-30. [PMID: 26728893 PMCID: PMC5103283 DOI: 10.1007/s00213-015-4195-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/14/2015] [Indexed: 12/20/2022]
Abstract
RATIONALE Patients with anxious major depressive disorder (AMDD) have more severe symptoms and poorer treatment response than patients with non-AMDD. Increasing evidence implicates the endogenous opioid system in the pathophysiology of depression. AZD2327 is a selective delta opioid receptor (DOR) agonist with anxiolytic and antidepressant activity in animal models. OBJECTIVE This double-blind, parallel group design, placebo-controlled pilot study evaluated the safety and efficacy of AZD2327 in a preclinical model and in patients with AMDD. METHODS We initially tested the effects of AZD2327 in an animal model of AMDD. Subsequently, 22 subjects with AMDD were randomized to receive AZD2327 (3 mg BID) or placebo for 4 weeks. Primary outcome measures included the Hamilton Depression Rating Scale (HAM-D) and the Hamilton Anxiety Rating Scale (HAM-A). We also evaluated neurobiological markers implicated in mood and anxiety disorders, including vascular endothelial growth factor (VEGF) and electroencephalogram (EEG). RESULTS Seven (54 %) patients responded to active drug and three (33 %) responded to placebo. No significant main drug effect was found on either the HAM-D (p = 0.39) or the HAM-A (p = 0.15), but the HAM-A had a larger effect size. Levels of AZ12311418, a major metabolite of AZD2327, were higher in patients with an anti-anxiety response to treatment compared to nonresponders (p = 0.03). AZD2327 treatment decreased VEGF levels (p = 0.02). There was a trend (p < 0.06) for those with an anti-anxiety response to have higher EEG gamma power than nonresponders. CONCLUSION These results suggest that AZD2327 has larger potential anxiolytic than antidepressant efficacy. Additional research with DOR agonists should be considered.
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Affiliation(s)
- Erica M Richards
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA.
| | - Daniel C Mathews
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
- Lundbeck LLC, Chicago, IL, USA
| | - David A Luckenbaugh
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
| | - Dawn F Ionescu
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
- Massachusetts General Hospital, Boston, MA, USA
| | - Rodrigo Machado-Vieira
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
| | - Mark J Niciu
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
| | - Wallace C Duncan
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
| | - Neal M Nolan
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
| | - Jose A Franco-Chaves
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
- Veteran Affairs Caribbean Healthcare System, San Juan, Puerto Rico
| | - Thomas Hudzik
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
- AbbVie, Chicago, IL, USA
| | - Carla Maciag
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
- Sage Therapeutics, Cambridge, MA, USA
| | - Shuang Li
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - Alan Cross
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - Mark A Smith
- AstraZeneca Neuroscience Innovative Medicines, Cambridge, MA, USA
| | - Carlos A Zarate
- Experimental Therapeutics and Pathophysiology Branch, Department of Health and Human Services, National Institute of Mental Health, National Institutes of Health, 10 Center Drive CRC, Room 7-5545, Bethesda, MD, 20892, USA
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Peppin JF, Raffa RB. Delta opioid agonists: a concise update on potential therapeutic applications. J Clin Pharm Ther 2015; 40:155-66. [PMID: 25726896 DOI: 10.1111/jcpt.12244] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/24/2014] [Indexed: 01/23/2023]
Abstract
WHAT IS KNOWN AND OBJECTIVE The endogenous opioid system co-evolved with chemical defences, or at times symbiotic relationships, between plants and other autotrophs and heterotrophic predators - thus, it is not surprising that endogenous opioid ligands and exogenous mimetic ligands produce diverse physiological effects. Among the endogenous opioid peptides (endomorphins, enkephalins, dynorphins and nociception/orphanin FQ) derived from the precursors encoded by four genes (PNOC, PENK, PDYN and POMC) are the pentapeptides Met-enkephalin (Tyr-Gly-Gly-Phe-Met) and Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu). The physiological effects of the enkephalins are mediated via 7-transmembrane G protein-coupled receptors, including delta opioid receptor (DOR). We present a concise update on the status of progress and opportunities of this approach. METHODS A literature search of the PUBMED database and a combination of keywords including delta opioid receptor, analgesia, mood and individual compounds identified therein, from industry and other source, and from www.clinicaltrials.com. RESULTS AND DISCUSSION DOR agonist and antagonist ligands have been developed with ever increasing affinity and selectivity for DOR over other opioid receptor subtypes and studied for therapeutic utility, primarily for pain relief, but also for other clinical endpoints. WHAT IS NEW AND CONCLUSION Selective DOR agonists have been designed with a large increase in therapeutic window for a variety of potential CNS applications including pain, depression, and learning and memory among others.
