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Pirino BE, Hawks A, Carpenter BA, Candelas PG, Gargiulo AT, Curtis GR, Karkhanis AN, Barson JR. Kappa-opioid receptor stimulation in the nucleus accumbens shell and ethanol drinking: Differential effects by rostro-caudal location and level of drinking. Neuropsychopharmacology 2024; 49:1550-1558. [PMID: 38528134 PMCID: PMC11319348 DOI: 10.1038/s41386-024-01850-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 03/27/2024]
Abstract
Although the kappa-opioid receptor (KOR) and its endogenous ligand, dynorphin, are believed to be involved in ethanol drinking, evidence on the direction of their effects has been mixed. The nucleus accumbens (NAc) shell densely expresses KORs, but previous studies have not found KOR activation to influence ethanol drinking. Using microinjections into the NAc shell of male and female Long-Evans rats that drank under the intermittent-access procedure, we found that the KOR agonist, U50,488, had no effect on ethanol drinking when injected into the middle NAc shell, but that it promoted intake in males and high-drinking females in the caudal NAc shell and high-drinking females in the rostral shell, and decreased intake in males and low-drinking females in the rostral shell. Conversely, injection of the KOR antagonist, nor-binaltorphimine, stimulated ethanol drinking in low-drinking females when injected into the rostral NAc shell and decreased drinking in high-drinking females when injected into the caudal NAc shell. These effects of KOR activity were substance-specific, as U50,488 did not affect sucrose intake. Using quantitative real-time PCR, we found that baseline gene expression of the KOR was higher in the rostral compared to caudal NAc shell, but that this was upregulated in the rostral shell with a history of ethanol drinking. Our findings have important clinical implications, demonstrating that KOR stimulation in the NAc shell can affect ethanol drinking, but that this depends on NAc subregion, subject sex, and ethanol intake level, and suggesting that this may be due to differences in KOR expression.
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Affiliation(s)
- Breanne E Pirino
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Annie Hawks
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Brody A Carpenter
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Pelagia G Candelas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Andrew T Gargiulo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Genevieve R Curtis
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Anushree N Karkhanis
- Department of Psychology, Binghamton University - SUNY, Binghamton, NY, 13902, USA
| | - Jessica R Barson
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA.
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Karkhanis AN, West AM, Jones SR. Kappa opioid receptor agonist U50,488 inhibits dopamine more in caudal than rostral nucleus accumbens core. Basic Clin Pharmacol Toxicol 2023; 133:526-534. [PMID: 37539456 DOI: 10.1111/bcpt.13929] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 06/07/2023] [Accepted: 07/14/2023] [Indexed: 08/05/2023]
Abstract
The nucleus accumbens (NAc) core is involved in regulating stress and shaping reward seeking behaviours. Multiple neuromodulators, including dynorphin/kappa opioid receptor (KOR) and dopamine systems, converge in this area to influence behavioural outcomes. KOR activation acutely inhibits dopamine release and chronically depresses overall dopamine transmission. Recently, studies in the NAc shell have revealed that the impact of KOR activation on behaviour is regionally specific, and these rostro-caudal differences are likely driven by greater control of KORs over dopamine inhibition in the caudal compared with rostral subregion. Given the importance of NAc core, particularly the interaction between KORs and dopamine in regulating reward seeking behaviours, we examined the impact of KOR activation on dopamine release and uptake along the rostro-caudal axis in the NAc core of male and female mice. Using ex vivo fast scan cyclic voltammetry, we observed that KOR mediated inhibition of dopamine release was significantly greater in caudal compared with rostral NAc core with no significant sex differences observed. These data suggest that KORs regulate dopamine release differentially along the rostro-caudal axis, providing a new axis on which to examine the process by which the KOR/dopamine system controls reward encoding.
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Affiliation(s)
| | - Alyssa M West
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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Pirino BE, Kelley AM, Karkhanis AN, Barson JR. A critical review of effects on ethanol intake of the dynorphin/kappa opioid receptor system in the extended amygdala: From inhibition to stimulation. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2023; 47:1027-1038. [PMID: 37042026 PMCID: PMC10289127 DOI: 10.1111/acer.15078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 04/03/2023] [Accepted: 04/06/2023] [Indexed: 04/13/2023]
Abstract
The dynorphin (DYN)/kappa opioid receptor (KOR) system has increasingly been investigated as a possible pharmacotherapeutic target for alcohol use disorder, but findings on the direction of its effects have been mixed. Activation of KORs by DYN has been shown to elicit dysphoric effects, and the DYN/KOR system has canonically been considered particularly important in driving alcohol intake through negative reinforcement in dependent states. However, this review also highlights its activity in opposing the positive reinforcement that drives alcohol intake at earlier stages. Both DYN and KORs are concentrated in the extended amygdala, a set of interconnected regions that includes the bed nucleus of the stria terminalis, central nucleus of the amygdala, and nucleus accumbens shell. This review focuses on the role of the DYN/KOR system in the extended amygdala in ethanol use. It begins by examining the effects of ethanol on the expression of DYN/KOR in the extended amygdala, expression of DYN/KOR in alcohol-preferring and alcohol-avoiding animals, and the effects of knocking out DYN/KOR genes on ethanol intake. Then, it examines the effects on ethanol use in both dependent and nondependent states from systemic pharmacological manipulations of DYN/KOR and from specific manipulation of this system in regions of the extended amygdala. We propose that greater expression and binding of DYN/KOR, by reducing the positive reinforcement that drives early stages of intake, initially acts to prevent the escalation of ethanol drinking. However, prolonged, binge-like, or intermittent ethanol intake enhances levels of DYN/KOR in the extended amygdala such that the system ultimately facilitates the negative reinforcement that drives later stages of ethanol drinking. This review highlights the potential of the DYN/KOR system as a target that can affect different outcomes across different stages of ethanol drinking and the development of alcohol use disorder.
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Affiliation(s)
- Breanne E. Pirino
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, P.A. 19129
| | - Abigail M. Kelley
- Department of Psychology, Binghamton University – SUNY, Binghamton, N.Y. 13902
| | | | - Jessica R. Barson
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, P.A. 19129
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Kappa Opioid Receptor Mediated Differential Regulation of Serotonin and Dopamine Transporters in Mood and Substance Use Disorder. Handb Exp Pharmacol 2021; 271:97-112. [PMID: 34136961 DOI: 10.1007/164_2021_499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Dynorphin (DYN) is an endogenous neurosecretory peptide which exerts its activity by binding to the family of G protein-coupled receptors, namely the kappa opioid receptor (KOR). Opioids are associated with pain, analgesia, and drug abuse, which play a central role in mood disorders with monoamine neurotransmitter interactions. Growing evidence demonstrates the cellular signaling cascades linked to KOR-mediated monoamine transporters regulation in cell models and native brain tissues. This chapter will review DYN/KOR role in mood and addiction in relevance to dopaminergic and serotonergic neurotransmissions. Also, we discuss the recent findings on KOR-mediated differential regulation of serotonin and dopamine transporters (SERT and DAT). These findings led to a better understanding of the role of DYN/KOR system in aminergic neurotransmission via its modulatory effect on both amine release and clearance. Detailed knowledge of these processes at the molecular level enables designing novel pharmacological reagents to target transporter motifs to treat mood and addiction and reduce unwanted side effects such as aversion, dysphoria, sedation, and psychomimesis.
