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Iemolo A, De Risi M, Giordano N, Torromino G, Somma C, Cavezza D, Colucci M, Mancini M, de Iure A, Granata R, Picconi B, Calabresi P, De Leonibus E. Synaptic mechanisms underlying onset and progression of memory deficits caused by hippocampal and midbrain synucleinopathy. NPJ Parkinsons Dis 2023; 9:92. [PMID: 37328503 DOI: 10.1038/s41531-023-00520-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 05/15/2023] [Indexed: 06/18/2023] Open
Abstract
Cognitive deficits, including working memory, and visuospatial deficits are common and debilitating in Parkinson's disease. α-synucleinopathy in the hippocampus and cortex is considered as the major risk factor. However, little is known about the progression and specific synaptic mechanisms underlying the memory deficits induced by α-synucleinopathy. Here, we tested the hypothesis that pathologic α-Synuclein (α-Syn), initiated in different brain regions, leads to distinct onset and progression of the pathology. We report that overexpression of human α-Syn in the murine mesencephalon leads to late onset memory impairment and sensorimotor deficits accompanied by reduced dopamine D1 expression in the hippocampus. In contrast, human α-Syn overexpression in the hippocampus leads to early memory impairment, altered synaptic transmission and plasticity, and decreased expression of GluA1 AMPA-type glutamate receptors. These findings identify the synaptic mechanisms leading to memory impairment induced by hippocampal α-synucleinopathy and provide functional evidence of the major neuronal networks involved in disease progression.
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Affiliation(s)
- Attilio Iemolo
- Telethon Institute of Genetics and Medicine, Via dei Campi Flegrei 34, Pozzuoli, Naples, Italy
- Institute of Genetics and Biophysics (IGB), Consiglio Nazionale delle Ricerche (CNR), via Pietro Castellino 111, Naples, Italy
| | - Maria De Risi
- Telethon Institute of Genetics and Medicine, Via dei Campi Flegrei 34, Pozzuoli, Naples, Italy
- Institute of Biochemistry and Cell Biology, Consiglio Nazionale delle Ricerche (CNR), Via Ramarini 33, Monterotondo Scalo, Rome, Italy
| | - Nadia Giordano
- Telethon Institute of Genetics and Medicine, Via dei Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Giulia Torromino
- Institute of Biochemistry and Cell Biology, Consiglio Nazionale delle Ricerche (CNR), Via Ramarini 33, Monterotondo Scalo, Rome, Italy
- University of Naples Federico II, Department of Humanistic Studies, Naples, Italy
| | - Cristina Somma
- Telethon Institute of Genetics and Medicine, Via dei Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Diletta Cavezza
- Institute of Biochemistry and Cell Biology, Consiglio Nazionale delle Ricerche (CNR), Via Ramarini 33, Monterotondo Scalo, Rome, Italy
| | - Martina Colucci
- Telethon Institute of Genetics and Medicine, Via dei Campi Flegrei 34, Pozzuoli, Naples, Italy
- Institute of Genetics and Biophysics (IGB), Consiglio Nazionale delle Ricerche (CNR), via Pietro Castellino 111, Naples, Italy
| | - Maria Mancini
- Institute of Neuroscience (IN), Consiglio Nazionale delle Ricerche (CNR), via Raoul Follereau 3, Vedano al Lambro, Monza e Brianza, Italy
| | - Antonio de Iure
- Lab. Experimental Neurophysiology, IRCCS San Raffaele, Rome, 00166, Italy
| | - Rocco Granata
- Institute of Biochemistry and Cell Biology, Consiglio Nazionale delle Ricerche (CNR), Via Ramarini 33, Monterotondo Scalo, Rome, Italy
| | - Barbara Picconi
- Lab. Experimental Neurophysiology, IRCCS San Raffaele, Rome, 00166, Italy
- Telematic University San Raffaele, Rome, 00166, Italy
| | - Paolo Calabresi
- Neurological Clinic, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, 00168, Rome, Italy
- Neurology, Department of Neuroscience, Faculty of Medicine, Università Cattolica del "Sacro Cuore", 00168, Rome, Italy
| | - Elvira De Leonibus
- Telethon Institute of Genetics and Medicine, Via dei Campi Flegrei 34, Pozzuoli, Naples, Italy.
- Institute of Genetics and Biophysics (IGB), Consiglio Nazionale delle Ricerche (CNR), via Pietro Castellino 111, Naples, Italy.
- Institute of Biochemistry and Cell Biology, Consiglio Nazionale delle Ricerche (CNR), Via Ramarini 33, Monterotondo Scalo, Rome, Italy.