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Affiliation(s)
- J F Peppin
- Center for Bioethics, Pain Management and Medicine, University City, MO, USA; Mallinckrodt Pharmaceuticals, Hazelwood, MO, USA
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15
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Aono Y, Saigusa T, Taguchi H, Uchida T, Takada K, Koshikawa N, Cools AR. Synergistic, but not separate, stimulation of accumbal β1- and β2-adrenoceptors alters the accumbal dopamine efflux in freely moving rats. Eur J Pharmacol 2013; 715:363-9. [DOI: 10.1016/j.ejphar.2013.04.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 04/19/2013] [Accepted: 04/26/2013] [Indexed: 12/22/2022]
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Yoo JH, Kitchen I, Bailey A. The endogenous opioid system in cocaine addiction: what lessons have opioid peptide and receptor knockout mice taught us? Br J Pharmacol 2012; 166:1993-2014. [PMID: 22428846 DOI: 10.1111/j.1476-5381.2012.01952.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Cocaine addiction has become a major concern in the UK as Britain tops the European 'league table' for cocaine abuse. Despite its devastating health and socio-economic consequences, no effective pharmacotherapy for treating cocaine addiction is available. Identifying neurochemical changes induced by repeated drug exposure is critical not only for understanding the transition from recreational drug use towards compulsive drug abuse but also for the development of novel targets for the treatment of the disease and especially for relapse prevention. This article focuses on the effects of chronic cocaine exposure and withdrawal on each of the endogenous opioid peptides and receptors in rodent models. In addition, we review the studies that utilized opioid peptide or receptor knockout mice in order to identify and/or clarify the role of different components of the opioid system in cocaine-addictive behaviours and in cocaine-induced alterations of brain neurochemistry. The review of these studies indicates a region-specific activation of the µ-opioid receptor system following chronic cocaine exposure, which may contribute towards the rewarding effect of the drug and possibly towards cocaine craving during withdrawal followed by relapse. Cocaine also causes a region-specific activation of the κ-opioid receptor/dynorphin system, which may antagonize the rewarding effect of the drug, and at the same time, contribute to the stress-inducing properties of the drug and the triggering of relapse. These conclusions have important implications for the development of effective pharmacotherapy for the treatment of cocaine addiction and the prevention of relapse.
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Affiliation(s)
- Ji Hoon Yoo
- Division of Biochemistry, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, UK
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17
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Mallory GW, Abulseoud O, Hwang SC, Gorman DA, Stead SM, Klassen BT, Sandroni P, Watson JC, Lee KH. The nucleus accumbens as a potential target for central poststroke pain. Mayo Clin Proc 2012; 87:1025-31. [PMID: 22980165 PMCID: PMC3498057 DOI: 10.1016/j.mayocp.2012.02.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Accepted: 02/09/2012] [Indexed: 12/21/2022]
Abstract
Although deep brain stimulation (DBS) has been found to be efficacious for some chronic pain syndromes, its usefulness in patients with central poststroke pain (CPSP) has been disappointing. The most common DBS targets for pain are the periventricular gray region (PVG) and the ventralis caudalis of the thalamus. Despite the limited success of DBS for CPSP, few alternative targets have been explored. The nucleus accumbens (NAC), a limbic structure within the ventral striatum that is involved in reward and pain processing, has emerged as an effective target for psychiatric disease. There is also evidence that it may be an effective target for pain. We describe a 72-year-old woman with a large right hemisphere infarct who subsequently experienced refractory left hemibody pain. She underwent placement of 3 electrodes in the right PVG, ventralis caudalis of the thalamus, and NAC. Individual stimulation of the NAC and PVG provided substantial improvement in pain rating. The patient underwent implantation of permanent electrodes in both targets, and combined stimulation has provided sustained pain relief at nearly 1 year after the procedure. These results suggest that the NAC may be an effective DBS target for CPSP.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Kendall H. Lee
- Department of Neurosurgery, Mayo Clinic, Rochester, MN
- Correspondence: Address to Kendall H. Lee, MD, PhD, Department of Neurosurgery, Mayo Clinic, 200 First St SW, Rochester, MN 55901
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18
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Saigusa T, Aono Y, Uchida T, Takada K, Verheij MM, Koshikawa N, Cools AR. The α1-, but not α2-, adrenoceptor in the nucleus accumbens plays an inhibitory role upon the accumbal noradrenaline and dopamine efflux of freely moving rats. Eur J Pharmacol 2012; 688:35-41. [DOI: 10.1016/j.ejphar.2012.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 04/24/2012] [Accepted: 05/07/2012] [Indexed: 02/06/2023]
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19
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Tanahashi S, Ueda Y, Nakajima A, Yamamura S, Nagase H, Okada M. Novel δ1-receptor agonist KNT-127 increases the release of dopamine and L-glutamate in the striatum, nucleus accumbens and median pre-frontal cortex. Neuropharmacology 2012; 62:2057-67. [PMID: 22266218 DOI: 10.1016/j.neuropharm.2012.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 01/02/2012] [Accepted: 01/09/2012] [Indexed: 11/29/2022]
Abstract
The effects of systemic δ1-agonist on neurotransmission remains obscure, since no selective δ1-agonist exists that can penetrate the blood-brain barrier. Recently, we succeeded in synthesizing a putative δ1-receptor agonist, KNT-127, which has been demonstrated the effectiveness of systemic administration against anxiety and depressive-like behavior. To clarify the functional selectivity of KNT-127 and neurotransmission regulating system of δ1-receptor, the present study investigated the interaction between KNT-127 and δ-receptor antagonists on the release of dopamine, L-glutamate and GABA in nucleus accumbens (NAc), striatum and median pre-frontal cortex (mPFC) using multi-probe microdialysis. Intraperitoneal administration of KNT-127 increased the release of dopamine and L-glutamate in three regions, but decreased and increased GABA releases in respective NAc and mPFC without affecting that in striatum. The effects of KNT-127 in the three regions were abrogated by δ1-antagonist but not by δ2-antagonist. MK801 inhibited KNT-127-induced dopamine release in striatum and NAc, but enhanced that in mPFC, inhibited KNT-127-induced mPFC GABA release without affecting KNT-127-induced GABA reduction in NAc. Muscimol enhanced KNT-127-induced dopamine release in mPFC. Sulpiride inhibited KNT-127-induced reduction of GABA release in NAc. The results indicated that KNT-127 is a selective δ1-agonist, and suggested that δ1-receptor directly activates the release of dopamine and L-glutamate in the striatum, NAc and mPFC, but not that of GABA in the three regions. δ1-receptor indirectly inhibited GABA release in NAc via activated dopaminergic transmission, while δ1-receptor indirectly enhanced GABA release in mPFC via activated glutamatergic transmission.