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Kappa-opioid receptor-dependent changes in dopamine and anxiety-like or approach-avoidance behavior occur differentially across the nucleus accumbens shell rostro-caudal axis. Neuropharmacology 2020; 181:108341. [PMID: 33011200 DOI: 10.1016/j.neuropharm.2020.108341] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 01/24/2023]
Abstract
Neural circuit engagement within the nucleus accumbens (NAc) shell is implicated in the regulation of both negative and positive affect. Classically, the dynorphin/kappa opioid receptor (KOR) system in the NAc was believed to promote aversion, while dopamine was viewed as interacting with reward behavior, and KOR activation was known to inhibit dopamine release. Recently, however, both the KOR and dopamine systems have, separately, been shown to have differential effects across the rostro-caudal axis of the NAc shell on hedonic responses. Whether or not this is due to interactions between KORs and dopamine, and if it extends to anxiety-like or approach-avoidance behaviors, remains to be determined. In this study, we examined in rats the relationship between the KOR and dopamine systems in both the rostral and caudal NAc shell using ex vivo fast scan cyclic voltammetry and the impact of KOR activation on affective behavior using exploration-based tasks. We report here that activation of KORs in the caudal NAc shell significantly inhibits dopamine release, stimulates rearing behavior in a novel environment, increases anxiety-like or avoidance behavior, and reduces locomotor activity. In contrast, activation of KORs in the rostral NAc shell inhibits dopamine release to a lesser extent and instead reduces anxiety-like behavior or increases approach behavior. Taken together, these results indicate that there is heterogeneity across the rostro-caudal axis of the NAc shell in the effects of KOR stimulation on affective behaviors, and they suggest that this might be due to differences in KOR control over dopamine release.
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Karkhanis AN, Al-Hasani R. Dynorphin and its role in alcohol use disorder. Brain Res 2020; 1735:146742. [PMID: 32114059 DOI: 10.1016/j.brainres.2020.146742] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/04/2020] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
Abstract
The dynorphin / kappa opioid receptor (KOR) system has been implicated in many aspects that influence neuropsychiatric disorders. Namely, this system modulates neural circuits that primarily regulate reward seeking, motivation processing, stress responsivity, and pain sensitivity, thus affecting the development of substance and alcohol use disorder (AUD). The effects of this system are often bidirectional and depend on projection targets. To date, a majority of the studies focusing on this system have examined the KOR function using agonists and antagonists. Indeed, there are studies that have examined prodynorphin and dynorphin levels by measuring mRNA and tissue content levels; however, static levels of the neuropeptide and its precursor do not explain complete and online function of the peptide as would be explained by measuring dynorphin transmission in real time. New and exciting methods using optogenetics, chemogenetics, genetic sensors, fast scan cyclic voltammetry are now being developed to detect various neuropeptides with a focus on opioid peptides, including dynorphin. In this review we discuss studies that examine dynorphin projections in areas involved in AUD, its functional involvement in AUD and vulnerability to develop AUD at various ages. Moreover, we discuss dynorphin's role in promoting AUD by dysregulation motivation circuits and how advancements in opioid peptide detection will further our understanding.
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Affiliation(s)
- Anushree N Karkhanis
- Department of Psychology, Developmental Exposure Alcohol Research Center, Center for Developmental and Behavioral Neuroscience, Binghamton University - SUNY, 4400 Vestal Parkway East, Binghamton, NY 13902, USA.
| | - Ream Al-Hasani
- Department of Pharmaceutical and Administrative Sciences, St. Louis College of Pharmacy, Department of Anesthesiology Washington University in St. Louis, Center for Clinical Pharmacology, Washington University School of Medicine & St. Louis College of Pharmacy 660 S.Euclid, Box 8054, St. Louis, MO 63110, USA.
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Burtscher J, Schwarzer C. The Opioid System in Temporal Lobe Epilepsy: Functional Role and Therapeutic Potential. Front Mol Neurosci 2017; 10:245. [PMID: 28824375 PMCID: PMC5545604 DOI: 10.3389/fnmol.2017.00245] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/24/2017] [Indexed: 12/13/2022] Open
Abstract
Temporal lobe epilepsy is considered to be one of the most common and severe forms of focal epilepsies. Patients often develop cognitive deficits and emotional blunting along the progression of the disease. The high incidence of resistance to antiepileptic drugs and a frequent lack of admissibility to surgery poses an unmet medical challenge. In the urgent quest of novel treatment strategies, neuropeptides are interesting candidates, however, their therapeutic potential has not yet been exploited. This review focuses on the functional role of the endogenous opioid system with respect to temporal lobe epilepsy, specifically in the hippocampus. The role of dynorphins and kappa opioid receptors (KOPr) as modulators of neuronal excitability is well understood: both the reduced release of glutamate as well of postsynaptic hyperpolarization were shown in glutamatergic neurons. In line with this, low levels of dynorphin in humans and mice increase the risk of epilepsy development. The role of enkephalins is not understood so well. On one hand, some agonists of the delta opioid receptors (DOPr) display pro-convulsant properties probably through inhibition of GABAergic interneurons. On the other hand, enkephalins play a neuro-protective role under hypoxic or anoxic conditions, most probably through positive effects on mitochondrial function. Despite the supposed absence of endorphins in the hippocampus, exogenous activation of the mu opioid receptors (MOPr) induces pro-convulsant effects. Recently-expanded knowledge of the complex ways opioid receptors ligands elicit their effects (including biased agonism, mixed binding, and opioid receptor heteromers), opens up exciting new therapeutic potentials with regards to seizures and epilepsy. Potential adverse side effects of KOPr agonists may be minimized through functional selectivity. Preclinical data suggest a high potential of such compounds to control seizures, with a strong predictive validity toward human patients. The discovery of DOPr-agonists without proconvulsant potential stimulates the research on the therapeutic use of neuroprotective potential of the enkephalin/DOPr system.
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Affiliation(s)
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of InnsbruckInnsbruck, Austria
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Schank JR, Heilig M. Substance P and the Neurokinin-1 Receptor: The New CRF. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 136:151-175. [DOI: 10.1016/bs.irn.2017.06.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Al-Hasani R, McCall JG, Shin G, Gomez AM, Schmitz GP, Bernardi JM, Pyo CO, Park SI, Marcinkiewcz CM, Crowley NA, Krashes MJ, Lowell BB, Kash TL, Rogers JA, Bruchas MR. Distinct Subpopulations of Nucleus Accumbens Dynorphin Neurons Drive Aversion and Reward. Neuron 2015; 87:1063-77. [PMID: 26335648 DOI: 10.1016/j.neuron.2015.08.019] [Citation(s) in RCA: 252] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 07/07/2015] [Accepted: 08/08/2015] [Indexed: 12/20/2022]
Abstract
The nucleus accumbens (NAc) and the dynorphinergic system are widely implicated in motivated behaviors. Prior studies have shown that activation of the dynorphin-kappa opioid receptor (KOR) system leads to aversive, dysphoria-like behavior. However, the endogenous sources of dynorphin in these circuits remain unknown. We investigated whether dynorphinergic neuronal firing in the NAc is sufficient to induce aversive behaviors. We found that photostimulation of dynorphinergic cells in the ventral NAc shell elicits robust conditioned and real-time aversive behavior via KOR activation, and in contrast, photostimulation of dorsal NAc shell dynorphin cells induced a KOR-mediated place preference and was positively reinforcing. These results show previously unknown discrete subregions of dynorphin-containing cells in the NAc shell that selectively drive opposing behaviors. Understanding the discrete regional specificity by which NAc dynorphinerigic cells regulate preference and aversion provides insight into motivated behaviors that are dysregulated in stress, reward, and psychiatric disease.