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Zuo Y, Iemolo A, Montilla-Perez P, Li HR, Yang X, Telese F. Chronic adolescent exposure to cannabis in mice leads to sex-biased changes in gene expression networks across brain regions. Neuropsychopharmacology 2022; 47:2071-2080. [PMID: 35995972 PMCID: PMC9556757 DOI: 10.1038/s41386-022-01413-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 07/06/2022] [Accepted: 07/25/2022] [Indexed: 11/17/2022]
Abstract
During adolescence, frequent and heavy cannabis use can lead to serious adverse health effects and cannabis use disorder (CUD). Rodent models of adolescent exposure to the main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), mimic the behavioral alterations observed in adolescent users. However, the underlying molecular mechanisms remain largely unknown. Here, we treated female and male C57BL6/N mice with high doses of THC during early adolescence and assessed their memory and social behaviors in late adolescence. We then profiled the transcriptome of five brain regions involved in cognitive and addiction-related processes. We applied gene coexpression network analysis and identified gene coexpression modules, termed cognitive modules, that simultaneously correlated with THC treatment and memory traits reduced by THC. The cognitive modules were related to endocannabinoid signaling in the female dorsal medial striatum, inflammation in the female ventral tegmental area, and synaptic transmission in the male nucleus accumbens. Moreover, cross-brain region module-module interaction networks uncovered intra- and inter-region molecular circuitries influenced by THC. Lastly, we identified key driver genes of gene networks associated with THC in mice and genetic susceptibility to CUD in humans. This analysis revealed a common regulatory mechanism linked to CUD vulnerability in the nucleus accumbens of females and males, which shared four key drivers (Hapln4, Kcnc1, Elavl2, Zcchc12). These genes regulate transcriptional subnetworks implicated in addiction processes, synaptic transmission, brain development, and lipid metabolism. Our study provides novel insights into disease mechanisms regulated by adolescent exposure to THC in a sex- and brain region-specific manner.
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Affiliation(s)
- Yanning Zuo
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Neuroscience Interdepartmental Program, University of California Los Angeles, Los Angeles, CA USA ,grid.266100.30000 0001 2107 4242Department of Medicine, University of California, San Diego, CA USA
| | - Attilio Iemolo
- grid.266100.30000 0001 2107 4242Department of Medicine, University of California, San Diego, CA USA
| | - Patricia Montilla-Perez
- grid.266100.30000 0001 2107 4242Department of Medicine, University of California, San Diego, CA USA
| | - Hai-Ri Li
- grid.266100.30000 0001 2107 4242Department of Medicine, University of California, San Diego, CA USA
| | - Xia Yang
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Brain Research Institute, University of California, Los Angeles, CA USA
| | - Francesca Telese
- Department of Medicine, University of California, San Diego, CA, USA.
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de Guglielmo G, Iemolo A, Nur A, Turner A, Montilla-Perez P, Martinez A, Crook C, Roberts A, Telese F. Reelin deficiency exacerbates cocaine-induced hyperlocomotion by enhancing neuronal activity in the dorsomedial striatum. Genes Brain Behav 2022; 21:e12828. [PMID: 35906757 PMCID: PMC9744517 DOI: 10.1111/gbb.12828] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/15/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022]
Abstract
The Reln gene encodes for the extracellular glycoprotein Reelin, which regulates several brain functions from development to adulthood, including neuronal migration, dendritic growth and branching and synapse formation and plasticity. Human studies have implicated Reelin signaling in several neurodevelopmental and psychiatric disorders. Mouse studies using the heterozygous Reeler (HR) mice have shown that reduced levels of Reln expression are associated with deficits in learning and memory and increased disinhibition. Although these traits are relevant to substance use disorders, the role of Reelin in cellular and behavioral responses to addictive drugs remains largely unknown. Here, we compared HR mice to wild-type (WT) littermate controls to investigate whether Reelin signaling contributes to the hyperlocomotor and rewarding effects of cocaine. After a single or repeated cocaine injections, HR mice showed enhanced cocaine-induced locomotor activity compared with WT controls. This effect persisted after withdrawal. In contrast, Reelin deficiency did not induce cocaine sensitization, and did not affect the rewarding effects of cocaine measured in the conditioned place preference assay. The elevated cocaine-induced hyperlocomotion in HR mice was associated with increased protein Fos expression in the dorsal medial striatum (DMS) compared with WT. Lastly, we performed an RNA fluorescent in situ hybridization experiment and found that Reln was highly co-expressed with the Drd1 gene, which encodes for the dopamine receptor D1, in the DMS. These findings show that Reelin signaling contributes to the locomotor effects of cocaine and improve our understanding of the neurobiological mechanisms underlying the cellular and behavioral effects of cocaine.
