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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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2
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Lutfy K, Hamid A, Zaveri NT. Small molecule NOP agonists reverse locomotor sensitization induced by cocaine in male C57BL/6 mice. Prog Neuropsychopharmacol Biol Psychiatry 2024; 131:110941. [PMID: 38199489 DOI: 10.1016/j.pnpbp.2024.110941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 01/07/2024] [Accepted: 01/07/2024] [Indexed: 01/12/2024]
Abstract
Orphanin FQ/nociceptin (OFQ/N), the endogenous ligand of the nociceptin opioid receptor (NOP) has been shown to block cocaine-induced locomotor sensitization in mice and rats, and also reverses this phenomenon when injected intracerebroventricularly in animals with an established sensitized response. In the present study, we determined whether small-molecule NOP agonists would recapitulate this effect after systemic administration. Male C57BL/6 mice treated with cocaine (15 mg/kg) on days 1-3 and showed locomotor sensitization to the same dose of cocaine on day 8 were injected with vehicle or one of the two NOP agonists (AT-202 and AT-524) (but not cocaine) on days 9-11. On day 15, locomotor sensitization was assessed after a cocaine challenge (15 mg/kg). Subchronic administration of the two NOP agonists to sensitized mice significantly decreased the sensitized response on day 15. In a separate experiment conducted in male and female mice lacking NOP and their wildtype littermates, AT-524 reversed sensitization in male wildtype but not in mice lacking NOP. Further, co-administration of the NOP agonist with cocaine for three days on days 16-18 prevented the development of locomotor sensitization from this cocaine treatment in wild-type but not in NOP knockout mice. However, none of these effects of the NOP agonist was observed in female mice. Together, these results suggest that subchronic repeated administration of small-molecule NOP agonists may reverse adaptive behavioral changes associated with repeated intermittent cocaine treatment in male but not female mice.
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Affiliation(s)
- Kabirullah Lutfy
- College of Pharmacy, Western University of Health Sciences, Pomona, CA 91766, United States of America.
| | - Abdul Hamid
- College of Pharmacy, Western University of Health Sciences, Pomona, CA 91766, United States of America
| | - Nurulain T Zaveri
- Astraea Therapeutics, 320 Logue Avenue, Mountain View, CA, United States of America.
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3
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Meyer ME, Doshi A, Polgar WE, Zaveri NT. Discovery and structure-activity relationships (SAR) of a novel class of 2-substituted N-piperidinyl indole-based nociceptin opioid receptor ligands. Bioorg Med Chem 2023; 92:117421. [PMID: 37573822 PMCID: PMC10491432 DOI: 10.1016/j.bmc.2023.117421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/08/2023] [Accepted: 07/19/2023] [Indexed: 08/15/2023]
Abstract
The development of SAR around substituted N-piperidinyl indole-based nociceptin opioid receptor (NOP) ligands led to the discovery of a novel series of 2-substituted N-piperidinyl indoles that provide both selective NOP full agonists and bifunctional NOP full agonists-μ opioid (MOP) receptor partial agonists. 2-substituted N-piperidinyl indoles have improved potency at the NOP receptor and are NOP full agonists, compared to our previously reported 3-substituted N-piperidinyl indoles that are selective NOP partial agonists. SAR in this series of 2-substituted N-piperidinyl indoles shows that 2-substitution versus 3-substitution on the indole moiety affects their intrinsic activity and opioid receptor selectivity. Molecular docking of these 2-substituted N-piperidinyl indoles in an active-state NOP homology model and MOP receptor structures provides a rationale for the differences observed in the binding, functional profiles and selectivity of 2-substituted versus 3-substituted N-piperidinyl indoles.
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Affiliation(s)
- Michael E Meyer
- Astraea Therapeutics, LLC, 320 Logue Ave, Suite 142, Mountain View, CA 94043, USA
| | - Arpit Doshi
- Astraea Therapeutics, LLC, 320 Logue Ave, Suite 142, Mountain View, CA 94043, USA
| | - Willma E Polgar
- Astraea Therapeutics, LLC, 320 Logue Ave, Suite 142, Mountain View, CA 94043, USA
| | - Nurulain T Zaveri
- Astraea Therapeutics, LLC, 320 Logue Ave, Suite 142, Mountain View, CA 94043, USA.