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Affiliation(s)
- Ream Al-Hasani
- Departments of Anesthesiology, Division of Basic Research, Anatomy and Neurobiology, Division of Biomedical Engineering and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO 63110, USA.
| | - Jordan G McCall
- Departments of Anesthesiology, Division of Basic Research, Anatomy and Neurobiology, Division of Biomedical Engineering and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO 63110, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Gunchul Shin
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Adrian M Gomez
- Departments of Anesthesiology, Division of Basic Research, Anatomy and Neurobiology, Division of Biomedical Engineering and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Gavin P Schmitz
- Departments of Anesthesiology, Division of Basic Research, Anatomy and Neurobiology, Division of Biomedical Engineering and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Julio M Bernardi
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Chang-O Pyo
- Department of Electrical and Computer Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Sung Il Park
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Catherine M Marcinkiewcz
- Department of Pharmacology and Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, NC 27516, USA
| | - Nicole A Crowley
- Department of Pharmacology and Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, NC 27516, USA
| | - Michael J Krashes
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA; National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA; Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Bradford B Lowell
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas L Kash
- Department of Pharmacology and Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, NC 27516, USA
| | - John A Rogers
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Electrical and Computer Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Michael R Bruchas
- Departments of Anesthesiology, Division of Basic Research, Anatomy and Neurobiology, Division of Biomedical Engineering and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO 63110, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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Ruffle JK. Molecular neurobiology of addiction: what's all the (Δ)FosB about? THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2014; 40:428-37. [PMID: 25083822 DOI: 10.3109/00952990.2014.933840] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The transcription factor ΔFosB is upregulated in numerous brain regions following repeated drug exposure. This induction is likely to, at least in part, be responsible for the mechanisms underlying addiction, a disorder in which the regulation of gene expression is thought to be essential. In this review, we describe and discuss the proposed role of ΔFosB as well as the implications of recent findings. The expression of ΔFosB displays variability dependent on the administered substance, showing region-specificity for different drug stimuli. This transcription factor is understood to act via interaction with Jun family proteins and the formation of activator protein-1 (AP-1) complexes. Once AP-1 complexes are formed, a multitude of molecular pathways are initiated, causing genetic, molecular and structural alterations. Many of these molecular changes identified are now directly linked to the physiological and behavioral changes observed following chronic drug exposure. In addition, ΔFosB induction is being considered as a biomarker for the evaluation of potential therapeutic interventions for addiction.
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Affiliation(s)
- James K Ruffle
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London , London , UK
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11
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Cohen A, Whitfield TW, Kreifeldt M, Koebel P, Kieffer BL, Contet C, George O, Koob GF. Virus-mediated shRNA knockdown of prodynorphin in the rat nucleus accumbens attenuates depression-like behavior and cocaine locomotor sensitization. PLoS One 2014; 9:e97216. [PMID: 24816773 PMCID: PMC4016270 DOI: 10.1371/journal.pone.0097216] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 04/16/2014] [Indexed: 01/10/2023] Open
Abstract
Dynorphins, endogenous opioid peptides that arise from the precursor protein prodynorphin (Pdyn), are hypothesized to be involved in the regulation of mood states and the neuroplasticity associated with addiction. The current study tested the hypothesis that dynorphin in the nucleus accumbens (NAcc) mediates such effects. More specifically, we examined whether knockdown of Pdyn within the NAcc in rats would alter the expression of depressive-like and anxiety-like behavior, as well as cocaine locomotor sensitization. Wistar rats were injected with adeno-associated viral (AAV) vectors encoding either a Pdyn-specific short hairpin RNA (AAV-shPdyn) or a scrambled shRNA (AAV-shScr) as control. Four weeks later, rats were tested for anxiety-like behavior in the elevated plus maze test and depressive-like behavior in the forced swim test (FST). Finally, rats received one daily injection of saline or cocaine (20 mg/kg, i.p.), followed by assessment of locomotion for 4 consecutive days. Following 3 days of abstinence, the rats completed 2 additional daily cocaine/saline locomotor trials. Pdyn knockdown in the NAcc led to a significant reduction in depressive-like behavior in the FST, but had no effect on anxiety-like behavior in the elevated plus maze. Pdyn knockdown did not alter baseline locomotor behavior, the locomotor response to acute cocaine, or the initial sensitization of the locomotor response to cocaine over the first 4 cocaine treatment days. However, following 3 days abstinence the locomotor response to the cocaine challenge returned to their original levels in the AAV-shPdyn rats while remaining heightened in the AAV-shScr rats. These results suggest that dynorphin in a very specific area of the nucleus accumbens contributes to depressive-like states and may be involved in neuroadaptations in the NAcc that contribute to the development of cocaine addiction as a persistent and lasting condition.
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Affiliation(s)
- Ami Cohen
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
| | - Timothy W. Whitfield
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Max Kreifeldt
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Pascale Koebel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Brigitte L. Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Translational Medicine and Neurogenetic Programme, UdS Université de Strasbourg, INSERM U964, CNRS UMR7104, Illkirch, France
| | - Candice Contet
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Olivier George
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - George F. Koob
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
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Trifilieff P, Martinez D. Kappa-opioid receptor signaling in the striatum as a potential modulator of dopamine transmission in cocaine dependence. Front Psychiatry 2013; 4:44. [PMID: 23760592 PMCID: PMC3669800 DOI: 10.3389/fpsyt.2013.00044] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 05/14/2013] [Indexed: 11/13/2022] Open
Abstract
Cocaine addiction is accompanied by a decrease in striatal dopamine signaling, measured as a decrease in dopamine D2 receptor binding as well as blunted dopamine release in the striatum. These alterations in dopamine transmission have clinical relevance, and have been shown to correlate with cocaine-seeking behavior and response to treatment for cocaine dependence. However, the mechanisms contributing to the hypodopaminergic state in cocaine addiction remain unknown. Here we review the positron emission tomography (PET) imaging studies showing alterations in D2 receptor binding potential and dopamine transmission in cocaine abusers and their significance in cocaine-seeking behavior. Based on animal and human studies, we propose that the kappa receptor/dynorphin system, because of its impact on dopamine transmission and upregulation following cocaine exposure, could contribute to the hypodopaminergic state reported in cocaine addiction, and could thus be a relevant target for treatment development.
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Affiliation(s)
- Pierre Trifilieff
- New York State Psychiatric Institute, Columbia University , New York, NY , USA ; NutriNeuro, UMR 1286 INRA, University Bordeaux 2 , Bordeaux , France
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13
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Trigo JM, Martin-García E, Berrendero F, Robledo P, Maldonado R. The endogenous opioid system: a common substrate in drug addiction. Drug Alcohol Depend 2010; 108:183-94. [PMID: 19945803 DOI: 10.1016/j.drugalcdep.2009.10.011] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 09/30/2009] [Accepted: 10/28/2009] [Indexed: 12/17/2022]
Abstract
Drug addiction is a chronic brain disorder leading to complex adaptive changes within the brain reward circuits that involve several neurotransmitters. One of the neurochemical systems that plays a pivotal role in different aspects of addiction is the endogenous opioid system (EOS). Opioid receptors and endogenous opioid peptides are largely distributed in the mesolimbic system and modulate dopaminergic activity within these reward circuits. Chronic exposure to the different prototypical drugs of abuse, including opioids, alcohol, nicotine, psychostimulants and cannabinoids has been reported to produce significant alterations within the EOS, which seem to play an important role in the development of the addictive process. In this review, we will describe the adaptive changes produced by different drugs of abuse on the EOS, and the current knowledge about the contribution of each component of this neurobiological system to their addictive properties.
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Affiliation(s)
- José Manuel Trigo
- Laboratori de Neurofarmacologia, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, PRBB, Barcelona, Spain
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Shin EJ, Jang CG, Bing G, Park DH, Oh CH, Koo KH, Oh KW, Yamada K, Nabeshima T, Kim HC. Prodynorphin gene deficiency potentiates nalbuphine-induced behavioral sensitization and withdrawal syndrome in mice. Drug Alcohol Depend 2009; 104:175-84. [PMID: 19559544 DOI: 10.1016/j.drugalcdep.2009.05.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 05/26/2009] [Accepted: 05/29/2009] [Indexed: 10/20/2022]
Abstract
Dynorphin is the presumed endogenous ligand for the kappa-opioid receptor. The dynorphin gene may play a role in psychotropic agent-mediated behavioral changes via dopaminergic modulation. Therefore, in this study, possible involvement of the dynorphin gene in nalbuphine-mediated behavioral responses was examined using prodynorphin (Pdyn) gene knock-out (-/-) mice. Pdyn gene deficiency potentiates nalbuphine-induced behavioral sensitization of locomotor activity and accumbal c-Fos expression. Administration of nalbuphine induced a significant increase in the dialysate dopamine level in the nucleus accumbens. This increase was more pronounced in the Pdyn (-/-) mice than in the wild-type (WT) mice. In addition, Pdyn (-/-) mice were more vulnerable to the naloxone-precipitated withdrawal syndrome (i.e., teeth chattering, wet dog shakes, forepaw tremors, jumping, weight loss, and global withdrawal score) after repeated treatment with nalbuphine than the WT mice. Consistently, nor-binaltorphimine, a kappa-opioid receptor antagonist, significantly potentiated nalbuphine-induced behavioral effects in WT mice, whereas U-50488H, a kappa-opioid receptor agonist, significantly attenuated these changes in Pdyn (-/-) mice in a dose-dependent manner. Our data suggest that the kappa-opioid receptor/dynorphin system is specifically modulated in response to behavioral sensitization and withdrawal signs induced by nalbuphine.