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Affiliation(s)
- Giordano de Guglielmo
- Department of Psychiatry, University of California, San Diego, La Jolla, California, USA
| | - Attilio Iemolo
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Aisha Nur
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Andrew Turner
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | | | - Angelica Martinez
- Department of Psychiatry, University of California, San Diego, La Jolla, California, USA
| | - Caitlin Crook
- Department of Psychiatry, University of California, San Diego, La Jolla, California, USA
| | - Amanda Roberts
- Animal Models Core Facility, The Scripps Research Institute, La Jolla, California, USA
| | - Francesca Telese
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
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Long T, Abbasi N, Hernandez JE, Li Y, Sayed IM, Ma S, Iemolo A, Yee BA, Yeo GW, Telese F, Ghosh P, Das S, Huang WJM. RNA binding protein DDX5 directs tuft cell specification and function to regulate microbial repertoire and disease susceptibility in the intestine. Gut 2022; 71:1790-1802. [PMID: 34853057 PMCID: PMC9156727 DOI: 10.1136/gutjnl-2021-324984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 11/12/2021] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Tuft cells residing in the intestinal epithelium have diverse functions. In the small intestine, they provide protection against inflammation, combat against helminth and protist infections, and serve as entry portals for enteroviruses. In the colon, they had been implicated in tumourigenesis. Commitment of intestinal progenitor cells to the tuft cell lineage requires Rho GTPase Cell Division Cycle 42 (CDC42), a Rho GTPase that acts downstream of the epidermal growth factor receptor and wingless-related integration site signalling cascades, and the master transcription factor POU class 2 homeobox 3 (POU2F3). This study investigates how this pathway is regulated by the DEAD box containing RNA binding protein DDX5 in vivo. DESIGN We assessed the role of DDX5 in tuft cell specification and function in control and epithelial cell-specific Ddx5 knockout mice (DDX5ΔIEC) using transcriptomic approaches. RESULTS DDX5ΔIEC mice harboured a loss of intestinal tuft cell populations, modified microbial repertoire, and altered susceptibilities to ileal inflammation and colonic tumourigenesis. Mechanistically, DDX5 promotes CDC42 protein synthesis through a post-transcriptional mechanism to license tuft cell specification. Importantly, the DDX5-CDC42 axis is parallel but distinct from the known interleukin-13 circuit implicated in tuft cell hyperplasia, and both pathways augment Pou2f3 expression in secretory lineage progenitors. In mature tuft cells, DDX5 not only promotes integrin signalling and microbial responses, it also represses gene programmes involved in membrane transport and lipid metabolism. CONCLUSION RNA binding protein DDX5 directs tuft cell specification and function to regulate microbial repertoire and disease susceptibility in the intestine.
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Affiliation(s)
- Tianyun Long
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Nazia Abbasi
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Juan E Hernandez
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Yuxin Li
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Ibrahim M Sayed
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Shengyun Ma
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Attilio Iemolo
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Brian A Yee
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Francesca Telese
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, California, USA
| | - Wendy Jia Men Huang
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
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Iemolo A, Montilla-Perez P, Nguyen J, Risbrough VB, Taffe MA, Telese F. Reelin deficiency contributes to long-term behavioral abnormalities induced by chronic adolescent exposure to Δ9-tetrahydrocannabinol in mice. Neuropharmacology 2021; 187:108495. [PMID: 33582152 DOI: 10.1016/j.neuropharm.2021.108495] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/03/2021] [Accepted: 02/08/2021] [Indexed: 01/03/2023]
Abstract
Cannabis use is widespread among adolescents and has been associated with long-term negative outcomes on neurocognitive functions. However, the factors that contribute to the long-term detrimental effects of cannabis use remain poorly understood. Here, we studied how Reelin deficiency influences the behavior of mice exposed to cannabis during adolescence. Reelin is a gene implicated in the development of the brain and of psychiatric disorders. To this aim, heterozygous Reeler (HR) mice, that express reduced level of Reelin, were chronically injected during adolescence with high doses (10 mg/kg) of Δ9-tetrahydrocannabinol (THC), a major psychoactive component of cannabis. Two weeks after the last injection of THC, mice were tested with multiple behavioral assays, including working memory, social interaction, locomotor activity, anxiety-like responses, stress reactivity, and pre-pulse inhibition. Compared to wild-type (WT), HR mice treated with THC showed impaired social behaviors, elevated disinhibitory phenotypes and increased reactivity to aversive situations, in a sex-specific manner. Overall, these findings show that Reelin deficiency influences behavioral abnormalities caused by heavy consumption of THC during adolescence and suggest that elucidating Reelin signaling will improve our understanding of neurobiological mechanisms underlying behavioral traits relevant to the development of psychiatric conditions.