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Affiliation(s)
- Shunsuke Tanahashi
- Department of Psychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
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20
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Saigusa T, Aono Y, Sekino R, Uchida T, Takada K, Oi Y, Koshikawa N, Cools AR. In vivo neurochemical evidence that newly synthesised GABA activates GABA(B), but not GABA(A), receptors on dopaminergic nerve endings in the nucleus accumbens of freely moving rats. Neuropharmacology 2011; 62:907-13. [PMID: 21964521 DOI: 10.1016/j.neuropharm.2011.09.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 08/19/2011] [Accepted: 09/16/2011] [Indexed: 01/13/2023]
Abstract
GABA released from accumbal GABAergic interneurons plays an inhibitory role in the regulation of dopamine efflux through GABA(B) and GABA(A) receptors located on accumbal dopaminergic nerve endings. The cytosolic newly synthesised GABA alters vesicular GABA levels and, accordingly, the amount of GABA released from the neuron. Therefore, we hypothesised that glutamic acid decarboxylase (GAD) which generates GABA in accumbal GABAergic neurons, at least partly determines the GABA receptor subtype-mediated GABAergic tonus. To (in)validate this hypothesis, in vivo microdialysis was used to study the effects of an intra-accumbal infusion of the GAD inhibitor l-allylglycine (allylglycine) on the accumbal dopamine efflux of freely moving rats. The intra-accumbal infusion of allylglycine (50.0, 250.0 and 500.0 nmol) dose-dependently increased the accumbal dopamine levels. The co-administration of tetrodotoxin (720 pmol) suppressed the allylglycine (500.0 nmol)-induced dopamine efflux. The intra-accumbal infusion of GABA(B) receptor agonist baclofen (2.5 and 5.0 nmol) inhibited the allylglycine (500.0 nmol)-induced dopamine efflux. The baclofen's effects were counteracted by GABA(B) receptor antagonist saclofen (10.0 nmol). Neither GABA(A) receptor agonist (muscimol: 25.0 and 250.0 pmol) nor antagonist (bicuculline: 50.0 pmol) altered the allylglycine (250.0 and 500.0 nmol)-induced dopamine efflux. The present study provides in vivo neurochemical evidence that newly synthesised GABA that exerts an inhibitory tonus on the accumbal dopaminergic activity, acts at the level of GABA(B) receptors, but not GABA(A) receptors. The present study also shows that there is an allylglycine-insensitive GABA pool that release GABA exerting an inhibitory control of the accumbal dopaminergic activity, at the level of GABA(A) receptors. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
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Affiliation(s)
- Tadashi Saigusa
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
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21
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Sekino R, Saigusa T, Aono Y, Uchida T, Takada K, Oi Y, Koshikawa N, Cools AR. Dopamine D1-like receptors play only a minor role in the increase of striatal dopamine induced by striatally applied SKF38393. Eur J Pharmacol 2010; 648:80-6. [DOI: 10.1016/j.ejphar.2010.08.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 07/14/2010] [Accepted: 08/21/2010] [Indexed: 11/16/2022]
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22
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Shirayama Y, Chaki S. Neurochemistry of the nucleus accumbens and its relevance to depression and antidepressant action in rodents. Curr Neuropharmacol 2010; 4:277-91. [PMID: 18654637 DOI: 10.2174/157015906778520773] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 09/06/2005] [Accepted: 02/08/2006] [Indexed: 01/24/2023] Open
Abstract
There is accumulating evidence that the nucleus accumbens (NAc) plays an important role in the pathophysiology of depression. Given that clinical depression is marked by anhedonia (diminished interest or pleasure), dysfunction of the brain reward pathway has been suggested as contributing to the pathophysiology of depression.Since the NAc is the center of reward and learning, it is hypothesized that anhedonia might be produced by hampering the function of the NAc. Indeed, it has been reported that stress, drug exposure and drug withdrawal, all of which produce a depressive-phenotype, alter various functions within the NAc, leading to inhibited dopaminergic activity in the NAc.In this review, we describe various factors as possible candidates within the NAc for the initiation of depressive symptoms. First, we discuss the roles of several neurotransmitters and neuropeptides in the functioning of the NAc, including dopamine, glutamate, gamma-aminobutyric acid (GABA), acetylcholine, serotonin, dynorphin, enkephaline, brain-derived neurotrophic factor (BDNF), cAMP response element-binding protein (CREB), melanin-concentrating hormone (MCH) and cocaine- and amphetamine-regulated transcript (CART). Second, based on previous studies, we propose hypothetical relationships among these substances and the shell and core subregions of the NAc.
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Affiliation(s)
- Yukihiko Shirayama
- Department of Neuropsychiatry, Faculty of Medicine, Tottori University, Yonago, Japan.