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Affiliation(s)
- Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, Republic of Korea
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15
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Prodynorphin gene disruption increases the sensitivity to nicotine self-administration in mice. Int J Neuropsychopharmacol 2009; 12:615-25. [PMID: 18937881 DOI: 10.1017/s1461145708009450] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The endogenous opioid system has been reported to participate in nicotine behavioural responses. The aim of the study was to determine the contribution of the endogenous peptides derived from prodynorphin in acute and chronic nicotine responses, mainly those related to its addictive properties. Locomotion and nociception were evaluated after acute nicotine administration in prodynorphin knockout mice. In addition, nicotine rewarding properties were investigated in the place-conditioning and the intravenous self-administration paradigms. The somatic signs of nicotine withdrawal were also analysed after the injection of the nicotinic antagonist mecamylamine in nicotine-dependent mice. The hypolocomotor and antinociceptive effects induced by acute nicotine administration were not modified in knockout (KO) animals. Nicotine also produced similar conditioned place preference in both genotypes. However, a shift to the left in the percentage of acquisition of intravenous nicotine-self administration was observed in prodynorphin KO mice. Indeed, a significant increase in the number of KO mice acquiring this operant behaviour was revealed when low doses of nicotine were used. Nicotine physical dependence was similar in wild-type and KO animals. These findings reveal a specific role of endogenous peptides derived from prodynorphin in nicotine self-administration, probably through the modulation of its aversive effects.
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16
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Schwarzer C. 30 years of dynorphins--new insights on their functions in neuropsychiatric diseases. Pharmacol Ther 2009; 123:353-70. [PMID: 19481570 DOI: 10.1016/j.pharmthera.2009.05.006] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 05/13/2009] [Indexed: 11/28/2022]
Abstract
Since the first description of their opioid properties three decades ago, dynorphins have increasingly been thought to play a regulatory role in numerous functional pathways of the brain. Dynorphins are members of the opioid peptide family and preferentially bind to kappa opioid receptors. In line with their localization in the hippocampus, amygdala, hypothalamus, striatum and spinal cord, their functions are related to learning and memory, emotional control, stress response and pain. Pathophysiological mechanisms that may involve dynorphins/kappa opioid receptors include epilepsy, addiction, depression and schizophrenia. Most of these functions were proposed in the 1980s and 1990s following histochemical, pharmacological and electrophysiological experiments using kappa receptor-specific or general opioid receptor agonists and antagonists in animal models. However, at that time, we had little information on the functional relevance of endogenous dynorphins. This was mainly due to the complexity of the opioid system. Besides actions of peptides from all three classical opioid precursors (proenkephalin, prodynorphin, proopiomelanocortin) on the three classical opioid receptors (delta, mu and kappa), dynorphins were also shown to exert non-opioid effects mainly through direct effects on NMDA receptors. Moreover, discrepancies between the distribution of opioid receptor binding sites and dynorphin immunoreactivity contributed to the difficulties in interpretation. In recent years, the generation of prodynorphin- and opioid receptor-deficient mice has provided the tools to investigate open questions on network effects of endogenous dynorphins. This article examines the physiological, pathophysiological and pharmacological implications of dynorphins in the light of new insights in part obtained from genetically modified animals.
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Affiliation(s)
- Christoph Schwarzer
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr-Str. 1a, A-6020 Innsbruck, Austria.
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17
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Shippenberg TS, Zapata A, Chefer VI. Dynorphin and the pathophysiology of drug addiction. Pharmacol Ther 2007; 116:306-21. [PMID: 17868902 PMCID: PMC2939016 DOI: 10.1016/j.pharmthera.2007.06.011] [Citation(s) in RCA: 276] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Accepted: 06/27/2007] [Indexed: 12/30/2022]
Abstract
Drug addiction is a chronic relapsing disease in which drug administration becomes the primary stimulus that drives behavior regardless of the adverse consequence that may ensue. As drug use becomes more compulsive, motivation for natural rewards that normally drive behavior decreases. The discontinuation of drug use is associated with somatic signs of withdrawal, dysphoria, anxiety, and anhedonia. These consequences of drug use are thought to contribute to the maintenance of drug use and to the reinstatement of compulsive drug use that occurs during the early phase of abstinence. Even, however, after prolonged periods of abstinence, 80-90% of human addicts relapse to addiction, suggesting that repeated drug use produces enduring changes in brain circuits that subserve incentive motivation and stimulus-response (habit) learning. A major goal of addiction research is the identification of the neural mechanisms by which drugs of abuse produce these effects. This article will review data showing that the dynorphin/kappa-opioid receptor (KOPr) system serves an essential function in opposing alterations in behavior and brain neurochemistry that occur as a consequence of repeated drug use and that aberrant activity of this system may not only contribute to the dysregulation of behavior that characterizes addiction but to individual differences in vulnerability to the pharmacological actions of cocaine and alcohol. We will provide evidence that the repeated administration of cocaine and alcohol up-regulates the dynorphin/KOPr system and that pharmacological treatments that target this system may prove effective in the treatment of drug addiction.
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Affiliation(s)
- T S Shippenberg
- Integrative Neuroscience Section, NIH/NIDA Intramural Research Program, 333 Cassell Drive, Baltimore, MD 21224, USA.
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18
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Ray AP, Darmani NA. A histologically derived stereotaxic atlas and substance P immunohistochemistry in the brain of the least shrew (Cryptotis parva) support its role as a model organism for behavioral and pharmacological research. Brain Res 2007; 1156:99-111. [PMID: 17540350 PMCID: PMC2730826 DOI: 10.1016/j.brainres.2007.04.061] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 04/20/2007] [Accepted: 04/20/2007] [Indexed: 02/05/2023]
Abstract
Chemotherapy is an effective treatment but difficult to tolerate due to side effects like vomiting. Studies on the etiology of chemotherapy-related emesis have implicated brainstem nuclei and the neurotransmitter substance P, among other substrates. Since rodents do not vomit, other species have been necessary as alternative models of chemotherapy-induced emesis. Of these, the least shrew (Cryptotis parva) has proven valuable due to its small size, hardiness, and close phylogenetic relationship with primates. However, very little neuroanatomical data on C. parva exist. We used histological and immunohistochemical techniques to provide neuroanatomical data to help validate C. parva as a model organism, especially for emesis research. Brains were sectioned and stained for Nissl substance or myelin, or immunofluorescently labeled for substance P. Sections were photographed, traced, and reconstructed with standardized zero points, and these data used to create a stereotaxic atlas. The brain of C. parva was similar to but smaller than other mammalian brains, with the cerebellum and hippocampus demonstrating the biggest differences. Differences appeared to be related to the small size of the brain and the metabolic compromises required of such a small mammal. Substance P-like immunoreactivity (SPL-IR) was semiquantitatively mapped, and correlated very well with SPL-IR observed in other species. Dense SPL-IR areas included the periaqueductal grey, trigeminal nuclei, dorsal raphe, and emesis-related brainstem nuclei including the area postrema and solitary tract nucleus. These data demonstrate that the anatomical differences between C. parva and other mammals will not preclude its use as a model organism.
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Affiliation(s)
- Andrew P Ray
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E 2nd Street, Pomona, CA 91766, USA.