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Affiliation(s)
- Attilio Iemolo
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | | | - Jacques Nguyen
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Victoria B Risbrough
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA; Center for Excellence in Stress and Mental Health, Veterans Affairs San Diego Healthcare System, San Diego, CA, 92161, USA
| | - Michael A Taffe
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Francesca Telese
- Department of Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
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Iemolo A, Montilla-Perez P, Lai IC, Meng Y, Nolan S, Wen J, Rusu I, Dulcis D, Telese F. A cell type-specific expression map of NCoR1 and SMRT transcriptional co-repressors in the mouse brain. J Comp Neurol 2020; 528:2218-2238. [PMID: 32072640 DOI: 10.1002/cne.24886] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 12/12/2019] [Accepted: 02/12/2020] [Indexed: 12/11/2022]
Abstract
The ability to rapidly change gene expression patterns is essential for differentiation, development, and functioning of the brain. Throughout development, or in response to environmental stimuli, gene expression patterns are tightly regulated by the dynamic interplay between transcription activators and repressors. Nuclear receptor corepressor 1 (NCoR1) and silencing mediator for retinoid or thyroid-hormone receptors (SMRT) are the best characterized transcriptional co-repressors from a molecular point of view. They mediate epigenetic silencing of gene expression in a wide range of developmental and homeostatic processes in many tissues, including the brain. For instance, NCoR1 and SMRT regulate neuronal stem cell proliferation and differentiation during brain development and they have been implicated in learning and memory. However, we still have a limited understanding of their regional and cell type-specific expression in the brain. In this study, we used fluorescent immunohistochemistry to map their expression patterns throughout the adult mouse brain. Our findings reveal that NCoR1 and SMRT share an overall neuroanatomical distribution, and are detected in both excitatory and inhibitory neurons. However, we observed striking differences in their cell type-specific expression in glial cells. Specifically, all oligodendrocytes express NCoR1, but only a subset express SMRT. In addition, NCoR1, but not SMRT, was detected in a subset of astrocytes and in the microglia. These novel observations are corroborated by single cell transcriptomics and emphasize how NCoR1 and SMRT may contribute to distinct biological functions, suggesting an exclusive role of NCoR1 in innate immune responses in the brain.
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Affiliation(s)
- Attilio Iemolo
- Department of Medicine, University of California San Diego, La Jolla, California
| | | | - I-Chi Lai
- Department of Psychiatry, University of California San Diego, La Jolla, California
| | - Yinuo Meng
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Syreeta Nolan
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Junneng Wen
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Iulia Rusu
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Davide Dulcis
- Department of Psychiatry, University of California San Diego, La Jolla, California
| | - Francesca Telese
- Department of Medicine, University of California San Diego, La Jolla, California
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Giordano N, Iemolo A, Mancini M, Cacace F, De Risi M, Latagliata EC, Ghiglieri V, Bellenchi GC, Puglisi-Allegra S, Calabresi P, Picconi B, De Leonibus E. Motor learning and metaplasticity in striatal neurons: relevance for Parkinson's disease. Brain 2019; 141:505-520. [PMID: 29281030 DOI: 10.1093/brain/awx351] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 10/29/2017] [Indexed: 01/08/2023] Open
Abstract
Nigro-striatal dopamine transmission is central to a wide range of neuronal functions, including skill learning, which is disrupted in several pathologies such as Parkinson's disease. The synaptic plasticity mechanisms, by which initial motor learning is stored for long time periods in striatal neurons, to then be gradually optimized upon subsequent training, remain unexplored. Addressing this issue is crucial to identify the synaptic and molecular mechanisms involved in striatal-dependent learning impairment in Parkinson's disease. In this study, we took advantage of interindividual differences between outbred rodents in reaching plateau performance in the rotarod incremental motor learning protocol, to study striatal synaptic plasticity ex vivo. We then assessed how this process is modulated by dopamine receptors and the dopamine active transporter, and whether it is impaired by overexpression of human α-synuclein in the mesencephalon; the latter is a progressive animal model of Parkinson's disease. We found that the initial acquisition of motor learning induced a dopamine active transporter and D1 receptors mediated long-term potentiation, under a protocol of long-term depression in striatal medium spiny neurons. This effect disappeared in animals reaching performance plateau. Overexpression of human α-synuclein reduced striatal dopamine active transporter levels, impaired motor learning, and prevented the learning-induced long-term potentiation, before the appearance of dopamine neuronal loss. Our findings provide evidence of a reorganization of cellular plasticity within the dorsolateral striatum that is mediated by dopamine receptors and dopamine active transporter during the acquisition of a skill. This newly identified mechanism of cellular memory is a form of metaplasticity that is disrupted in the early stage of synucleinopathies, such as Parkinson's disease, and that might be relevant for other striatal pathologies, such as drug abuse.