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Iqbal A, Hamid A, Ahmad SM, Lutfy K. The Role of Mu Opioid Receptors in High Fat Diet-Induced Reward and Potentiation of the Rewarding Effect of Oxycodone. Life (Basel) 2023; 13:life13030619. [PMID: 36983775 PMCID: PMC10055773 DOI: 10.3390/life13030619] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
Excessive high fat diet (HFD) consumption can induce food addiction, which is believed to involve the communication between the hypothalamus and mesolimbic dopaminergic neurons, originating in the ventral tegmental area (VTA) and projecting to the nucleus accumbens (NAc). These brain areas are densely populated with opioid receptors, raising the possibility that these receptors, and particularly mu opioid receptors (MORs), are involved in rewards elicited by palatable food. This study sought to investigate the involvement of MORs in HFD-induced reward and if there is any difference between male and female subjects in this response. We also assessed if exposure to HFD would alter the rewarding action of oxycodone, a relatively selective MOR agonist. The place conditioning paradigm was used as an animal model of reward to determine if short-time (STC, 2 h) or long-time (LTC, 16 h) conditioning with HFD induces reward or alters the rewarding action of oxycodone. Male and female C57BL/6J mice as well as MOR knockout and their wildtype littermates of both sexes were tested for basal place preference on day 1 and then conditioned with an HFD in one chamber and a regular chow diet (RCD) in another chamber for 2 h on alternate days. Three sets of STC were used, followed by a set of LTC. Each set of conditioning consisted of two conditioning with RCD and two conditioning with HFD. Mice were tested for place preference after each set of STC and again after LTC. Controls were conditioned with RCD in both conditioning chambers. Following the last place preference test, mice were treated with oxycodone and conditioned in the HFD-paired chamber and with saline in the RCD-paired chamber for one hour once a day to explore the possibility if the HFD could alter oxycodone reward. The result showed that HFD induced conditioned place preference (CPP) in male but not female subjects. However, oxycodone conditioning elicited reward in both male and female mice of the HFD group but not the control group, showing that prior conditioning with HFD potentiated the rewarding action of oxycodone. The latter response was mediated via MORs, as it was blunted in MOR knockout mice. Similarly, HFD-induced CPP was blunted in male MOR knockout mice, suggesting sexual dimorphism in this response.
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Attenuated G protein signaling and minimal receptor phosphorylation as a biochemical signature of low side-effect opioid analgesics. Sci Rep 2022; 12:7154. [PMID: 35504962 PMCID: PMC9065038 DOI: 10.1038/s41598-022-11189-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 04/01/2022] [Indexed: 12/20/2022] Open
Abstract
Multi-receptor targeting has been proposed as a promising strategy for the development of opioid analgesics with fewer side effects. Cebranopadol and AT-121 are prototypical bifunctional ligands targeting the nociceptin/orphanin FQ peptide receptor (NOP) and µ-opioid receptor (MOP) that elicit potent analgesia in humans and nonhuman primates, respectively. Cebranopadol was reported to produce typical MOP-related side effects such as respiratory depression and reward, whereas AT-121 appeared to be devoid of these liabilities. However, the molecular basis underlying different side effect profiles in opioid analgesics remains unknown. Here, we examine agonist-induced receptor phosphorylation and G protein signaling profiles of a series of chemically diverse mixed MOP/NOP agonists, including cebranopadol and AT-121. We found that these compounds produce strikingly different MOP phosphorylation profiles. Cebranopadol, AT-034 and AT-324 stimulated extensive MOP phosphorylation, whereas AT-201 induced selective phosphorylation at S375 only. AT-121, on the other hand, did not promote any detectable MOP phosphorylation. Conversely, none of these compounds was able to elicit strong NOP phosphorylation and low NOP receptor phosphorylation correlated with partial agonism in a GIRK-channel assay. Our results suggest a close correlation between MOP receptor phosphorylation and side effect profile. Thus, bifunctional MOP/NOP opioid ligands combining low efficacy G protein signaling at both NOP and MOP with no detectable receptor phosphorylation appear to be devoid of side-effects such as respiratory depression, abuse liability or tolerance development, as with AT-121.