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19
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Woolley JD, Lee BS, Kim B, Fields HL. Opposing effects of intra-nucleus accumbens mu and kappa opioid agonists on sensory specific satiety. Neuroscience 2007; 146:1445-52. [PMID: 17445988 DOI: 10.1016/j.neuroscience.2007.03.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Revised: 03/02/2007] [Accepted: 03/07/2007] [Indexed: 11/20/2022]
Abstract
Mu opioid (MOP) agonists acting in the nucleus accumbens (NAcc) robustly enhance consumption of palatable foods. In addition, the effect on consumption of palatable foods produced by MOP agonists acting in the NAcc depends on both recent flavor exposure and the availability of a choice between different-flavored foods. In contrast, kappa opioid (KOP) agonists have variable effects on feeding and KOP agonists have MOP opposing behavioral actions when microinjected at several brain sites. We previously demonstrated that NAcc MOP agonists reverse the devaluation (satiety) effect of pre-feeding for a given flavor; in fact, NAcc MOP agonists selectively increase consumption of a recently sampled food. In contrast, in the present study, we found that the selective KOP agonist U50488 injected into the NAcc of rats reduced consumption of a recently sampled flavor while increasing consumption of the flavor that was not pre-fed. Intra-NAcc U50488 did not affect overall consumption or flavor preference in the absence of pre-feeding. The present data, in conjunction with our previous findings, highlight the robust and opposing role of NAcc MOP and KOP opioid receptors in palatability-based food choice and consumption and raise the possibility that an endogenous KOP agonist acting in the NAcc contributes to the phenomenon of sensory specific satiety.
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MESH Headings
- Analgesics/pharmacology
- Analysis of Variance
- Animals
- Behavior, Animal
- Food Preferences/drug effects
- Male
- Nucleus Accumbens/drug effects
- Rats
- Rats, Long-Evans
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/physiology
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/physiology
- Satiety Response/drug effects
- Taste
- Time Factors
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Affiliation(s)
- J D Woolley
- The Ernest Gallo Clinic and Research Center and the Wheeler Center for the Neurobiology of Addiction, Department of Neurology, University of California, San Francisco, San Francisco, CA 94143, USA.
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20
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Haberny SL, Carr KD. Comparison of basal and D-1 dopamine receptor agonist-stimulated neuropeptide gene expression in caudate-putamen and nucleus accumbens of ad libitum fed and food-restricted rats. ACTA ACUST UNITED AC 2005; 141:121-7. [PMID: 16257473 DOI: 10.1016/j.molbrainres.2005.08.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 07/26/2005] [Accepted: 08/03/2005] [Indexed: 10/25/2022]
Abstract
Behavioral studies have demonstrated that chronic food restriction augments the rewarding and motor-activating effects of centrally injected psychostimulants and direct dopamine (DA) receptor agonists. Recently, it has been shown that intracerebroventricular (i.c.v.) injection of the D-1 DA receptor agonist, SKF-82958, produces an enhanced locomotor-activating effect as well as increased activation of striatal ERK 1/2 MAP kinase, CaM kinase II, CREB, and c-fos in food-restricted (FR) relative to ad libitum fed (AL) rats. Striatal neurons that express the D-1 DA receptor coexpress dynorphin and substance P, and CREB is known to couple D-1 DA receptor stimulation to preprodynorphin (ppD) gene expression. The purpose of the present study was to examine possible genomic consequences of FR using real-time quantitative RT-PCR to measure striatal neuropeptide gene expression 3 h after i.c.v. injection of SKF-82958 (20 microg). Results indicate that, in nucleus accumbens (NAc), basal levels of ppD and preprotachykinin (ppT) mRNA are lower in FR than AL rats. This may reflect a decrease in tonic DA transmission during FR which precedes the compensatory upregulation of postsynaptic D-1 DA receptor-mediated cell signaling. In response to SKF-82958 challenge, however, FR subjects displayed greater levels of ppD and ppT mRNA in NAc than did AL subjects. A similar trend was seen in caudate-putamen (CPu). SKF-82958 also increased preproenkephalin (ppE) mRNA in Nac, but not CPu, with no difference between feeding groups. The present findings regarding ppD and ppT are consistent with prior findings of increased behavioral and cellular responses to acute D-1 DA agonist challenge in FR rats. The functional consequences of increased neuropeptide gene expression in response to acute drug challenge remain to be investigated but may include modulation of behavioral effects that emerge with repeated drug exposure, including sensitization, tolerance, and addiction.
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Affiliation(s)
- Sandra L Haberny
- Department of Pharmacology, Millhauser Laboratories, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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21
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Hauser KF, Aldrich JV, Anderson KJ, Bakalkin G, Christie MJ, Hall ED, Knapp PE, Scheff SW, Singh IN, Vissel B, Woods AS, Yakovleva T, Shippenberg TS. Pathobiology of dynorphins in trauma and disease. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 2005; 10:216-35. [PMID: 15574363 PMCID: PMC4304872 DOI: 10.2741/1522] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dynorphins, endogenous opioid neuropeptides derived from the prodynorphin gene, are involved in a variety of normative physiologic functions including antinociception and neuroendocrine signaling, and may be protective to neurons and oligodendroglia via their opioid receptor-mediated effects. However, under experimental or pathophysiological conditions in which dynorphin levels are substantially elevated, these peptides are excitotoxic largely through actions at glutamate receptors. Because the excitotoxic actions of dynorphins require supraphysiological concentrations or prolonged tissue exposure, there has likely been little evolutionary pressure to ameliorate the maladaptive, non-opioid receptor mediated consequences of dynorphins. Thus, dynorphins can have protective and/or proapoptotic actions in neurons and glia, and the net effect may depend upon the distribution of receptors in a particular region and the amount of dynorphin released. Increased prodynorphin gene expression is observed in several disease states and disruptions in dynorphin processing can accompany pathophysiological situations. Aberrant processing may contribute to the net negative effects of dysregulated dynorphin production by tilting the balance towards dynorphin derivatives that are toxic to neurons and/or oligodendroglia. Evidence outlined in this review suggests that a variety of CNS pathologies alter dynorphin biogenesis. Such alterations are likely maladaptive and contribute to secondary injury and the pathogenesis of disease.
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Affiliation(s)
- Kurt F Hauser
- Department of Anatomy and Neurobiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536-0298, USA.
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22
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Bodnar RJ. Endogenous opioids and feeding behavior: a 30-year historical perspective. Peptides 2004; 25:697-725. [PMID: 15165728 DOI: 10.1016/j.peptides.2004.01.006] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Revised: 01/15/2004] [Accepted: 01/16/2004] [Indexed: 11/25/2022]
Abstract
This invited review, based on the receipt of the Third Gayle A. Olson and Richard D. Olson Prize for the publication of the outstanding behavioral article published in the journal Peptides in 2002, examines the 30-year historical perspective of the role of the endogenous opioid system in feeding behavior. The review focuses on the advances that this field has made over the past 30 years as a result of the timely discoveries that were made concerning this important neuropeptide system, and how these discoveries were quickly applied to the analysis of feeding behavior and attendant homeostatic processes. The discoveries of the opioid receptors and opioid peptides, and the establishment of their relevance to feeding behavior were pivotal in studies performed in the 1970s. The 1980s were characterized by the establishment of opioid receptor subtype agonists and antagonists and their relevance to the modulation of feeding behavior as well as by the use of general opioid antagonists in demonstrating the wide array of ingestive situations and paradigms involving the endogenous opioid system. The more recent work from the 1990s to the present, utilizes the advantages created by the cloning of the opioid receptor genes, the development of knockout and knockdown techniques, the systematic utilization of a systems neuroscience approach, and establishment of the reciprocity of how manipulations of opioid peptides and receptors affect feeding behavior with how feeding states affect levels of opioid peptides and receptors. The role of G-protein effector systems in opioid-mediated feeding responses, which was the subject of the prize-winning article, is then reviewed.