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Affiliation(s)
- Nadia Giordano
- Institute of Genetics and Biophysics (IGB), National Research Council, Naples, Italy.,Telethon Institute of Genetics and Medicine, Telethon Foundation, Pozzuoli, Italy
| | - Attilio Iemolo
- Institute of Genetics and Biophysics (IGB), National Research Council, Naples, Italy
| | - Maria Mancini
- Laboratory of Neurophysiology, Santa Lucia Foundation, IRCCS, Rome, Italy
| | - Fabrizio Cacace
- Laboratory of Neurophysiology, Santa Lucia Foundation, IRCCS, Rome, Italy
| | - Maria De Risi
- Institute of Genetics and Biophysics (IGB), National Research Council, Naples, Italy.,Telethon Institute of Genetics and Medicine, Telethon Foundation, Pozzuoli, Italy
| | - Emanuele Claudio Latagliata
- Laboratory of Neurophysiology, Santa Lucia Foundation, IRCCS, Rome, Italy.,Department of Psychology, University of Rome La Sapienza, Rome, Italy
| | - Veronica Ghiglieri
- Laboratory of Neurophysiology, Santa Lucia Foundation, IRCCS, Rome, Italy.,Department of Philosophy, Human, Social and Educational Sciences, University of Perugia, Perugia, Italy
| | - Gian Carlo Bellenchi
- Institute of Genetics and Biophysics (IGB), National Research Council, Naples, Italy
| | - Stefano Puglisi-Allegra
- Laboratory of Neurophysiology, Santa Lucia Foundation, IRCCS, Rome, Italy.,Department of Psychology, University of Rome La Sapienza, Rome, Italy
| | - Paolo Calabresi
- Laboratory of Neurophysiology, Santa Lucia Foundation, IRCCS, Rome, Italy.,Department of Medicine, Neurology Unit, University of Perugia, S. Andrea delle Fratte, Perugia, Italy
| | - Barbara Picconi
- Laboratory of Neurophysiology, Santa Lucia Foundation, IRCCS, Rome, Italy
| | - Elvira De Leonibus
- Institute of Genetics and Biophysics (IGB), National Research Council, Naples, Italy.,Telethon Institute of Genetics and Medicine, Telethon Foundation, Pozzuoli, Italy
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Viggiano D, Speranza L, Crispino M, Bellenchi GC, di Porzio U, Iemolo A, De Leonibus E, Volpicelli F, Perrone-Capano C. Information content of dendritic spines after motor learning. Behav Brain Res 2018; 336:256-260. [DOI: 10.1016/j.bbr.2017.09.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/05/2017] [Accepted: 09/08/2017] [Indexed: 12/20/2022]
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Iemolo A, Seiglie M, Blasio A, Cottone P, Sabino V. Pituitary adenylate cyclase-activating polypeptide (PACAP) in the central nucleus of the amygdala induces anxiety via melanocortin receptors. Psychopharmacology (Berl) 2016; 233:3269-77. [PMID: 27376948 PMCID: PMC4982769 DOI: 10.1007/s00213-016-4366-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 06/18/2016] [Indexed: 11/29/2022]
Abstract
RATIONALE Anxiety disorders are the most common mental disorders in the USA. Characterized by feelings of uncontrollable apprehension, they are accompanied by physical, affective, and behavioral symptoms. The neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor PAC1 (PAC1R) are highly expressed in the central nucleus of the amygdala (CeA), and they have gained growing attention for their proposed role in mediating the body's response to stress. OBJECTIVES The aim of this study was to evaluate the anxiogenic effects of PACAP in the CeA and its effects on the hypothalamic-pituitary-adrenal (HPA) axis. Furthermore, the mechanism of action of PACAP in the CeA was investigated. METHODS PACAP was microinfused into the CeA of rats, and its effects in the elevated plus maze (EPM), the defensive withdrawal tests, and plasma corticosterone levels were evaluated. The ability of the melanocortin receptor antagonist SHU9119 to block PACAP effect in the EPM was assessed. RESULTS Intra-CeA PACAP exerted a dose-dependent anxiogenic effect and activated the HPA axis. In contrast, PACAP microinfused into the basolateral nucleus of the amygdala (BlA) had no effect. Finally, the anxiogenic effect of intra-CeA PACAP was prevented by SHU9119. CONCLUSIONS These data prove an anxiogenic role for the PACAP system of the CeA and reveal that the melanocortin receptor 4 (MC4R) system of CeA mediates these effects. Our data provide insights into this neuropeptide system as a mechanism for modulating the behavioral and endocrine response to stress and suggest that dysregulations of this system may contribute to the pathophysiology of anxiety-related disorders.