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Toll L, Cippitelli A, Ozawa A. The NOP Receptor System in Neurological and Psychiatric Disorders: Discrepancies, Peculiarities and Clinical Progress in Developing Targeted Therapies. CNS Drugs 2021; 35:591-607. [PMID: 34057709 PMCID: PMC8279133 DOI: 10.1007/s40263-021-00821-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/28/2021] [Indexed: 02/01/2023]
Abstract
The nociceptin opioid peptide (NOP) receptor and its endogenous ligand nociceptin/orphanin FQ (N/OFQ) are the fourth members of the opioid receptor and opioid peptide families. Although they have considerable sequence homology to the other family members, they are not considered opioid per se because they do not have pharmacological profiles similar to the other family members. The number of NOP receptors in the brain is higher than the other family members, and NOP receptors can be found throughout the brain. Because of the widespread distribution of NOP receptors, N/OFQ and other peptide and small molecule agonists and antagonists have extensive CNS activities. Originally thought to be anti-opioid, NOP receptor agonists block some opioid activities, potentiate others, and modulate other activities not affected by traditional opiates. Because the effect of receptor activation can be dependent upon site of administration, state of the animal, and other variables, the study of NOP receptors has been fraught with contradictions and inconsistencies. In this article, the actions and controversies pertaining to NOP receptor activation and inhibition are discussed with respect to CNS disorders including pain (acute, chronic, and migraine), drug abuse, anxiety and depression. In addition, progress towards clinical use of NOP receptor-directed compounds is discussed.
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Affiliation(s)
- Lawrence Toll
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL, 33431, USA.
| | - Andrea Cippitelli
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL, 33431, USA
| | - Akihiko Ozawa
- Department of Biomedical Sciences, Charles E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL, 33431, USA
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Meyer ME, Doshi A, Yasuda D, Zaveri NT. Structure-Based SAR in the Design of Selective or Bifunctional Nociceptin (NOP) Receptor Agonists. AAPS JOURNAL 2021; 23:68. [PMID: 33974173 DOI: 10.1208/s12248-021-00589-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/28/2021] [Indexed: 11/30/2022]
Abstract
The nociceptin opioid receptor (NOP), the fourth member of the opioid receptor family, and its endogenous peptide ligand, nociceptin or orphanin FQ (N/OFQ), play a vital role in several central nervous system pathways regulating pain, reward, feeding, anxiety, motor control and learning/memory. Both selective NOP agonists as well as bifunctional agonists at the NOP and mu opioid receptor (MOP) have potential therapeutic applications in CNS disorders related to these processes. Using Surflex-Dock protocols, we conducted a computational structure-activity study of four scaffold classes of NOP ligands with varying NOP-MOP selectivity. By docking these compounds into the orthosteric binding sites within an active-state NOP homology model, and an active-state MOP crystal structure, the goal of this study was to use a structure-based drug design approach to modulate NOP affinity and NOP vs. MOP selectivity. We first docked four parent compounds (no side chain) to determine their binding interactions within the NOP and MOP binding pockets. Various polar sidechains were added to the heterocyclic A-pharmacophore to modulate NOP ligand affinity. The substitutions mainly contained a 1-2 carbon chain with a polar substituent such as an amine, alcohol, sulfamide, or guanidine. The SAR analysis is focused on the impact of structural changes in the sidechain, such as chain length, hydrogen bonding capability, and basic vs neutral functional groups on binding affinity and selectivity at both NOP and MOP receptors. This study highlights structural modifications that can be leveraged to rationally design both selective NOP and bifunctional NOP-MOP agonists with different ratios of functional efficacy.
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Affiliation(s)
- Michael E Meyer
- Astraea Therapeutics, LLC, 320 Logue Avenue, Mountain View, California, 94043, USA
| | - Arpit Doshi
- Astraea Therapeutics, LLC, 320 Logue Avenue, Mountain View, California, 94043, USA
| | - Dennis Yasuda
- Astraea Therapeutics, LLC, 320 Logue Avenue, Mountain View, California, 94043, USA
| | - Nurulain T Zaveri
- Astraea Therapeutics, LLC, 320 Logue Avenue, Mountain View, California, 94043, USA.