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Subprogram, Queens College, City University of New York, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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23
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Svingos AL, Colago EEO. Kappa-Opioid and NMDA glutamate receptors are differentially targeted within rat medial prefrontal cortex. Brain Res 2002; 946:262-71. [PMID: 12137930 DOI: 10.1016/s0006-8993(02)02894-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activation of kappa-opioid receptors (KOR) in the medial prefrontal cortex (mPFC) modulates excitatory transmission, which may involve interactions with N-methyl-D-aspartate (NMDA) glutamate receptors. We investigated possible anatomical correlates of this modulation by using dual labeling electron microscopy to examine the cellular distributions of antibodies raised against KOR and the R1 subunit of the NMDA receptor (NR1). KOR immunoreactivity primarily was localized to plasma and vesicular membranes of axons and axon terminals that were morphologically heterogeneous. A small proportion of KOR immunoreactivity was associated with cytosolic compartments of dendrites and membranes of glial processes. NR1 labeling was mainly postsynaptic, associated most often with membranes of cytoplasmic organelles in cell bodies and large dendrites and plasmalemmal surfaces of distal dendrites. The remaining NR1-labeled profiles were axonal profiles and glial processes. Of all cellular associations between labeled profiles, the majority were KOR-labeled axons that contacted NR1-immunoreactive dendrites or cell bodies. Occasionally the two antigens were colocalized in axon terminals that formed either asymmetric synapses or displayed varicose morphology. KOR and NR1 also were colocalized within dendrites, and rarely were observed in the same cell bodies. Occasionally glial processes coursing adjacent to axo-spinous appositions expressed both KOR and NR1 immunoreactivity. These results indicate that ligand activation of KOR or NMDA receptors differentially modulates excitatory transmission in the mPFC through pre- and postsynaptic mechanisms, respectively. The data also suggest more minor roles for colocalized KOR and NMDA receptors in shared regulation of presynaptic transmitter release, postsynaptic responsivity, and glial function.
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Affiliation(s)
- Adena L Svingos
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Medical College of Cornell University, 411 E. 69th St., New York, NY 10021, USA.
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24
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Svingos AL, Chavkin C, Colago EE, Pickel VM. Major coexpression of kappa-opioid receptors and the dopamine transporter in nucleus accumbens axonal profiles. Synapse 2001; 42:185-92. [PMID: 11746715 DOI: 10.1002/syn.10005] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The behavioral effects of psychostimulants, which are produced at least in part through inhibition of the dopamine transporter (DAT), are modulated by kappa-opioid receptors (KOR) in the nucleus accumbens (Acb). Using electron microscopic immunocytochemistry, we reveal that in the Acb KOR labeling is mainly, and DAT immunoreactivity is exclusively, presynaptic. From 400 KOR-labeled presynaptic structures, including axon terminals, intervaricosities, and small axons, 51% expressed DAT and 29% contacted another population of terminals exclusively labeled for DAT. Within axonal profiles that contained both antigens, DAT and KOR were prominently localized to plasma membrane segments that showed overlapping distributions of the respective immunogold-silver and immunoperoxidase markers. KOR labeling was also localized to membranes of small synaptic vesicles in terminals with or without DAT immunoreactivity. In addition, from 24 KOR-immunoreactive dendritic spines 42% received convergent input from DAT-containing varicosities and unlabeled terminals forming asymmetric, excitatory-type synapses. Our results provide the first ultrastructural evidence that in the Acb, KOR is localized to strategic sites for involvement in the direct presynaptic release and/or reuptake of dopamine. These data also suggest a role for KOR in the presynaptic modulation of other neurotransmitters and in the postsynaptic excitatory responses of single spiny neurons in the Acb. Dual actions on dopamine terminals and their targets in the Acb may account for KOR-mediated attenuation of drug reinforcement and sensitization.
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Affiliation(s)
- A L Svingos
- Department of Neurology and Neuroscience, Division of Neurobiology, Weill Medical College of Cornell University, New York, New York, 10021, USA.
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25
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Persistent alterations in dendrites, spines, and dynorphinergic synapses in the nucleus accumbens shell of rats with neuroleptic-induced dyskinesias. J Neurosci 2001. [PMID: 11027244 DOI: 10.1523/jneurosci.20-20-07798.2000] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Chronic treatment of humans or experimental animals with classical neuroleptic drugs can lead to abnormal, tardive movements that persist long after the drugs are withdrawn. A role in these neuroleptic-induced dyskinesias may be played by a structural change in the shell of the nucleus accumbens where the opioid peptide dynorphin is upregulated in treated rats that show vacuous chewing movements (VCMs). The shell of the nucleus accumbens normally contains a dense plexus of dynorphinergic fibers especially in its caudomedial part. After 27 weeks of haloperidol administration and 18 weeks of withdrawal, the immunoreactive labeling of this plexus is intensified when compared with that after vehicle treatment. In addition, medium spiny neurons here show a significant increase in spine density, dendritic branching, and numbers of terminal segments. In the VCM-positive animals, the dendritic surface area is reduced, and dynorphin-positive terminals contact more spines and form more asymmetrical specializations than do those in animals without the syndrome (VCM-negative and vehicle-treated groups). Persistent, neuroleptic-induced oral dyskinesias could therefore be caused by incontrovertible alterations, involving terminal remodeling or sprouting, to the synaptic connectivity of the accumbal shell.
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26
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Shippenberg TS, Chefer VI, Zapata A, Heidbreder CA. Modulation of the behavioral and neurochemical effects of psychostimulants by kappa-opioid receptor systems. Ann N Y Acad Sci 2001; 937:50-73. [PMID: 11458540 DOI: 10.1111/j.1749-6632.2001.tb03558.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The repeated, intermittent use of cocaine and other drugs of abuse produces profound and often long-lasting alterations in behavior and brain chemistry. It has been suggested that these consequences of drug use play a critical role in drug craving and relapse to addiction. This article reviews the effects of psychostimulant administration on dopaminergic and excitatory amino acid neurotransmission in brain regions comprising the brain's motive circuit and provides evidence that the activation of endogenous kappa-opioid receptor systems in these regions opposes the behavioral and neurochemical consequences of repeated drug use. The role of this opioid system in mediating alterations in mood and affect that occur during abstinence from repeated psychostimulant use are also discussed.
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Affiliation(s)
- T S Shippenberg
- Integrative Neuroscience Unit, NIDA Intramural Research Program, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA.
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27
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Ragnauth A, Moroz M, Bodnar RJ. Multiple opioid receptors mediate feeding elicited by mu and delta opioid receptor subtype agonists in the nucleus accumbens shell in rats. Brain Res 2000; 876:76-87. [PMID: 10973595 DOI: 10.1016/s0006-8993(00)02631-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The nucleus accumbens, and particularly its shell region, is a critical site at which feeding responses can be elicited following direct administration of opiate drugs as well as micro-selective and delta-selective, but not kappa-selective opioid receptor subtype agonists. In contrast to observations of selective and receptor-specific opioid antagonist effects upon corresponding agonist-induced actions in analgesic studies, ventricular administration of opioid receptor subtype antagonists blocks feeding induced by multiple opioid receptor subtype agonists. The present study examined whether feeding responses elicited by either putative mu ([D-Ala(2), NMe-Phe(4), Gly-ol(5)]-enkephalin (DAMGO)), delta(1) ([D-Pen(2), D-Pen(5)]-enkephalin (DPDPE)) or delta(2) ([D-Ala(2), Glu(4)]-deltorphin (Deltorphin)) opioid receptor subtype agonists administered into the nucleus accumbens shell were altered by accumbens pretreatment with either selective mu (beta-funaltrexamine), mu(1) (naloxonazine), delta(1) ([D-Ala(2), Leu(5), Cys(6)]-enkephalin (DALCE)), delta(2) (naltrindole isothiocyanate) or kappa(1) (nor-binaltorphamine) opioid receptor subtype antagonists. Similar magnitudes and durations of feeding responses were elicited by bilateral accumbens administration of either DAMGO (2.5 microg), DPDPE (5 microg) or Deltorphin (5 microg). DAMGO-induced feeding in the nucleus accumbens shell was significantly reduced by accumbens pretreatment of mu, delta(1), delta(2) and kappa(1), but not mu(1) opioid receptor subtype antagonists. DPDPE-induced feeding in the accumbens was significantly reduced by accumbens pretreatment of mu, delta(1), delta(2) and kappa(1), but not mu(1) opioid receptor subtype antagonists. Deltorphin-induced feeding in the accumbens was largely unaffected by accumbens delta(2) antagonist pretreatment, and was significantly enhanced by accumbens mu or kappa(1) antagonist pretreatment. These data indicate different opioid pharmacological profiles for feeding induced by putative mu, delta(1) and delta(2) opioid agonists in the nucleus accumbens shell, as well as the participation of multiple opioid receptor subtypes in the elicitation and maintenance of feeding by these agonists in the nucleus accumbens shell.