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Affiliation(s)
- Attilio Iemolo
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
| | - Mariel Seiglie
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
- Graduate Program in Neuroscience, Boston University, Boston, MA, USA
| | - Angelo Blasio
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics and Department of Psychiatry, Boston University School of Medicine, 72 E Concord St, R-612, Boston, MA, 02118, USA.
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Iemolo A, Ferragud A, Cottone P, Sabino V. Pituitary Adenylate Cyclase-Activating Peptide in the Central Amygdala Causes Anorexia and Body Weight Loss via the Melanocortin and the TrkB Systems. Neuropsychopharmacology 2015; 40:1846-55. [PMID: 25649277 PMCID: PMC4839508 DOI: 10.1038/npp.2015.34] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/10/2015] [Accepted: 01/11/2015] [Indexed: 02/03/2023]
Abstract
Growing evidence suggests that the pituitary adenylate cyclase-activating polypeptide (PACAP)/PAC1 receptor system represents one of the main regulators of the behavioral, endocrine, and autonomic responses to stress. Although induction of anorexia is a well-documented effect of PACAP, the central sites underlying this phenomenon are poorly understood. The present studies addressed this question by examining the neuroanatomical, behavioral, and pharmacological mechanisms mediating the anorexia produced by PACAP in the central nucleus of the amygdala (CeA), a limbic structure implicated in the emotional components of ingestive behavior. Male rats were microinfused with PACAP (0-1 μg per rat) into the CeA and home-cage food intake, body weight change, microstructural analysis of food intake, and locomotor activity were assessed. Intra-CeA (but not intra-basolateral amygdala) PACAP dose-dependently induced anorexia and body weight loss without affecting locomotor activity. PACAP-treated rats ate smaller meals of normal duration, revealing that PACAP slowed feeding within meals by decreasing the regularity and maintenance of feeding from pellet-to-pellet; postprandial satiety was unaffected. Intra-CeA PACAP-induced anorexia was blocked by coinfusion of either the melanocortin receptor 3/4 antagonist SHU 9119 or the tyrosine kinase B (TrKB) inhibitor k-252a, but not the CRF receptor antagonist D-Phe-CRF(12-41). These results indicate that the CeA is one of the brain areas through which the PACAP system promotes anorexia and that PACAP preferentially lessens the maintenance of feeding in rats, effects opposite to those of palatable food. We also demonstrate that PACAP in the CeA exerts its anorectic effects via local melanocortin and the TrKB systems, and independently from CRF.
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Affiliation(s)
- Attilio Iemolo
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA,Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Antonio Ferragud
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA,Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA,Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA,Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118 USA, Tel: +1 617 638 4327, Fax: +1 617 638 5668, E-mail: or
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA,Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA,Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118 USA, Tel: +1 617 638 4327, Fax: +1 617 638 5668, E-mail: or
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Seiglie M, Iemolo A, Blasio A, Cottone P, Sabino V. Central Amygdala PACAP in the Behavioral Stress Response. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.615.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mariel Seiglie
- Department of Pharmacology and Psychiatry Boston University School of MedicineBostonMassachusettsUnited States
| | - Attilio Iemolo
- Department of Pharmacology and Psychiatry Boston University School of MedicineBostonMassachusettsUnited States
| | - Angelo Blasio
- Department of Pharmacology and Psychiatry Boston University School of MedicineBostonMassachusettsUnited States
| | - Pietro Cottone
- Department of Pharmacology and Psychiatry Boston University School of MedicineBostonMassachusettsUnited States
| | - Valentina Sabino
- Department of Pharmacology and Psychiatry Boston University School of MedicineBostonMassachusettsUnited States
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Iemolo A, Blasio A, St Cyr SA, Jiang F, Rice KC, Sabino V, Cottone P. CRF-CRF1 receptor system in the central and basolateral nuclei of the amygdala differentially mediates excessive eating of palatable food. Neuropsychopharmacology 2013; 38:2456-66. [PMID: 23748225 PMCID: PMC3799065 DOI: 10.1038/npp.2013.147] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/30/2013] [Accepted: 06/04/2013] [Indexed: 01/27/2023]
Abstract