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Lu JJ, Polgar WE, Mann A, Dasgupta P, Schulz S, Zaveri NT. Differential In Vitro Pharmacological Profiles of Structurally Diverse Nociceptin Receptor Agonists in Activating G Protein and Beta-Arrestin Signaling at the Human Nociceptin Opioid Receptor. Mol Pharmacol 2021; 100:7-18. [PMID: 33958480 DOI: 10.1124/molpharm.120.000076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 03/26/2021] [Indexed: 11/22/2022] Open
Abstract
Agonists at the nociceptin opioid peptide receptor (NOP) are under investigation as therapeutics for nonaddicting analgesia, opioid use disorder, Parkinson's disease, and other indications. NOP full and partial agonists have both been of interest, particularly since NOP partial agonists show a reduced propensity for behavioral disruption than NOP full agonists. Here, we investigated the in vitro pharmacological properties of chemically diverse NOP receptor agonists in assays measuring functional activation of the NOP receptor such as guanosine 5'-O-[gamma-thio]triphosphate (GTPγS) binding, cAMP inhibition, G protein-coupled inwardly rectifying potassium (GIRK) channel activation, phosphorylation, β-arrestin recruitment and receptor internalization. When normalized to the efficacy of the natural agonist nociceptin/orphanin FQ (N/OFQ), we found that different functional assays that measure intrinsic activity produce inconsistent levels of agonist efficacy, particularly for ligands that were partial agonists. Agonist efficacy obtained in the GTPγS assay tended to be lower than that in the cAMP and GIRK assays. These structurally diverse NOP agonists also showed differential receptor phosphorylation profiles at the phosphosites we examined and induced varying levels of receptor internalization. Interestingly, although the rank order for β-arrestin recruitment by these NOP agonists was consistent with their ability to induce receptor internalization, their phosphorylation signatures at the time point we investigated were not indicative of the levels of β-arrestin recruitment or internalization induced by these agonists. It is possible that other phosphorylation sites, yet to be identified, drive the recruitment of NOP receptor ensembles and subsequent receptor trafficking by some nonpeptide NOP agonists. These findings potentially help understand NOP agonist pharmacology in the context of ligand-activated receptor trafficking. SIGNIFICANCE STATEMENT: Chemically diverse agonist ligands at the nociceptin opioid receptor G protein-coupled receptor showed differential efficacy for activating downstream events after receptor binding, in a suite of functional assays measuring guanosine 5'-O-[gamma-thio]triphosphate binding, cAMP inhibition, G protein-coupled inwardly rectifying protein channel activation, β-arrestin recruitment, receptor internalization and receptor phosphorylation. These analyses provide a context for understanding nociceptin opioid peptide receptor (NOP) agonist pharmacology driven by ligand-induced differential NOP receptor signaling.
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Affiliation(s)
- James J Lu
- Astraea Therapeutics, Mountain View, California (J.J.L., W.E.P., N.T.Z.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (A.M., P.D., S.S.)
| | - Willma E Polgar
- Astraea Therapeutics, Mountain View, California (J.J.L., W.E.P., N.T.Z.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (A.M., P.D., S.S.)
| | - Anika Mann
- Astraea Therapeutics, Mountain View, California (J.J.L., W.E.P., N.T.Z.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (A.M., P.D., S.S.)
| | - Pooja Dasgupta
- Astraea Therapeutics, Mountain View, California (J.J.L., W.E.P., N.T.Z.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (A.M., P.D., S.S.)
| | - Stefan Schulz
- Astraea Therapeutics, Mountain View, California (J.J.L., W.E.P., N.T.Z.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (A.M., P.D., S.S.)
| | - Nurulain T Zaveri
- Astraea Therapeutics, Mountain View, California (J.J.L., W.E.P., N.T.Z.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (A.M., P.D., S.S.)
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Cippitelli A, Barnes M, Zaveri NT, Toll L. Potent and selective NOP receptor activation reduces cocaine self-administration in rats by lowering hedonic set point. Addict Biol 2020; 25:e12844. [PMID: 31709687 DOI: 10.1111/adb.12844] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/29/2019] [Accepted: 09/30/2019] [Indexed: 12/16/2022]
Abstract
Developing new medications for the treatment of cocaine dependence continues to be a research priority. Compelling evidence indicates that mixed opioid receptor agonists, particularly bifunctional compounds that target nociceptin/orphanin FQ peptide (NOP) and mu opioid receptors, may be useful for the treatment of cocaine addiction. Here, we verify that potent and selective pharmacological activation of NOP receptors is sufficient to reduce relevant facets of cocaine addiction in animal models. Accordingly, we determined whether systemic injections of the small molecule AT-312 (0, 1, 3 mg/kg) could reduce operant cocaine self-administration, motivation for cocaine, and vulnerability to cocaine relapse in rats. Results indicate that a potent and selective NOP receptor agonist was equally efficacious in reducing the number of cocaine infusions in short (1-hour), as well as long (6-hour) access sessions. When tested on an economic-demand reinforcement schedule, AT-312 reduced Q0 , the parameter that describes the amount of drug consumed at zero price, while leaving the parameter α, a measure of motivation for drug consumption, unaltered. Furthermore, AT-312 successfully reduced conditioned reinstatement of cocaine seeking. In contrast, the NOP receptor agonist did not modify food self-administration. Blockade of the NOP receptor with the antagonist SB-612111 prevented the effect of AT-312 in decreasing cocaine-reinforced responding under a 2-hour fixed ratio 1 schedule, suggesting a NOP receptor-mediated mechanism. This work demonstrates that potent and selective activation of NOP receptors is sufficient to decrease cocaine taking and seeking behaviors in rats.
