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Brockway DF, Crowley NA. Emerging pharmacological targets for alcohol use disorder. Alcohol 2024:S0741-8329(24)00101-0. [PMID: 39069210 DOI: 10.1016/j.alcohol.2024.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/27/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Alcohol Use Disorder (AUD) remains a challenging condition with limited effective treatment options; however new technology in drug delivery and advancements in pharmacology have paved the way for discovery of novel therapeutic targets. This review explores emerging pharmacological targets that offer new options for the management of AUD, focusing on the potential of somatostatin (SST), vasoactive intestinal peptide (VIP), glucagon-like peptide-1 (GLP-1), nociceptin (NOP), and neuropeptide S (NPS). These targets have been selected based on recent advancements in preclinical and clinical research, which suggest their significant roles in modulating alcohol consumption and related behaviors. SST dampens cortical circuits, and targeting both the SST neurons and the SST peptide itself presents promise for treating AUD and various related comorbidities. VIP neurons are modulated by alcohol and targeting the VIP system presents an unexplored avenue for addressing alcohol exposure at various stages of development. GLP-1 interacts with the dopaminergic reward system and reduces alcohol intake. Nociceptin modulates mesolimbic circuitry and agonism and antagonism of nociceptin receptor offers a complex but promising approach to reducing alcohol consumption. NPS stands out for its anxiolytic-like effects, particularly relevant for the anxiety associated with AUD. This review aims to synthesize the current understanding of these targets, highlighting their potential in developing more effective and personalized AUD therapies, and underscores the importance of continued research in identifying and validating novel targets for treatment of AUD and comorbid conditions.
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Affiliation(s)
- Dakota F Brockway
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
| | - Nicole A Crowley
- Department of Biology, The Pennsylvania State University, University Park, PA, 16802, USA; Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
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2
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Petrella M, Borruto AM, Curti L, Domi A, Domi E, Xu L, Barbier E, Ilari A, Heilig M, Weiss F, Mannaioni G, Masi A, Ciccocioppo R. Pharmacological blockage of NOP receptors decreases ventral tegmental area dopamine neuronal activity through GABA B receptor-mediated mechanism. Neuropharmacology 2024; 248:109866. [PMID: 38364970 DOI: 10.1016/j.neuropharm.2024.109866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/15/2024] [Accepted: 02/05/2024] [Indexed: 02/18/2024]
Abstract
The Nociceptin/Orphanin FQ (N/OFQ) peptide and its receptor NOP are highly expressed within several regions of the mesolimbic system, including the ventral tegmental area (VTA). Evidence indicates that the N/OFQ-NOP receptor system is involved in reward processing and historically it has been proposed that activation of NOP receptors attenuates the motivation for substances of abuse. However, recent findings demonstrated that drug self-administration and relapse to drug-seeking are also attenuated after administration of NOP receptor antagonists. Here, to shed light on the mechanisms through which NOP receptor blockers modulate these processes, we utilized ex vivo patch-clamp recordings to investigate the effect of the selective NOP receptor antagonist LY2817412 on VTA dopaminergic (DA) function in male rats. Results showed that, similar to the endogenous NOP receptor agonist N/OFQ, LY2817412 reduced the spontaneous basal firing discharge of VTA DA neurons. Consistently, we found that NOP receptors are expressed both in VTA DA and GABA cells and that LY2817412 slice perfusion increased GABA release onto VTA DA cells. Finally, in the attempt to dissect the role of postsynaptic and presynaptic NOP receptors, we tested the effect of N/OFQ and LY2817412 in the presence of GABA receptors blockers. Results showed that the effect of LY2817412 was abolished following pretreatment with GABABR, but not GABAAR, blockers. Conversely, inhibition of DA neuronal activity by N/OFQ was unaffected by blockade of GABA receptors. Altogether, these results suggest that both NOP receptor agonists and antagonists can decrease VTA DA neuronal activity, but through distinct mechanisms of action. The effect of NOP receptor antagonists occurs through a GABABR-mediated mechanism while NOP receptor agonists seem to act via a direct effect on VTA DA neurons.
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Affiliation(s)
- Michele Petrella
- School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Anna Maria Borruto
- School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Lorenzo Curti
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Ana Domi
- School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Esi Domi
- School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy; Center for Social and Affective Neuroscience, Institute for Clinical and Experimental Medicine, Linkoping University, Linkoping, 58183, Sweden
| | - Li Xu
- Center for Social and Affective Neuroscience, Institute for Clinical and Experimental Medicine, Linkoping University, Linkoping, 58183, Sweden
| | - Estelle Barbier
- Center for Social and Affective Neuroscience, Institute for Clinical and Experimental Medicine, Linkoping University, Linkoping, 58183, Sweden
| | - Alice Ilari
- School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Markus Heilig
- Center for Social and Affective Neuroscience, Institute for Clinical and Experimental Medicine, Linkoping University, Linkoping, 58183, Sweden
| | - Friedbert Weiss
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | - Guido Mannaioni
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Alessio Masi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Roberto Ciccocioppo
- School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy.