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23
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Contribution of vesicular and cytosolic dopamine to the increased striatal dopamine efflux elicited by intrastriatal injection of SKF38393. Eur J Pharmacol 2009; 624:10-5. [DOI: 10.1016/j.ejphar.2009.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Revised: 09/18/2009] [Accepted: 10/08/2009] [Indexed: 11/24/2022]
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Yamamura S, Ohoyama K, Nagase H, Okada M. Zonisamide enhances delta receptor-associated neurotransmitter release in striato-pallidal pathway. Neuropharmacology 2009; 57:322-31. [PMID: 19482038 DOI: 10.1016/j.neuropharm.2009.05.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 05/17/2009] [Accepted: 05/19/2009] [Indexed: 11/26/2022]
Abstract
A recent randomized control study demonstrated that zonisamide (ZNS), an antiepileptic drug, is effective in Parkinson's disease at the lower than the therapeutic doses against epilepsy (25-50 mg/day); however, the detailed mechanism of antiparkinsonian effects of ZNS remains to be clarified. To determine the mechanism of antiparkinsonian effect of ZNS, we investigated the effects of ZNS on extracellular levels of dopamine in the striatum (STR), glutamate in substantia nigra pars reticulata (SNr), GABA in globus pallidus (GP), subthalamic nucleus (STN) and SNr, using multiple microdialysis probes. Striatal perfusion of 1000 microM ZNS (within therapeutic-relevant concentration against epilepsy) increased extracellular levels of dopamine in STR, whereas 100 microM ZNS (lower than the therapeutic-relevant concentration against epilepsy but within the therapeutic rage against Parkinson's disease) did not affect it. Striatal perfusion of ZNS (100 and 1000 microM) decreased the extracellular levels of GABA in STN and glutamate in SNr, but decreased extracellular GABA level in GP without affecting GABA level in SNr. These concentration-dependent effects of ZNS on extracellular neurotransmitter levels were independent of dopamine and delta(2) receptors; however, blockade of delta(1) receptor inhibited the effects of ZNS. Furthermore, activation of delta(1) receptor enhanced the effects of ZNS on neurotransmitter level. These results suggest that ZNS does not affect the direct pathway but inhibits the indirect pathway, which is mediated by delta(1) receptor. Therefore, the antiparkinsonian effects of ZNS seem to be mediated through the interaction between lower than therapeutically-relevant concentration against epilepsy of ZNS (100 microM) and delta(1) receptor.
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Affiliation(s)
- S Yamamura
- Department of Psychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
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25
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Mizoguchi N, Saigusa T, Aono Y, Sekino R, Takada K, Oi Y, Ueda K, Koshikawa N, Cools AR. The reboxetine-induced increase of accumbal dopamine efflux is inhibited by l-propranolol: a microdialysis study with freely moving rats. Eur J Pharmacol 2008; 601:94-8. [PMID: 18996113 DOI: 10.1016/j.ejphar.2008.10.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 10/06/2008] [Accepted: 10/23/2008] [Indexed: 10/21/2022]
Abstract
In vivo microdialysis was used to study the effects of the locally applied selective noradrenaline uptake inhibitor reboxetine on the baseline noradrenaline and dopamine efflux in the nucleus accumbens of freely moving rats. The effects of intra-accumbal infusion of the beta-adrenoceptor antagonist l-propranolol on the reboxetine-elicited noradrenaline and dopamine efflux in the nucleus accumbens were also analysed. The intra-accumbal infusion of reboxetine (1.2 and 12 pmol) significantly increased both the accumbal noradrenaline efflux and the accumbal dopamine efflux. The intra-accumbal infusion of the chosen doses of l-propranolol (300 and 1200 pmol) did not alter the accumbal noradrenaline and dopamine efflux. The l-propranolol treatment did not affect the reboxetine-elicited accumbal noradrenaline efflux, but it significantly inhibited the reboxetine-elicited increase of accumbal dopamine efflux. The doses mentioned are the total amount of drug over the infusion period that varied across the drugs (60 or 120 min). The present study shows that the intra-accumbal infusion of selective noradrenaline uptake inhibitor reboxetine increases noradrenaline as well as dopamine efflux in the nucleus accumbens of freely moving rats. This study also indicates that inhibition of accumbal beta-adrenoceptors prevented the increase of the reboxetine-induced accumbal dopamine efflux. It is suggested that the reboxetine-induced increase of the endogenous accumbal noradrenaline activates among others accumbal beta-adrenoceptors that, in turn, stimulate the accumbal release of dopamine.