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MESH Headings
- Animals
- Eating/drug effects
- Eating/physiology
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Male
- Nucleus Accumbens/drug effects
- Nucleus Accumbens/physiology
- Oligopeptides/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/physiology
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Affiliation(s)
- A Ragnauth
- 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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Smith Y, Kieval J, Couceyro PR, Kuhar MJ. CART peptide-immunoreactive neurones in the nucleus accumbens in monkeys: ultrastructural analysis, colocalization studies, and synaptic interactions with dopaminergic afferents. J Comp Neurol 1999; 407:491-511. [PMID: 10235641 DOI: 10.1002/(sici)1096-9861(19990517)407:4<491::aid-cne3>3.0.co;2-0] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cocaine- and amphetamine-regulated transcript (CART) is a novel mRNA whose level of expression was found to be increased in the striatum after acute administration of psychomotor stimulants in rats. To define better the potential role of CART peptides in behavioural and physiologic changes induced by psychomotor stimulants, we analyzed the distribution, ultrastructural features, synaptic connectivity, and transmitter content of CART peptide-immunoreactive neurones in the nucleus accumbens in monkeys. Medium-sized CART peptide-immunoreactive neurones within a rich plexus of labelled varicosities were found mostly in the medial division of the shell of the nucleus accumbens in monkeys. At the electron microscope level, CART peptide immunoreactivity was exclusively associated with neuronal structures that included perikarya, dendrites, spines as well as nerve terminals packed with electron-lucent and dense-core vesicles. Most CART peptide-containing somata displayed the ultrastructural features of striatal output neurones. The majority of labelled terminals formed symmetric axodendritic synapses and displayed gamma-aminobutyric acid (GABA) immunoreactivity. CART peptide-immunoreactive somata were not immunoreactive for parvalbumin and somatostatin, two markers of striatal interneurones, nor for calbindin D-28k, a marker of a subpopulation of projection neurones. In double-immunostained sections, CART peptide-immunoreactive dendrites were found to be contacted by tyrosine hydroxylase-positive terminals which displayed the ultrastructural features of dopamine-containing boutons. These findings strongly suggest that CART peptides may be a cotransmitter with GABA in a subpopulation of projection neurones in the monkey accumbens. Furthermore, the fact that CART peptide-immunoreactive neurones receive direct synaptic inputs from dopaminergic afferents and are particularly abundant in the caudomedial division of the shell of the nucleus accumbens suggest that CART peptides might be involved in neuronal and behavioural changes that underlie addiction to psychomotor stimulants and feeding in primates.
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Affiliation(s)
- Y Smith
- Yerkes Regional Primate Research Center, Department of Neurology, Emory University, Atlanta, Georgia 30322, USA.
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Abstract
The nucleus accumbens (Acb) is prominently involved in the aversive behavioral aspects of kappa-opioid receptor (KOR) agonists, including its endogenous ligand dynorphin (Dyn). We examined the ultrastructural immunoperoxidase localization of KOR and immunogold labeling of Dyn to determine the major cellular sites for KOR activation in this region. Of 851 KOR-labeled structures sampled from a total area of 10,457 microm2, 63% were small axons and morphologically heterogenous axon terminals, 31% of which apposed Dyn-labeled terminals or also contained Dyn. Sixty-eight percent of the KOR-containing axon terminals formed punctate-symmetric or appositional contacts with unlabeled dendrites and spines, many of which received convergent input from terminals that formed asymmetric synapses. Excitatory-type terminals that formed asymmetric synapses with dendritic spines comprised 21% of the KOR-immunoreactive profiles. Dendritic spines within the neuropil were the major nonaxonal structures that contained KOR immunoreactivity. These spines also received excitatory-type synapses from unlabeled terminals and were apposed by Dyn-containing terminals. These results provide ultrastructural evidence that in the Acb shell (AcbSh), KOR agonists play a primary role in regulating the presynaptic release of Dyn and other neuromodulators that influence the output of spiny neurons via changes in the presynaptic release of or the postsynaptic responses to excitatory amino acids. The cellular distribution of KOR complements those described previously for the reward-associated mu- and delta-opioid receptors in the Acb shell.
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Koylu EO, Couceyro PR, Lambert PD, Kuhar MJ. Cocaine- and amphetamine-regulated transcript peptide immunohistochemical localization in the rat brain. J Comp Neurol 1998. [DOI: 10.1002/(sici)1096-9861(19980202)391:1<115::aid-cne10>3.0.co;2-x] [Citation(s) in RCA: 366] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hermanson O, Telkov M, Geijer T, Hallbeck M, Blomqvist A. Preprodynorphin mRNA-expressing neurones in the rat parabrachial nucleus: subnuclear localization, hypothalamic projections and colocalization with noxious-evoked fos-like immunoreactivity. Eur J Neurosci 1998; 10:358-67. [PMID: 9753144 DOI: 10.1046/j.1460-9568.1998.00021.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The dorsal lateral subnucleus of the rat pontine parabrachial nucleus is a major target for ascending nociceptive information from the spinal cord. With in situ hybridization histochemistry, using a radiolabelled cRNA probe, we demonstrate that neurones in and near the dorsal lateral subnucleus express preprodynorphin mRNA. The cRNA probe was constructed from a PCR product amplified from rat genomic DNA. Sequencing of the PCR product revealed that it corresponded to the sequence 466-1101 of the rat preprodynorphin gene exon 4. Tract tracing experiments, using injection of cholera toxin subunit B into the hypothalamic median preoptic nucleus, showed a retrograde labelling pattern of neurones in the parabrachial nucleus that was almost identical to that of the preprodynorphin mRNA expressing neurones. Double-labelling, combining immunohistochemical detection of tracer and in situ hybridization, revealed that the retrogradely labelled neurones expressed preprodynorphin mRNA. A similar double-labelling, combining in situ hybridization with immunohistochemical detection of noxious-evoked fos following formalin injection into one hindpaw of awake animals, showed that almost all fos-immunoreactive neurones in the dorsal lateral parabrachial subnucleus also expressed preprodynorphin mRNA. Quantitative analysis suggested that the evoked fos immunoreactivity was accompanied by an increased preprodynorphin mRNA expression. The findings provide evidence that neurones in the dorsal lateral subnucleus produce dynorphin and project to the median preoptic nucleus, and that noxious stimulation in awake animals synaptically activates the dynorphinergic neurones in this subnucleus. These observations are consistent with the idea of a functional and chemical heterogeneity among different parabrachial subnuclei that serves to produce specific homeostatic responses to stimuli that changes the physiological status of the organism, including tissue damage.
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Affiliation(s)
- O Hermanson
- Division of Cell Biology, Faculty of Health Sciences, Linköping University, Sweden.