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Affiliation(s)
- Andrea Cippitelli
- Biomedical Science Department Charles E. Schmidt College of Medicine Florida Atlantic University Boca Raton FL United States
| | - Megan Barnes
- Biomedical Science Department Charles E. Schmidt College of Medicine Florida Atlantic University Boca Raton FL United States
| | | | - Lawrence Toll
- Biomedical Science Department Charles E. Schmidt College of Medicine Florida Atlantic University Boca Raton FL United States
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Rapid assessment of G protein signaling of four opioid receptors using a real-time fluorescence-based membrane potential assay. Eur J Pharmacol 2020; 890:173640. [PMID: 33045198 DOI: 10.1016/j.ejphar.2020.173640] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 10/02/2020] [Accepted: 10/08/2020] [Indexed: 11/24/2022]
Abstract
Opioids are the most powerful analgesics used clinically; however, severe side effects limit their long-term use. Various concepts involving biased intracellular signaling, partial agonism or multi-receptor targeting have been proposed to identify novel opioids with increased analgesic efficacy but reduced side effects. The search for such 'better opioids' implies screening of huge compound libraries and requires highly reliable, easy to perform and high throughput screening (HTS) assays. Here, we utilize an established membrane potential assay to monitor activation of G protein-coupled inwardly rectifying potassium (GIRK) channels, one of the main effectors of opioid receptor signaling, as readout to determine pharmacological profiles of opioids in a non-invasive manner. Specifically, in this study, we optimize assay conditions and extend the application of this assay to screen all four members of the opioid receptor family, stably expressed in AtT-20 and HEK293 cells. This ultra-sensitive system yielded EC50 values in the nano-molar range. We further validate this system for screening cells stably co-expressing two opioid receptors, which could be a valuable tool for investigating bi-functional ligands and studying interactions between receptors. Additionally, we demonstrate the utility of this assay to study antagonists as well as ligands with varying efficacies. Our results suggest that this assay could easily be up-scaled to HTS assay in order to efficiently study receptor activation and screen for novel opioids.
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Abstract
This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY, 11367, United States.
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12
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Borruto AM, Fotio Y, Stopponi S, Brunori G, Petrella M, Caputi FF, Romualdi P, Candeletti S, Narendran R, Rorick-Kehn LM, Ubaldi M, Weiss F, Ciccocioppo R. NOP receptor antagonism reduces alcohol drinking in male and female rats through mechanisms involving the central amygdala and ventral tegmental area. Br J Pharmacol 2020; 177:1525-1537. [PMID: 31713848 DOI: 10.1111/bph.14915] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 10/14/2019] [Accepted: 10/17/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE Nociceptin/orphanin FQ (N/OFQ) peptide and its cognate receptor (NOP) are widely expressed in mesolimbic brain regions where they play an important role in modulating reward and motivation. Early evidence suggested that NOP receptor activation attenuates the rewarding effects of drugs of abuse, including alcohol. However, emerging data indicate that NOP receptor blockade also effectively attenuates alcohol drinking and relapse. To advance our understanding of the role of the N/OFQ-NOP receptor system in alcohol abuse, we examined the effect of NOP receptor blockade on voluntary alcohol drinking at the neurocircuitry level. EXPERIMENTAL APPROACH Using male and female genetically selected alcohol-preferring Marchigian Sardinian (msP) rats, we initially evaluated the effects of the selective NOP receptor antagonist LY2817412 (3, 10, and 30 mg·kg-1 , p.o.) on alcohol consumption in a two-bottle free-choice paradigm. We then microinjected LY2817412 (3 and 6 μg·μl-1 per rat) in the central nucleus of the amygdala (CeA), ventral tegmental area (VTA), and nucleus accumbens (NAc). KEY RESULTS Peripheral LY2817412 administration dose-dependently and selectively reduced voluntary alcohol intake in male and female msP rats. Central injections of LY2817412 markedly attenuated voluntary alcohol intake in both sexes following administration in the CeA and VTA but not in the NAc. CONCLUSION AND IMPLICATIONS The present results revealed that the CeA and VTA are neuroanatomical substrates that mediate the effects of NOP receptor antagonism on alcohol consumption. Overall, our findings support the potential of NOP receptor antagonism as a treatment strategy to attenuate alcohol use and addiction.