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Affiliation(s)
- Naoko Mizoguchi
- Department of Dysphagia Rehabilitation, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
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In vivo neurochemical effects of the NR2B selective NMDA receptor antagonist CR 3394 in 6-hydroxydopamine lesioned rats. Eur J Pharmacol 2008; 584:297-305. [DOI: 10.1016/j.ejphar.2008.02.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 02/01/2008] [Accepted: 02/13/2008] [Indexed: 11/21/2022]
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Camarini R, Griffin WC, Yanke AB, Rosalina dos Santos B, Olive MF. Effects of adolescent exposure to cocaine on locomotor activity and extracellular dopamine and glutamate levels in nucleus accumbens of DBA/2J mice. Brain Res 2008; 1193:34-42. [PMID: 18178178 PMCID: PMC2288750 DOI: 10.1016/j.brainres.2007.11.045] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 11/21/2007] [Accepted: 11/28/2007] [Indexed: 11/23/2022]
Abstract
Adolescents differ from adults in their acute sensitivity to several drugs of abuse, but little is known about the long-term neurobehavioral effects of adolescent drug exposure. To explore this further, we evaluated the locomotor responses to repeated cocaine administration in adolescent and adult male DBA/2J mice and alterations in extracellular levels of dopamine (DA) and glutamate (GLU) in the nucleus accumbens (NAc) in response to a subsequent cocaine challenge. Adolescent and adult mice were treated daily with saline or cocaine (10 mg/kg, i.p) for 9 consecutive days. Ten days following the last injection, animals were implanted with microdialysis probes and 24 h later microdialysis samples were collected before and after an acute cocaine challenge. Adolescents but not adults demonstrated development of behavioral sensitization to cocaine. Microdialysis procedures revealed that cocaine-treated mice displayed greater peak increases in extracellular DA in response to a subsequent cocaine challenge as compared to saline-treated mice, in contrast with lower peak increases in extracellular GLU. While adults exhibited greater peaks in extracellular DA in response to cocaine than adolescents did, adolescent mice presented a more rapid onset of peak extracellular DA levels than adults. Our results indicate differences in the behavioral and neurochemical responses to cocaine in adolescent versus adult mice, which may be relevant to the increased risk of developing addiction in humans who are exposed to drugs of abuse during adolescence.
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Affiliation(s)
- Rosana Camarini
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
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Saigusa T, Aono Y, Mizoguchi N, Iwakami T, Takada K, Oi Y, Ueda K, Koshikawa N, Cools AR. Role of GABA B receptors in the endomorphin-1-, but not endomorphin-2-, induced dopamine efflux in the nucleus accumbens of freely moving rats. Eur J Pharmacol 2007; 581:276-82. [PMID: 18206140 DOI: 10.1016/j.ejphar.2007.12.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 11/27/2007] [Accepted: 12/11/2007] [Indexed: 11/28/2022]
Abstract
In vivo microdialysis was used to study the effects of the locally applied GABA B receptor antagonist 2-hydroxysaclofen and GABA B receptor agonist baclofen on the basal dopamine efflux as well as on the endomorphin-1- and endomorphin-2-induced dopamine efflux in the nucleus accumbens of freely moving rats. 2-Hydroxysaclofen (100 and 500 nmol) increased basal dopamine efflux. Baclofen (2.5 and 5 nmol) failed to affect basal dopamine efflux. 2-Hydroxysaclofen (1 and 10 nmol) which did not alter the basal dopamine efflux, enhanced the endomorphin-1 (25 nmol)-induced dopamine efflux. Baclofen (2.5 and 5 nmol) failed to affect endomorphin-1 (25 nmol)-induced dopamine efflux, but it counteracted the 2-hydroxysaclofen-induced increase of the endomorphin-1-elicited dopamine efflux. Neither 2-hydroxysaclofen (10 nmol) nor baclofen (5 nmol) affected the endomorphin-2 (25 nmol)-induced dopamine efflux. The doses mentioned are the total amount of drug over the infusion period that varied across the drugs (25 or 50 min). These results suggest that accumbal GABA B receptor plays an inhibitory role on the basal as well as the endomorphin-1-elicited accumbal dopamine efflux. The present results support our earlier reported notion that endomorphin-1 and endomorphin-2 increase accumbal dopamine efflux by different mechanisms. Finally, it is suggested that a decrease of endogenous accumbal GABA reduces the accumbal GABA B receptor-mediated GABA-ergic inhibition, enhancing thereby the accumbal dopamine efflux.
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Affiliation(s)
- Tadashi Saigusa
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
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29
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Jutkiewicz EM, Baladi MG, Folk JE, Rice KC, Woods JH. The delta-opioid receptor agonist SNC80 [(+)-4-[alpha(R)-alpha-[(2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl]-(3-methoxybenzyl)-N,N-diethylbenzamide] synergistically enhances the locomotor-activating effects of some psychomotor stimulants, but not direct dopamine agonists, in rats. J Pharmacol Exp Ther 2007; 324:714-24. [PMID: 17986650 DOI: 10.1124/jpet.107.123844] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The nonpeptidic delta-opioid agonist SNC80 [(+)-4-[alpha(R)-alpha-[(2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl]-(3-methoxybenzyl)-N,N-diethylbenzamide] produces many stimulant-like behavioral effects in rodents and monkeys, such as locomotor stimulation, generalization to cocaine in discrimination procedures, and antiparkinsonian effects. Tolerance to the locomotor-stimulating effects of SNC80 develops after a single administration of SNC80 in rats; it is not known whether cross-tolerance develops to the effects of other stimulant compounds. In the initial studies to determine whether SNC80 produced cross-tolerance to other stimulant compounds, it was discovered that amphetamine-stimulated locomotor activity was greatly enhanced in SNC80-pretreated rats. This study evaluated acute cross-tolerance between delta-opioid agonists and other locomotor-stimulating drugs. Locomotor activity was measured in male Sprague-Dawley rats implanted with radiotransmitters, and activity levels were recorded in the home cage environment. Three-hour SNC80 pretreatment produced tolerance to further delta-opioid receptor stimulation but also augmented greatly amphetamine-stimulated locomotor activity in a dose-dependent manner. Pretreatments with other delta-opioid agonists, (+)BW373U86 [(+)-4-[alpha(R)-alpha-[(2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl]-3-hydroxybenzyl]-N,N-diethylbenzamide] and oxymorphindole (17-methyl-6,7-dehydro-4,5-epoxy-3,14-dihydroxy-6,7,2',3'-indolomorphinan), also modified amphetamine-induced activity levels. SNC80 pretreatment enhanced the stimulatory effects of the dopamine/norepinephrine transporter ligands cocaine and nomifensine (1,2,3,4-tetrahydro-2-methyl-4-phenyl-8-isoquinolinanmine maleate salt), but not the direct dopamine receptor agonists SKF81297 [R-(+)-6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide] and quinpirole [trans-(-)-(4alphaR)-4,4a, 5,6,7,8,8a,9-octahydro-5-propyl-1H-pyrazolo[3,4-g] quinoline monohydrochloride]. In conclusion, SNC80 enhanced the locomotor-stimulating effects of monoamine transporter ligands suggesting that delta-opioid receptor activation might alter the functional activity of monoamine transporters or presynaptic monoamine terminals.