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Li W, Ren Z, Tang Y, Fu Y, Sun S, Ding R, Hou J, Mai Y, Zhan B, Zhu Y, Zuo W, Ye JH, Fu R. Rostromedial tegmental nucleus nociceptin/orphanin FQ (N/OFQ) signaling regulates anxiety- and depression-like behaviors in alcohol withdrawn rats. Neuropsychopharmacology 2023; 48:908-919. [PMID: 36329156 PMCID: PMC10156713 DOI: 10.1038/s41386-022-01482-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 09/24/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
Recent studies indicate that stimulation of the rostromedial tegmental nucleus (RMTg) can drive a negative affective state and that nociceptin/orphanin FQ (N/OFQ) may play a role in affective disorders and drug addiction. The N/OFQ precursor prepronociceptin encoding genes Pnoc are situated in RMTg neurons. To determine whether N/OFQ signaling contributes to the changes in both behavior phenotypes and RMTg activity of alcohol withdrawn (Post-EtOH) rats, we trained adult male Long-Evans rats, randomly assigned into the ethanol and Naïve groups to consume either 20% ethanol or water-only under an intermittent-access procedure. Using the fluorescence in situ hybridization technique combined with retrograde tracing, we show that the ventral tegmental area projecting RMTg neurons express Pnoc and nociceptin opioid peptide (NOP) receptors encoding gene Oprl1. Also, using the laser capture microdissection technique combined with RT-qPCR, we detected a substantial decrease in Pnoc but an increase in Oprl1 mRNA levels in the RMTg of Post-EtOH rats. Moreover, RMTg cFos expression is increased in Post-EtOH rats, which display anxiety- and depression-like behaviors. Intra-RMTg infusion of the endogenous NOP agonist nociceptin attenuates the aversive behaviors in Post-EtOH rats without causing any notable change in Naïve rats. Conversely, intra-RMTg infusion of the NOP selective antagonist [Nphe1]nociceptin(1-13)NH2 elicits anxiety- and depression-like behaviors in Naïve but not Post-EtOH rats. Furthermore, intra-RMTg infusion of nociceptin significantly reduces alcohol consumption. Thus, our results show that the deficiency of RMTg NOP signaling during alcohol withdrawal mediates anxiety- and depression-like behaviors. The intervention of NOP may help those individuals suffering from alcohol use disorders.
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Affiliation(s)
- Wenfu Li
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Zhiheng Ren
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Ying Tang
- Department of Biology, School of Life Science, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Yixin Fu
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Shizhu Sun
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Ruxuan Ding
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Jiawei Hou
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Yunlin Mai
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Bo Zhan
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Yingxin Zhu
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China
| | - Wanhong Zuo
- Department of Anesthesiology, Pharmacology, Physiology & Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ, 07103, USA
| | - Jiang-Hong Ye
- Department of Anesthesiology, Pharmacology, Physiology & Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ, 07103, USA
| | - Rao Fu
- Department of Anatomy, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, Guangdong, 518107, China.
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Margolis EB, Moulton MG, Lambeth PS, O'Meara MJ. The life and times of endogenous opioid peptides: Updated understanding of synthesis, spatiotemporal dynamics, and the clinical impact in alcohol use disorder. Neuropharmacology 2023; 225:109376. [PMID: 36516892 PMCID: PMC10548835 DOI: 10.1016/j.neuropharm.2022.109376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/03/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
The opioid G-protein coupled receptors (GPCRs) strongly modulate many of the central nervous system structures that contribute to neurological and psychiatric disorders including pain, major depressive disorder, and substance use disorders. To better treat these and related diseases, it is essential to understand the signaling of their endogenous ligands. In this review, we focus on what is known and unknown about the regulation of the over two dozen endogenous peptides with high affinity for one or more of the opioid receptors. We briefly describe which peptides are produced, with a particular focus on the recently proposed possible synthesis pathways for the endomorphins. Next, we describe examples of endogenous opioid peptide expression organization in several neural circuits and how they appear to be released from specific neural compartments that vary across brain regions. We discuss current knowledge regarding the strength of neural activity required to drive endogenous opioid peptide release, clues about how far peptides diffuse from release sites, and their extracellular lifetime after release. Finally, as a translational example, we discuss the mechanisms of action of naltrexone (NTX), which is used clinically to treat alcohol use disorder. NTX is a synthetic morphine analog that non-specifically antagonizes the action of most endogenous opioid peptides developed in the 1960s and FDA approved in the 1980s. We review recent studies clarifying the precise endogenous activity that NTX prevents. Together, the works described here highlight the challenges and opportunities the complex opioid system presents as a therapeutic target.