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Smith Y, Koylu EO, Couceyro P, Kuhar MJ. Ultrastructural localization of CART (cocaine- and amphetamine-regulated transcript) peptides in the nucleus accumbens of monkeys. Synapse 1997; 27:90-4. [PMID: 9268069 DOI: 10.1002/(sici)1098-2396(199709)27:1<90::aid-syn10>3.0.co;2-v] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CART (cocaine- and amphetamine-regulated transcript) peptides are proposed to play a role in the action of psychostimulants as neurotransmitters/neuromodulators. In the present study, we demonstrate that the shell of the nucleus accumbens, a brain structure involved in drug reinforcement, is densely innervated by a dense plexus of CART peptide-immunoreactive varicose fibers in register with immunoreactive perikarya in monkeys. At the electron microscopic level, varicosities appeared as immunoreactive axon terminals packed with round electron-lucent vesicles and a variable number of darkly stained dense-core vesicles that formed symmetric synapses with dendrites. These findings suggest that CART peptides may be a cotransmitter with gamma aminobutyric acid (GABA) in intrinsic axon collaterals of striatal projection neurons or interneurons in the primate nucleus accumbens.
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Affiliation(s)
- Y Smith
- Yerkes Regional Primate Research Center, Division of Neuroscience, Emory University, Atlanta, Georgia 30322, USA.
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Shippenberg TS, Rea W. Sensitization to the behavioral effects of cocaine: modulation by dynorphin and kappa-opioid receptor agonists. Pharmacol Biochem Behav 1997; 57:449-55. [PMID: 9218269 DOI: 10.1016/s0091-3057(96)00450-9] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Several lines of evidence suggest an involvement of the mesolimbic dopamine (DA) system in the mediation of psychostimulant-induced sensitization. It is also apparent that endogenous opioid peptide systems can modulate the activity of this same DA system. Psychostimulant-induced alterations in opioid peptide gene expression have also been reported. In this review, evidence will be presented that demonstrates that the administration of kappa-opioid agonists can prevent the initiation of behavioral sensitization to cocaine and that such treatment is also effective in preventing alterations in mesolimbic DA neurotransmission that occur as a consequence of repeated cocaine administration. The putative role of opioid-DA interactions in the modulation of psychostimulant-induced sensitization will also be discussed.
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Affiliation(s)
- T S Shippenberg
- Brain Imaging Section, NIDA Division of Intramural Research, Baltimore, MD 21224, USA
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Lynn RB, Bechtold LS, Miselis RR. Ultrastructure of bombesin-like immunoreactive nerve terminals in the nucleus of the solitary tract and the dorsal motor nucleus. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1997; 62:174-82. [PMID: 9051626 DOI: 10.1016/s0165-1838(96)00125-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Bombesin (gastrin-releasing peptide 14-27) inhibits gastric function and feeding when microinjected into the nucleus of the solitary tract (NTS)/dorsal motor nucleus of the vagus (DMV) complex. We performed a preembedding immunoelectron microscopic study in rats to describe the bombesin containing nerve terminals and to characterize their postsynaptic structures. 228 bombesin-L1 nerve terminals which made synaptic contacts in the NTS/DMV complex were studied. Labeling was heaviest over dense core vesicles and lighter over small clear vesicles. The dense core vesicles were typically located along the plasmalemma away from the synaptic face, a finding that is typical of neuropeptide containing nerve terminals. The postsynaptic structures were most often medium sized dendrites (56%) and small sized dendrites (27%), with similar percentages in the NTS and DMV. In the DMV, synapses on cell bodies (8%) were more frequent than in the NTS (1%). In the NTS, synapses on dendritic spines (10%) were more frequent than in the DMV (4%). Only a single axo-axonal contact was identified. These findings add to the increasing body of evidence that bombesin is a neurotransmitter/neuromodulator in the NTS/DMV complex. Bombesin rarely makes presynaptic (axo-axonal) contacts that might inhibit the release of excitatory neurotransmitters, but rather makes postsynaptic contacts potentially effecting vagal motoneurons.
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Affiliation(s)
- R B Lynn
- Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Steiner H, Gerfen CR. Dynorphin regulates D1 dopamine receptor-mediated responses in the striatum: relative contributions of pre- and postsynaptic mechanisms in dorsal and ventral striatum demonstrated by altered immediate-early gene induction. J Comp Neurol 1996; 376:530-41. [PMID: 8978468 DOI: 10.1002/(sici)1096-9861(19961223)376:4<530::aid-cne3>3.0.co;2-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Dynorphin, an endogenous kappa opioid receptor ligand, acts in the striatum to regulate the response of striatonigral neurons to D1 dopamine receptor stimulation. We investigated the relative contributions of both presynaptic kappa receptors on dopamine terminals and postsynaptic kappa receptors on striatal neurons by analyzing opioid regulation of D1 effects in the absence of presynaptic kappa receptors, after 6-hydroxydopamine depletion of striatal dopamine. D1-receptor-mediated immediate-early gene induction was measured by using in situ hybridization histochemistry. First, repeated treatment with the D1-receptor agonist SKF-38393 (2 mg/kg/day, 3-14 days) was used to increase dynorphin levels in rats with dopamine depletions. In the nucleus accumbens, increased dynorphin expression was accompanied by reduced induction of the immediate-early genes c-fos and zif 268 by SKF-38393. In contrast, in dorsal/lateral aspects of the dopamine-depleted striatum, this D1 response was sustained despite a large increase in dynorphin expression. These results are consistent with a requirement of dopamine terminals (presynaptic kappa receptors) for the inhibitory action of dynorphin in the dorsal/lateral striatum, but not in the ventral striatum. Second, the kappa receptor agonist spiradoline (1-10 mg/kg) reduced c-fos and zif 268 induction by SKF-39393 (2.5 mg/kg) preferentially in ventral parts of the dopamine-depleted striatum, which contain higher levels of kappa receptor mRNA and binding. These results also indicate that postsynaptic kappa receptors contribute to the inhibition of the D1 response at least in the ventral striatum. Together, these results indicate that dynorphin in the striatum functions to regulate dopamine input to striatonigral neurons, acting at both pre- and postsynaptic sites, and that the relative contributions of these mechanisms differ between dorsal and ventral striatal regions.
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Affiliation(s)
- H Steiner
- Laboratory of Neurophysiology, National Institute of Mental Health, Bethesda, Maryland 20892, USA
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Delle Donne KT, Sesack SR, Pickel VM. Ultrastructural immunocytochemical localization of neurotensin and the dopamine D2 receptor in the rat nucleus accumbens. J Comp Neurol 1996; 371:552-66. [PMID: 8841909 DOI: 10.1002/(sici)1096-9861(19960805)371:4<552::aid-cne5>3.0.co;2-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The neuroleptic-like effects of neurotensin (NT) are thought to be due to interactions with dopamine (DA) acting primarily at D2 receptors within the nucleus accumbens septi (Acb). Using electron microscopic dual labeling immunocytochemistry, we sought to demonstrate cellular substrates for functional interactions involving NT and DA D2 receptors in the adult rat Acb. Peroxidase reaction product representing D2 receptor-like immunoreactivity (D2-LI) was seen along membranes of Golgi lamellae and multivesicular bodies of perikarya containing immunogold labeling representing NT-LI. Dually labeled somata usually contained highly indented nuclei, a characteristic of aspiny neurons. Dendrites also occasionally colocalized the two immunomarkers. Other somata, dendrites, and all axon terminals were singly labeled with either NT-LI or D2-LI. In distinct sets of terminals, NT-LI was commonly associated with large, dense-cored vesicles, whereas D2-LI was found along the plasmalemma and over nearby small clear vesicles. Each type of terminal comprised approximately 20% of synaptic input to NT-immunoreactive dendrites. Similar proportions of terminals containing NT-LI or D2-LI contacted unlabeled (approximately 55%) or NT-labeled (approximately 35%) dendrites and, occasionally, were observed converging onto common dendrites. Terminals containing NT-LI or D2-LI also were often closely apposed. These findings provide the first ultrastructural evidence that: (1) NT and D2 receptors are colocalized in aspiny neurons and dendrites, (2) NT may produce a direct postsynaptic effect on neurons receiving input from terminals which are presynaptically modulated by DA via D2 receptors, and (3) NT and DA acting at D2 receptors may interact through presynaptic modulation of common axon terminals.
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Affiliation(s)
- K T Delle Donne
- Department of Neurology and Neuroscience, Cornell University Medical College, New York, New York 10021, USA
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