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Affiliation(s)
- Emily M Jutkiewicz
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Science Research Building III, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-0632, USA.
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30
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Aono Y, Saigusa T, Mizoguchi N, Iwakami T, Takada K, Gionhaku N, Oi Y, Ueda K, Koshikawa N, Cools AR. Role of GABAA receptors in the endomorphin-1-, but not endomorphin-2-, induced dopamine efflux in the nucleus accumbens of freely moving rats. Eur J Pharmacol 2007; 580:87-94. [PMID: 18021767 DOI: 10.1016/j.ejphar.2007.10.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2007] [Revised: 10/10/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
Abstract
In vivo microdialysis was used to study the effects of the locally applied GABA(A) receptor agonist muscimol and GABA(A) receptor antagonist bicuculline on the basal dopamine efflux as well as on the endomorphin-1- and endomorphin-2-induced dopamine efflux in the nucleus accumbens of freely moving rats. Muscimol (2500 pmol) and bicuculline (5 and 10 nmol) increased basal dopamine efflux. Bicuculline (50 pmol) inhibited the muscimol (2500 pmol)-induced dopamine efflux. Muscimol (250 pmol), but not bicuculline (50 and 500 pmol), enhanced the endomorphin-1 (25 nmol)-induced dopamine efflux. Bicuculline (50 pmol) counteracted the muscimol (250 pmol)-induced increase of the endomorphin-1-elicited dopamine efflux. Neither muscimol (25 and 250 pmol) nor bicuculline (50 and 500 pmol) affected the endomorphin-2 (25 nmol)-induced dopamine efflux. The doses mentioned are the total amount of drug over the infusion period (25 or 50 min) that varied across the drugs. The finding that muscimol and bicuculline increased basal dopamine efflux may imply that these drugs acted at different sites. It is suggested that (1) muscimol acts at GABA(A) receptors on GABA-ergic neurons that exert an inhibitory control of dopaminergic neurons and, accordingly, disinhibits these dopaminergic neurons, and that (2) bicuculline acts directly at GABA(A) receptors on dopaminergic neurons and, accordingly, removes the inhibitory control of these dopaminergic neurons. The finding that an agonist, but not antagonist, of GABA(A) receptors enhanced the endomorphin-1's effects might indicate that endomorphin-1 produced a floor effect at the level of GABA(A) receptors located on presynaptic, dopaminergic terminals. Finally, the present results support our earlier reported notion that endomorphin-1 and endomorphin-2 increase accumbal dopamine efflux by different mechanisms.
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Affiliation(s)
- Yuri Aono
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Tokyo 101-8310, Japan
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31
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Fulford AJ, Marsden CA. An intact dopaminergic system is required for context-conditioned release of 5-HT in the nucleus accumbens of postweaning isolation-reared rats. Neuroscience 2007; 149:392-400. [PMID: 17869434 DOI: 10.1016/j.neuroscience.2007.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 07/27/2007] [Accepted: 08/02/2007] [Indexed: 10/23/2022]
Abstract
We investigated the effect of the tyrosine hydroxylase inhibitor, alpha-methyl-para-tyrosine (AMPT) on extracellular dopamine and 5-HT levels in the nucleus accumbens of group- and isolation-reared rats. Microdialysis with high-performance liquid chromatography-electrochemical detection was used to quantify dopamine and 5-HT efflux in the nucleus accumbens following foot shock and in association with a conditioned emotional response (CER). Isolation- and group-reared rats received i.p. injections of either saline (0.9%) or AMPT (200 mg/kg) 15 h and 2 h prior to sampling. There was no significant difference between saline-treated isolation- or group-reared rats for basal efflux of dopamine or 5-HT, however as expected, AMPT-treatment significantly reduced dopamine efflux in both groups to an equivalent level (50-55% saline-treated controls). Exposure to mild foot shock stimulated basal dopamine efflux in saline-treated groups only, although the effect was significantly greater in isolation-reared rats. In AMPT-treated rats, foot shock did not affect basal dopamine efflux in either rearing group. Foot shock evoked a prolonged increase in 5-HT efflux in both isolation- and group-reared saline-treated rats but had no effect on 5-HT efflux in AMPT-treated rats. In response to CER, isolation-rearing was associated with significantly greater efflux of both dopamine and 5-HT in saline-treated rats, compared to saline-treated, group-reared controls. However in AMPT-treated rats, efflux of dopamine or 5-HT did not change in response to CER. These data suggest that unconditioned or conditioned stress-induced changes in 5-HT release of the nucleus accumbens are dependent upon intact catecholaminergic neurotransmission. Furthermore, as the contribution of noradrenaline to catecholamine efflux in the nucleus accumbens is relatively minor compared to dopamine, our findings suggest that dopamine efflux in the nucleus accumbens is important for the local regulation of 5-HT release in this region. Finally, these findings implicate the isolation-enhanced presynaptic dopamine function in the accumbens with the augmented ventral striatal 5-HT neurotransmission characterized by isolation-reared rats.