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Affiliation(s)
| | - Yannick Fotio
- School of Pharmacy, Pharmacology Unit, University of Camerino, Italy
| | - Serena Stopponi
- School of Pharmacy, Pharmacology Unit, University of Camerino, Italy
| | - Gloria Brunori
- School of Pharmacy, Pharmacology Unit, University of Camerino, Italy.,Department of Biomedical Science, Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
| | - Michele Petrella
- School of Pharmacy, Pharmacology Unit, University of Camerino, Italy
| | - Francesca Felicia Caputi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Sanzio Candeletti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Rajesh Narendran
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Linda M Rorick-Kehn
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, Indiana, USA
| | - Massimo Ubaldi
- School of Pharmacy, Pharmacology Unit, University of Camerino, Italy
| | - Friedbert Weiss
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California, USA
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13
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Neasta J, Darcq E, Jeanblanc J, Carnicella S, Ben Hamida S. GPCR and Alcohol-Related Behaviors in Genetically Modified Mice. Neurotherapeutics 2020; 17:17-42. [PMID: 31919661 PMCID: PMC7007453 DOI: 10.1007/s13311-019-00828-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest class of cell surface signaling receptors and regulate major neurobiological processes. Accordingly, GPCRs represent primary targets for the treatment of brain disorders. Several human genetic polymorphisms affecting GPCRs have been associated to different components of alcohol use disorder (AUD). Moreover, GPCRs have been reported to contribute to several features of alcohol-related behaviors in animal models. Besides traditional pharmacological tools, genetic-based approaches mostly aimed at deleting GPCR genes provided substantial information on how key GPCRs drive alcohol-related behaviors. In this review, we summarize the alcohol phenotypes that ensue from genetic manipulation, in particular gene deletion, of key GPCRs in rodents. We focused on GPCRs that belong to fundamental neuronal systems that have been shown as potential targets for the development of AUD treatment. Data are reviewed with particular emphasis on alcohol reward, seeking, and consumption which are behaviors that capture essential aspects of AUD. Literature survey indicates that in most cases, there is still a gap in defining the intracellular transducers and the functional crosstalk of GPCRs as well as the neuronal populations in which their signaling regulates alcohol actions. Further, the implication of only a few orphan GPCRs has been so far investigated in animal models. Combining advanced pharmacological technologies with more specific genetically modified animals and behavioral preclinical models is likely necessary to deepen our understanding in how GPCR signaling contributes to AUD and for drug discovery.
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Affiliation(s)
- Jérémie Neasta
- Laboratoire de Pharmacologie, Faculté de Pharmacie, University of Montpellier, 34093, Montpellier, France
| | - Emmanuel Darcq
- Douglas Hospital Research Center, Department of Psychiatry, McGill University, 6875 Boulevard LaSalle, Montreal, Quebec, H4H 1R3, Canada
| | - Jérôme Jeanblanc
- Research Group on Alcohol and Pharmacodependences-INSERM U1247, University of Picardie Jules Verne, 80025, Amiens, France
| | - Sebastien Carnicella
- INSERM U1216, Grenoble Institut des Neurosciences (GIN), University of Grenoble Alpes, 38000, Grenoble, France
| | - Sami Ben Hamida
- Douglas Hospital Research Center, Department of Psychiatry, McGill University, 6875 Boulevard LaSalle, Montreal, Quebec, H4H 1R3, Canada.