Highly palatable foods and dieting are major contributing factors for the development of compulsive eating in obesity and eating disorders. We previously demonstrated that intermittent access to palatable food results in corticotropin-releasing factor-1 (CRF1) receptor antagonist-reversible behaviors, which include excessive palatable food intake, hypophagia of regular chow, and anxiety-like behavior. However, the brain areas mediating these effects are still unknown. Male Wistar rats were either fed chow continuously for 7 days/week (Chow/Chow group), or fed chow intermittently 5 days/week, followed by a sucrose, palatable diet 2 days/week (Chow/Palatable group). Following chronic diet alternation, the effects of microinfusing the CRF1 receptor antagonist R121919 (0, 0.5, 1.5 μg/side) in the central nucleus of the amygdala (CeA), the basolateral nucleus of the amygdala (BlA), or the bed nucleus of the stria terminalis (BNST) were evaluated on excessive intake of the palatable diet, chow hypophagia, and anxiety-like behavior. Furthermore, CRF immunostaining was evaluated in the brain of diet cycled rats. Intra-CeA R121919 blocked both excessive palatable food intake and anxiety-like behavior in Chow/Palatable rats, without affecting chow hypophagia. Conversely, intra-BlA R121919 reduced the chow hypophagia in Chow/Palatable rats, without affecting excessive palatable food intake or anxiety-like behavior. Intra-BNST treatment had no effect. The treatments did not modify the behavior of Chow/Chow rats. Immunohistochemistry revealed an increased number of CRF-positive cells in CeA--but not in BlA or BNST--of Chow/Palatable rats, during both withdrawal and renewed access to the palatable diet, compared with controls. These results provide functional evidence that the CRF-CRF1 receptor system in CeA and BlA has a differential role in mediating maladaptive behaviors resulting from palatable diet cycling.
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Affiliation(s)
- Attilio Iemolo
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Angelo Blasio
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Stephen A St Cyr
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Fanny Jiang
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Kenner C Rice
- Chemical Biology Research Branch, National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism, Rockville, MD, USA
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, USA,Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 East Concord Street, R-618, Boston, MA 02118, USA, Tel: +1 617 638 5662, Fax: +1 617 638 5668, E-mail:
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Iemolo A, Cottone P, Sabino V. E.24 - PACAP IN THE CENTRAL NUCLEUS OF THE AMYGDALA REDUCES FOOD INTAKE AND BODY WEIGHT GAIN VIA THE MELANOCORTIN AND THE BDNF/TRKB SYSTEMS. Behav Pharmacol 2013. [DOI: 10.1097/01.fbp.0000434843.61622.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Cottone P, Iemolo A, Narayan AR, Kwak J, Momaney D, Sabino V. The uncompetitive NMDA receptor antagonists ketamine and memantine preferentially increase the choice for a small, immediate reward in low-impulsive rats. Psychopharmacology (Berl) 2013; 226:127-38. [PMID: 23104264 PMCID: PMC3572289 DOI: 10.1007/s00213-012-2898-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 09/23/2012] [Indexed: 02/04/2023]
Abstract
RATIONALE Impulsive behavior is categorically differentiated between impulsive action, the inability to withhold from acting out a response, and impulsive choice, the greater preference for an immediate and smaller reward over a delayed but more advantageous reward. While the effects of N-methyl-D-aspartic acid (NMDA) receptor antagonists on impulsive action have been extensively characterized, there are very few and conflicting reports on the effects of this class of drugs on impulsive choice. OBJECTIVES Using a modified adjusting delay task, we investigated the effects of uncompetitive and competitive blockade of NMDA receptors on impulsive choice. METHODS Male Wistar rats were trained in a modified adjusting delay task, which involved repeated choice between a low reinforcing solution delivered immediately and a highly reinforcing solution delivered after a variable delay. Rats were then administered either the NMDA receptor uncompetitive antagonists ketamine or memantine, or the competitive antagonists D-AP-5 or CGS 19755. RESULTS Ketamine treatment dose-dependently increased impulsive choice, and this effect was selective for low-impulsive but not high-impulsive rats. Similarly, memantine treatment dose-dependently increased impulsive choice with a preferential effect for low-impulsive rats. While D-AP-5 treatment did not affect impulsive choice, CGS 19755 increased impulsivity, however, at the same doses at which it caused a marked response inhibition. CONCLUSIONS NMDA receptor uncompetitive, but not competitive, antagonists significantly increased impulsive choice, preferentially in low-impulsive rats. These findings demonstrate that the effects of NMDA receptor blockade on impulsive choice are not generalizable and depend on the specific mechanism of action of the antagonist used.