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Affiliation(s)
- Elyssa B Margolis
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, CA, USA; Neuroscience Graduate Program, University of California, San Francisco, CA, USA.
| | - Madelyn G Moulton
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, CA, USA
| | - Philip S Lambeth
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, CA, USA
| | - Matthew J O'Meara
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
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5
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Caminski ES, Antunes FTT, Souza IA, Dallegrave E, Zamponi GW. Regulation of N-type calcium channels by nociceptin receptors and its possible role in neurological disorders. Mol Brain 2022; 15:95. [PMID: 36434658 PMCID: PMC9700961 DOI: 10.1186/s13041-022-00982-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/15/2022] [Indexed: 11/27/2022] Open
Abstract
Activation of nociceptin opioid peptide receptors (NOP, a.k.a. opioid-like receptor-1, ORL-1) by the ligand nociceptin/orphanin FQ, leads to G protein-dependent regulation of Cav2.2 (N-type) voltage-gated calcium channels (VGCCs). This typically causes a reduction in calcium currents, triggering changes in presynaptic calcium levels and thus neurotransmission. Because of the widespread expression patterns of NOP and VGCCs across multiple brain regions, the dorsal horn of the spinal cord, and the dorsal root ganglia, this results in the alteration of numerous neurophysiological features. Here we review the regulation of N-type calcium channels by the NOP-nociceptin system in the context of neurological conditions such as anxiety, addiction, and pain.
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Affiliation(s)
- Emanuelle Sistherenn Caminski
- grid.412344.40000 0004 0444 6202Graduate Program in Health Sciences, Laboratory of Research in Toxicology (LAPETOX), Federal University of Health Sciences of Porto Alegre, Porto Alegre, RS Brazil
| | - Flavia Tasmin Techera Antunes
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Hotchkiss Brain Institute, University of Calgary, Calgary, AB Canada
| | - Ivana Assis Souza
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Hotchkiss Brain Institute, University of Calgary, Calgary, AB Canada
| | - Eliane Dallegrave
- grid.412344.40000 0004 0444 6202Graduate Program in Health Sciences, Laboratory of Research in Toxicology (LAPETOX), Federal University of Health Sciences of Porto Alegre, Porto Alegre, RS Brazil
| | - Gerald W. Zamponi
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Hotchkiss Brain Institute, University of Calgary, Calgary, AB Canada
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Curley DE, Vasaturo-Kolodner TR, Cannella N, Ciccocioppo R, Haass-Koffler CL. Yohimbine as a pharmacological probe for alcohol research: a systematic review of rodent and human studies. Neuropsychopharmacology 2022; 47:2111-2122. [PMID: 35760866 PMCID: PMC9556614 DOI: 10.1038/s41386-022-01363-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 05/12/2022] [Accepted: 06/02/2022] [Indexed: 11/08/2022]
Abstract
Alcohol use disorder (AUD) is a significant public health concern, contributing to a myriad of social, psychological, and physiological issues. Despite substantial efforts within the alcohol research field, promising preclinical findings have failed to translate to clinical use, highlighting the necessity to develop safe and effective pharmacological probes with the ability to be used in preclinical and clinical research. Yohimbine, an α2 adrenergic receptor antagonist, is a well-validated pharmacological tool that has been widely employed in alcohol studies to evaluate noradrenergic activation. This scoping systematic review examines published literature in rodent and human studies involving the use of yohimbine relevant to alcohol research. We conducted a systematic literature review of MEDLINE, Embase, Web of Science Core Collection, CINAHL, PsycInfo, and Cochrane Central Register of Controlled Trials to identify: (1) Experimental Characteristics and Methodology, (2) Sex Differences, (3) Neurochemical Systems and Brain Regions, and (4) Discussion of Applications for Medication Development. Sixty-seven (62 preclinical and 5 clinical) studies were identified meeting the stated criteria, comprising extensive evidence supporting the use of yohimbine as a safe, titratable pharmacological agent for translational alcohol research. Support for the use of yohimbine as a fully translational tool, however, is hindered by limited available findings from human laboratory studies, as well as a dearth of studies examining sex differences in yohimbine's mechanistic actions. Additional consideration should be given to further translational modeling, ideally allowing for parallel preclinical and clinical assessment of yohimbine, methodological assessment of neurochemical systems and brain regions.