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Affiliation(s)
- A J Fulford
- Department of Anatomy, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK.
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Aono Y, Saigusa T, Watanabe S, Iwakami T, Mizoguchi N, Ikeda H, Ishige K, Tomiyama K, Oi Y, Ueda K, Rausch WD, Waddington JL, Ito Y, Koshikawa N, Cools AR. Role of alpha adrenoceptors in the nucleus accumbens in the control of accumbal noradrenaline efflux: a microdialysis study with freely moving rats. J Neural Transm (Vienna) 2007; 114:1135-42. [PMID: 17533511 DOI: 10.1007/s00702-007-0745-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 04/12/2007] [Indexed: 11/25/2022]
Abstract
Microdialysis technique was used to study the effects of the locally applied alpha adrenoceptor agonist phenylephrine and antagonist phentolamine on the basal noradrenaline efflux as well as on the noradrenaline uptake inhibitor desipramine-elicited noradrenaline efflux in the nucleus accumbens (NAc) of freely moving rats. Tetrodotoxin reduced basal noradrenaline efflux by 72%, whereas desipramine increased it by 204%. Phenylephrine reduced the basal noradrenaline efflux by 32% and phentolamine blocked this effect. Phentolamine elevated the basal noradrenaline efflux by 150% and phenylephrine counteracted this effect. The desipramine-elicited noradrenaline efflux was not affected by phenylephrine, but enhanced by phentolamine. Desipramine counteracted the effects of phenylephrine and potentiated those of phentolamine. These results indicate that the accumbal noradrenaline efflux is under inhibitory control of alpha adrenoceptors that are suggested to be presynaptically located on adrenergic nerve terminals in the NAc. Furthermore, this study suggests that the conformational state of alpha adrenoceptors varies across the available amount of noradrenaline. The clinical impact of these data is discussed.
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Affiliation(s)
- Y Aono
- Department of Pharmacology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
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Abstract
This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 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 (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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Joo JD, Kim M, D'Agati VD, Lee HT. Ischemic preconditioning provides both acute and delayed protection against renal ischemia and reperfusion injury in mice. J Am Soc Nephrol 2006; 17:3115-23. [PMID: 16988058 DOI: 10.1681/asn.2006050424] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Acute as well as delayed ischemic preconditioning (IPC) provides protection against cardiac and neuronal ischemia reperfusion (IR) injury. This study determined whether delayed preconditioning occurs in the kidney and further elucidated the mechanisms of renal IPC in mice. Mice were subjected to IPC (four cycles of 5 min of ischemia and reperfusion) and then to 30 min of renal ischemia either 15 min (acute IPC) or 24 h (delayed IPC) later. Both acute and delayed renal IPC provided powerful protection against renal IR injury. Inhibition of Akt but not extracellular signal-regulated kinase phosphorylation prevented the protection that was afforded by acute IPC. Neither extracellular signal-regulated kinase nor Akt inhibition prevented protection that was afforded by delayed renal IPC. Pretreatment with an antioxidant, N-(2-mercaptopropionyl)-glycine, to scavenge free radicals prevented the protection that was provided by acute but not delayed renal IPC. Inhibition of protein kinase C or pertussis toxin-sensitive G-proteins attenuated protection from both acute and delayed renal IPC. Delayed renal IPC increased inducible nitric oxide synthase (iNOS) as well as heat-shock protein 27 synthesis, and the renal protective effects of delayed preconditioning were attenuated by a selective inhibitor of iNOS (l-N(6)[1-iminoethyl]lysine). Moreover, delayed IPC was not observed in iNOS knockout mice. Both acute and delayed IPC were independent of A(1) adenosine receptors (AR) as a selective A(1)AR antagonist failed to block preconditioning and acute and delayed preconditioning occurred in mice that lacked A(1)AR. Therefore, this study demonstrated that acute or delayed IPC provides renal protection against IR injury in mice but involves distinct signaling pathways.