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Affiliation(s)
- Pietro Cottone
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Attilio Iemolo
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Aditi R. Narayan
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Jina Kwak
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Duncan Momaney
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
| | - Valentina Sabino
- Department of Pharmacology, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA. Department of Psychiatry, Laboratory of Addictive Disorders, Boston University School of Medicine, 72 E Concord St., R-618, Boston, MA 02118, USA
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Iemolo A, Valenza M, Tozier L, Knapp CM, Kornetsky C, Steardo L, Sabino V, Cottone P. Withdrawal from chronic, intermittent access to a highly palatable food induces depressive-like behavior in compulsive eating rats. Behav Pharmacol 2012; 23:593-602. [PMID: 22854309 PMCID: PMC3934429 DOI: 10.1097/fbp.0b013e328357697f] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The increased availability of highly palatable foods is a major contributing factor toward the development of compulsive eating in obesity and eating disorders. It has been proposed that compulsive eating may develop as a form of self-medication to alleviate the negative emotional state associated with withdrawal from highly palatable foods. This study was aimed at determining whether withdrawal from chronic, intermittent access to a highly palatable food was responsible for the emergence of depressive-like behavior. For this purpose, a group of male Wistar rats was provided a regular chow diet 7 days a week (Chow/Chow), whereas a second group of rats was provided chow for 5 days a week, followed by a 2-day access to a highly palatable sucrose diet (Chow/Palatable). Following 7 weeks of diet alternation, depressive-like behavior was assessed during withdrawal from the highly palatable diet and following renewed access to it, using the forced swim test, the sucrose consumption test, and the intracranial self-stimulation threshold procedure. It was found that Chow/Palatable rats withdrawn from the highly palatable diet showed increased immobility time in the forced swim test and decreased sucrose intake in the sucrose consumption test compared with the control Chow/Chow rats. Interestingly, the increased immobility in the forced swim test was abolished by renewing access to the highly palatable diet. No changes were observed in the intracranial self-stimulation threshold procedure. These results validate the hypothesis that withdrawal from highly palatable food is responsible for the emergence of depressive-like behavior, and they also show that compulsive eating relieves the withdrawal-induced negative emotional state.
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Affiliation(s)
- Attilio Iemolo
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Marta Valenza
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Pharmacology and Human Physiology, University of Bari, Bari
| | - Lisa Tozier
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Clifford M. Knapp
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Conan Kornetsky
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Luca Steardo
- Department of Physiology and Pharmacology, University of Rome La Sapienza, Rome, Italy
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA
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Scoto GM, Aricò G, Iemolo A, Ronsisvalle G, Parenti C. Selective inhibition of the NOP receptor in the ventrolateral periaqueductal gray attenuates the development and the expression of tolerance to morphine-induced antinociception in rats. Peptides 2010; 31:696-700. [PMID: 20067813 DOI: 10.1016/j.peptides.2009.12.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 12/30/2009] [Accepted: 12/30/2009] [Indexed: 12/14/2022]
Abstract
The ventrolateral periaqueductal gray (vlPAG) is a major site of opioid analgesic action and a key locus for the development of morphine tolerance. Previous experimental evidence supports the hypothesis that the brain synthesizes and secretes neuropeptides, which act as a part of the homeostatic system to attenuate the effects of morphine and endogenous opioid peptides. Among the known antiopioid peptides, nociceptin/orphanin FQ (N/OFQ) has been shown to inhibit various opioid effects, especially analgesia. The present study investigated the effect of NOP receptor blockade on the tolerance to morphine antinociception in the vlPAG. Systemic morphine (10mg/kg s.c. twice per day) induced an antinociceptive effect that diminished significantly on the third day when tolerance developed, as quantified by the tail flick and the hot plate tests. Intra vlPAG (i.vlPAG) administration of the NOP receptor antagonist (+/-)-J 113397 restored the opioid's analgesic effect. When (+/-)-J 113397 was administered beginning the first day preceding each morphine administration, tolerance did not develop, but it appeared if the NOP antagonist had been suspended. These data suggest that the N/OFQ in the vlPAG may play a key role in opioid-induced antinociceptive tolerance.
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Affiliation(s)
- Giovanna M Scoto
- Department of Pharmaceutical Sciences-Pharmacology Section, University of Catania, vle A Doria 6, 95125 Catania, Italy.
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