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Affiliation(s)
- Dallece E Curley
- Center for Alcohol and Addiction Studies, Brown University, Providence, RI, USA
- Neuroscience Graduate Program, Department of Neuroscience, Brown University, Providence, RI, USA
| | - Talia R Vasaturo-Kolodner
- Center for Alcohol and Addiction Studies, Brown University, Providence, RI, USA
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Nazzareno Cannella
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Roberto Ciccocioppo
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Carolina L Haass-Koffler
- Center for Alcohol and Addiction Studies, Brown University, Providence, RI, USA.
- Department of Psychiatry and Human Behavior, Warren Alpert Medical School, Brown University, Providence, RI, USA.
- Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, RI, USA.
- Carney Institute for Brain Science, Brown University, Providence, RI, USA.
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Mineur YS, Garcia-Rivas V, Thomas MA, Soares AR, McKee SA, Picciotto MR. Sex differences in stress-induced alcohol intake: a review of preclinical studies focused on amygdala and inflammatory pathways. Psychopharmacology (Berl) 2022; 239:2041-2061. [PMID: 35359158 PMCID: PMC9704113 DOI: 10.1007/s00213-022-06120-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/14/2022] [Indexed: 02/06/2023]
Abstract
Clinical studies suggest that women are more likely than men to relapse to alcohol drinking in response to stress; however, the mechanisms underlying this sex difference are not well understood. A number of preclinical behavioral models have been used to study stress-induced alcohol intake. Here, we review paradigms used to study effects of stress on alcohol intake in rodents, focusing on findings relevant to sex differences. To date, studies of sex differences in stress-induced alcohol drinking have been somewhat limited; however, there is evidence that amygdala-centered circuits contribute to effects of stress on alcohol seeking. In addition, we present an overview of inflammatory pathways leading to microglial activation that may contribute to alcohol-dependent behaviors. We propose that sex differences in neuronal function and inflammatory signaling in circuits centered on the amygdala are involved in sex-dependent effects on stress-induced alcohol seeking and suggest that this is an important area for future studies.
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Affiliation(s)
- Yann S Mineur
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Vernon Garcia-Rivas
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Merrilee A Thomas
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Alexa R Soares
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
- Yale Interdepartmental Neuroscience Program, New Haven, CT, USA
| | - Sherry A McKee
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Marina R Picciotto
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA.
- Yale Interdepartmental Neuroscience Program, New Haven, CT, USA.
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Domi A, Lunerti V, Petrella M, Domi E, Borruto AM, Ubaldi M, Weiss F, Ciccocioppo R. Genetic deletion or pharmacological blockade of nociceptin/orphanin FQ receptors in the ventral tegmental area attenuates nicotine-motivated behaviour. Br J Pharmacol 2022; 179:2647-2658. [PMID: 34854073 PMCID: PMC9081114 DOI: 10.1111/bph.15762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE The nociceptin/orphanin FQ (N/OFQ)-nociceptin opioid-like peptide (NOP) receptor system is widely distributed in the brain and pharmacological activation of this system revealed therapeutic potential in animal models of substance use disorder. Studies also showed that genetic deletion or pharmacological blockade of NOP receptors confer resistance to the development of alcohol abuse. Here, we have used a genetic and pharmacological approach to evaluate the therapeutic potential of NOP antagonism in smoking cessation. EXPERIMENTAL APPROACH Constitutive NOP receptor knockout rats (NOP-/- ) and their wild-type counterparts (NOP+/+ ) were tested over a range of behaviours to characterize their motivation for nicotine. We next explored the effects of systemic administration of the NOP receptor antagonist LY2817412 (1.0 & 3.0 mg·kg-1 ) on nicotine self-administration. NOP receptor blockade was further evaluated at the brain circuitry level, by microinjecting LY2817412 (3.0 & 6.0 μg·μl-1 ) into the ventral tegmental area (VTA), nucleus accumbens (NAc) and central amygdala (CeA). KEY RESULTS Genetic NOP receptor deletion resulted in decreased nicotine intake, decreased motivation to self-administer and attenuation of cue-induced nicotine reinstatement. LY2817412 reduced nicotine intake in NOP+/+ but not in NOP-/- rats, confirming that its effect is mediated by inhibition of NOP transmission. Finally, injection of LY2817412 into the VTA but not into the NAc or CeA decreased nicotine self-administration. CONCLUSIONS AND IMPLICATIONS These findings indicate that inhibition of NOP transmission attenuates the motivation for nicotine through mechanisms involving the VTA and suggest that NOP receptor antagonism may represent a potential treatment for smoking cessation.
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Affiliation(s)
- Ana Domi
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Veronica Lunerti
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Michele Petrella
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Esi Domi
- Center for Social and Affective Neuroscience, Institute for Clinical and Experimental Medicine, Linkoping University, Linkoping 58183, Sweden
| | - Anna Maria Borruto
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Massimo Ubaldi
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Friedbert Weiss
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | - Roberto Ciccocioppo
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
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