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Affiliation(s)
- Jin Deok Joo
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032-3784, USA
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Okutsu H, Watanabe S, Takahashi I, Aono Y, Saigusa T, Koshikawa N, Cools AR. Endomorphin-2 and endomorphin-1 promote the extracellular amount of accumbal dopamine via nonopioid and mu-opioid receptors, respectively. Neuropsychopharmacology 2006; 31:375-83. [PMID: 16034447 DOI: 10.1038/sj.npp.1300804] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Activation of mu-opioid receptors in the nucleus accumbens (NAc) is known to increase accumbal dopamine efflux in rats. Endomorphin-2 (Tyr-Pro-Phe-Phe-NH(2); EM-2) and endomorphin-1 (Tyr-Pro-Trp-Phe-NH(2); EM-1) are suggested to be the endogenous ligands for the mu-opioid receptor. As the ability of EM-2 and EM-1 to alter the accumbal extracellular dopamine level has not yet been studied in freely moving rats, the present study was performed, using a microdialysis technique that allows on-line monitoring of the extracellular dopamine with a temporal resolution of 5 min. A 25 min infusion of either EM-2 or EM-1 into the NAc (5, 25, and 50 nmol) produced a dose-dependent increase of the accumbal dopamine level. The EM-2 (50 nmol)- and EM-1 (25 and 50 nmol)-induced dopamine efflux were abolished by intra-accumbal perfusion of tetrodotoxin (2 muM). Intra-accumbal perfusion of the mu-opioid receptor antagonist CTOP (D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Phe-Thr-NH(2); 3 nmol) failed to affect the EM-2 (50 nmol)-induced dopamine release, whereas it significantly inhibited the EM-1 (25 and 50 nmol)-induced dopamine release. The EM-1 (50 nmol)-induced accumbal dopamine efflux was significantly reduced by the systemic administration of the putative mu1-opioid receptor antagonist naloxonazine (15 mg/kg, intraperitoneally (i.p.), given 24 h before starting the perfusion). Systemic administration of the aspecific opioid receptor antagonist naloxone (1 mg/kg, i.p., given 10 or 20 min before starting the perfusion) also failed to affect the EM-2 (50 nmol)-induced dopamine efflux, whereas it significantly inhibited the EM-1 (25 and 50 nmol)-induced dopamine efflux. The present study shows that the intra-accumbal infusion of EM-2 and EM-1 increases accumbal dopamine efflux by mechanisms that fully differ. It is concluded that the effects of EM-2 are not mediated via opioid receptors in contrast to the effects of EM-1 that are mediated via mu1-opioid receptors in the NAc.
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Affiliation(s)
- Hiroko Okutsu
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda-shi, Chiba, Japan
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Watanabe S, Fusa K, Takada K, Aono Y, Saigusa T, Koshikawa N, Cools AR. Effects of alpha-methyl-p-tyrosine on extracellular dopamine levels in the nucleus accumbens and the dorsal striatum of freely moving rats. J Oral Sci 2005; 47:185-90. [PMID: 16415562 DOI: 10.2334/josnusd.47.185] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Alpha-methyl-p-tyrosine (AMPT) is known to inhibit the formation of dopamine (DA) in the cytosol of dopaminergic neurons and is therefore used to study the role of the cytosolic DA pools. AMPT is usually administered systemically. In the present study, however, the effects of locally infused AMPT on the efflux of DA from the nucleus accumbens and dorsal striatum were analyzed, using in vivo brain microdialysis in unanesthetized rats. The administration of AMPT (100 microM, 4 h) into the nucleus accumbens reduced accumbal DA output to 30% of its baseline level. When it was infused into the dorsal striatum, however, it reduced striatal DA output to 60% of its baseline level. At first sight, these data suggest that the amount of DA available from the AMPT-sensitive pool is larger in the nucleus accumbens than in the striatum. However, this cannot be the case, as the decrease in accumbal and striatal DA efflux induced by systemic administration of AMPT (250 mg/kg given intra-peritoneally) was identical. These results show that local infusion of AMPT is a valuable tool for analyzing the role of AMPT-sensitive pools within a particular brain area, but it cannot be used to compare effects across different brain structures because a fixed dose of AMPT differentially affected the nucleus accumbens and the dorsal striatum.
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Affiliation(s)
- Shu Watanabe
- Department of Pharmacology, Nihon University School of Dentistry, Tokyo, Japan
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Watanabe S, Aono Y, Fusa K, Takada K, Saigusa T, Koshikawa N, Cools AR. Contribution of vesicular and cytosolic dopamine to the increased striatal dopamine efflux elicited by intrastriatal injection of dexamphetamine. Neuroscience 2005; 136:251-7. [PMID: 16181742 DOI: 10.1016/j.neuroscience.2005.07.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 06/04/2005] [Accepted: 07/25/2005] [Indexed: 11/27/2022]
Abstract
Systemic administration of high doses of dexamphetamine induces a dopamine efflux that has its intracellular origin in both the vesicular, reserpine-sensitive dopamine pool and the cytosolic, alpha-methyl-para-tyrosine-sensitive, newly synthesized dopamine pool. It remains unknown whether locally administered dexamphetamine produces similar effects. Using a brain microdialysis technique that is combined with a microinjection needle, the contribution of the vesicular and cytosolic pools to the dopamine efflux induced by striatal injection of dexamphetamine was analyzed in rats. The transient striatal dopamine efflux induced by intrastriatal injection of dexamphetamine (1.0 microg/0.5 microl) was significantly reduced by systemic administration of reserpine (5mg/kg i.p., given 24 h earlier) or alpha-methyl-para-tyrosine (250 mg/kg i.p., given 2 h earlier). The effects of dexamphetamine on the striatal dopamine were nearly nullified by combined treatment with reserpine and alpha-methyl-para-tyrosine. The sum of the amounts of extracellular dopamine that was sensitive to either reserpine or alpha-methyl-para-tyrosine, was far greater than 100%, namely 146.1% of the basal dopamine level and 144.0% of the dexamphetamine-induced dopamine level. The present study indicates that both the vesicular dopamine pool and the cytosolic dopamine pool contribute to the transient increase of striatal dopamine efflux induced by intrastriatal injection of dexamphetamine. This study also suggests that striatally applied dexamphetamine can promote the redistribution of rat striatal dopamine from vesicles to the cytosol in vivo.
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Affiliation(s)
- S Watanabe
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
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