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14
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Brunori G, Weger M, Schoch J, Targowska-Duda K, Barnes M, Borruto AM, Rorick-Kehn LM, Zaveri NT, Pintar JE, Ciccocioppo R, Toll L, Cippitelli A. NOP Receptor Antagonists Decrease Alcohol Drinking in the Dark in C57BL/6J Mice. Alcohol Clin Exp Res 2019; 43:2167-2178. [PMID: 31386211 DOI: 10.1111/acer.14165] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 07/25/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND The nociceptin/orphanin FQ opioid peptide (NOP) receptor and its endogenous ligand N/OFQ have been implicated in the regulation of drug and alcohol use disorders (AUD). In particular, evidence demonstrated that NOP receptor activation blocks reinforcing and motivating effects of alcohol across a range of behavioral measures, including alcohol intake, conditioned place preference, and vulnerability to relapse. METHODS Here, we show the effects of pharmacological activation and inhibition of NOP receptors on binge-like alcohol consumption, as measured by the "drinking in the dark" (DID) model in C57BL/6J mice. RESULTS We found that 2 potent and selective NOP agonists AT-202 (0, 0.3, 1, 3 mg/kg) and AT-312 (0, 0.3, 1 mg/kg) did not affect binge alcohol drinking at doses that do not affect locomotor activity. AT-202 also failed to alter DID behavior when administered to mice previously exposed to chronic alcohol treatment with an alcohol-containing liquid diet. Conversely, treatment with either the high affinity NOP receptor antagonist SB-612111 (0, 3, 10, 30 mg/kg) or the selective antagonist LY2817412 (0, 3, 10, 30 mg/kg) decreased binge drinking. SB-612111 was effective at all doses examined, and LY2817412 was effective at 30 mg/kg. Consistently, NOP receptor knockout mice consumed less alcohol compared to wild type. SB-612111 reduced DID and increased sucrose consumption at doses that do not appear to affect locomotor activity. However, the high dose of SB-612111 (30 mg/kg) reduced alcohol intake but failed to inhibit preference in a 2-bottle choice DID model that can assess moderate alcohol intake. CONCLUSIONS The present results suggest that NOP receptor inhibition rather than activation may represent a valuable approach for treatment of AUD characterized by excessive alcohol consumption such as binge drinking.
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Affiliation(s)
- Gloria Brunori
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida.,Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida.,Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Michelle Weger
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida
| | - Jennifer Schoch
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida.,Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida
| | - Katarzyna Targowska-Duda
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida.,Department of Biopharmacy, Medical University of Lublin, Lublin, Poland
| | - Megan Barnes
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida
| | - Anna Maria Borruto
- Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | | | | | - John E Pintar
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey
| | - Roberto Ciccocioppo
- Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Lawrence Toll
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida.,Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida
| | - Andrea Cippitelli
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida.,Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida
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15
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Abstract
The development of nonpeptide systemically active small-molecule NOP-targeted ligands has contributed tremendously to validating the NOP receptor as a promising target for therapeutics. Although a NOP-targeted compound is not yet approved for clinical use, a few NOP ligands are in clinical trials for various indications. Both successful and failed human clinical trials with NOP ligands provide opportunities for rational development of new and improved NOP-targeted compounds. A few years after the discovery of the NOP receptor in 1994, and its de-orphanization upon discovery of the endogenous peptide nociceptin/orphanin FQ (N/OFQ) in 1995, there was a significant effort in the pharmaceutical industry to discover nonpeptide NOP ligands from hits obtained from high-throughput screening campaigns of compound libraries. Depending on the therapeutic indication to be pursued, NOP agonists and antagonists were discovered, and some were optimized as clinical candidates. Advances such as G protein-coupled receptor (GPCR) structure elucidation, functional selectivity in ligand-driven GPCR activation, and multi-targeted ligands provide new scope for the rational design of novel NOP ligands fine-tuned for successful clinical translation. This article reviews the field of nonpeptide NOP ligand drug design in the context of these exciting developments and highlights new optimized nonpeptide NOP ligands possessing interesting functional profiles, which are particularly attractive for several unmet clinical applications involving NOP receptor pharmacomodulation.
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16
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Ciccocioppo R, Borruto AM, Domi A, Teshima K, Cannella N, Weiss F. NOP-Related Mechanisms in Substance Use Disorders. Handb Exp Pharmacol 2019; 254:187-212. [PMID: 30968214 PMCID: PMC6641545 DOI: 10.1007/164_2019_209] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
Nociceptin/orphanin FQ (N/OFQ) is a 17 amino acid peptide that was deorphanized in 1995 and has been widely studied since. The role of the N/OFQ system in drug abuse has attracted researchers' attention since its initial discovery. The first two scientific papers describing the effect of intracranial injection of N/OFQ appeared 20 years ago and reported efficacy of the peptide in attenuating alcohol intake, whereas heroin self-administration was insensitive. Since then more than 100 scientific articles investigating the role of the N/OFQ and N/OFQ receptor (NOP) system in drug abuse have been published. The present article provides an historical overview of the advances in the field with focus on three major elements. First, the most robust data supportive of the efficacy of NOP agonists in treating drug abuse come from studies in the field of alcohol research, followed by psychostimulant and opioid research. In contrast, activation of NOP appears to facilitate nicotine consumption. Second, emerging data challenge the assumption that activation of NOP is the most appropriate strategy to attenuate consumption of substances of abuse. This assumption is based first on the observation that animals carrying an overexpression of NOP system components are more prone to consume substances of abuse, whereas NOP knockout rats are less motivated to self-administer heroin, alcohol, and cocaine. Third, administration of NOP antagonists also reduces alcohol consumption. In addition, NOP blockade reduces nicotine self-administration. Hypothetical mechanisms explaining this apparent paradox are discussed. Finally, we focus on the possibility that co-activation of NOP and mu opioid (MOP) receptors is an alternative strategy, readily testable in the clinic, to reduce the consumption of psychostimulants, opiates, and, possibly, alcohol.
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Affiliation(s)
- Roberto Ciccocioppo
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy.
| | - Anna Maria Borruto
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Ana Domi
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Koji Teshima
- Research Unit/Neuroscience, Innovative Research Division, Mitsubishi Tanabe Pharma Corporation, Osaka, Japan
| | - Nazzareno Cannella
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Friedbert Weiss
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
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17
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Zaveri NT, Marquez PV, Meyer ME, Hamid A, Lutfy K. The Nociceptin Receptor (NOP) Agonist AT-312 Blocks Acquisition of Morphine- and Cocaine-Induced Conditioned Place Preference in Mice. Front Psychiatry 2018; 9:638. [PMID: 30555362 PMCID: PMC6281746 DOI: 10.3389/fpsyt.2018.00638] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/12/2018] [Indexed: 11/22/2022] Open
Abstract
Treatment of drug addiction remains an unmet medical need due to the dearth of approved pharmacotherapies. There are no approved treatments for cocaine addiction, whereas the current opioid crisis has revealed the stark reality of the limited options to treat prescription and illicit opioid abuse. Preclinical studies in rodents and nonhuman primates have shown that orphanin FQ/nociceptin (N/OFQ), the endogenous ligand for the nociceptin opioid receptor (NOP) reduces the rewarding effects of several abused substances, including opioids, psychostimulants and alcohol. A few nonpeptide small-molecule NOP agonists have also shown efficacy in attenuating the rewarding effects of various abused drugs. We previously demonstrated that a high affinity small-molecule NOP agonist AT-312 selectively reduced the rewarding effects of ethanol in the conditioned place preference paradigm in mice. In the present study, we examined if AT-312 (3 mg/kg, i.p. or s.c. respectively), would alter the rewarding action of morphine (7.5 mg/kg, s.c.) or cocaine (15 mg/kg, i.p.). The effect of AT-312 on morphine- and cocaine-induced motor stimulation was also assessed on the conditioning days. The role of the NOP receptor in the effects of AT-312 was further confirmed by conducting the place conditioning experiments in NOP knockout mice and compared to their wild-type controls. Our results showed that AT-312 significantly reduced the acquisition of morphine and cocaine CPP in wild-type mice but not in mice lacking NOP receptors. AT-312 also suppressed morphine-induced and completely abolished cocaine-induced motor stimulation in NOP wild-type mice, but not in NOP knockout mice. These results show that small-molecule NOP receptor agonists have promising efficacy for attenuating the rewarding effects of morphine and cocaine, and may have potential as pharmacotherapy for opioid and psychostimulant addiction or for treating polydrug addiction.
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Affiliation(s)
- Nurulain T Zaveri
- Astraea Therapeutics, LLC, Mountain View, California, CA, United States
| | - Paul V Marquez
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, United States
| | - Michael E Meyer
- Astraea Therapeutics, LLC, Mountain View, California, CA, United States
| | - Abdul Hamid
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, United States
| | - Kabirullah Lutfy
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, United States
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