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Molla HM, Miguelez Fernández AMM, Tseng KY. Late-adolescent onset of prefrontal endocannabinoid control of hippocampal and amygdalar inputs and its impact on trace-fear conditioning behavior. Neuropsychopharmacology 2024:10.1038/s41386-024-01844-z. [PMID: 38467844 DOI: 10.1038/s41386-024-01844-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/13/2024]
Abstract
Prefrontal cortex (PFC) maturation during adolescence is characterized by structural and functional changes, which involve the remodeling of GABA and glutamatergic synapses, as well as changes in the endocannabinoid system. Yet, the way PFC endocannabinoid signaling interacts with local GABA and glutamatergic function to impact its processing of afferent transmission during the adolescent transition to adulthood remains unknown. Here we combined PFC local field potential recordings with local manipulations of 2-AG and anandamide levels to assess how PFC endocannabinoid signaling is recruited to modulate ventral hippocampal and basolateral amygdalar inputs in vivo in adolescent and adult male rats. We found that the PFC endocannabinoid signaling does not fully emerge until late-adolescence/young adulthood. Once present, both 2-AG and anandamide can be recruited in the PFC to limit the impact of hippocampal drive through a CB1R-mediated mechanism whereas basolateral amygdalar inputs are only inhibited by 2-AG. Similarly, the behavioral effects of increasing 2-AG and anandamide in the PFC do not emerge until late-adolescence/young adulthood. Using a trace fear conditioning paradigm, we found that elevating PFC 2-AG levels preferentially reduced freezing behavior during acquisition without affecting its extinction. In contrast, increasing anandamide levels in the PFC selectively disrupted the extinction of trace fear memory without affecting its acquisition. Collectively, these results indicate a protracted recruitment of PFC endocannabinoid signaling, which becomes online in late adolescence/young adulthood as revealed by its impact on hippocampal and amygdalar-evoked local field potential responses and trace fear memory behavior.
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Affiliation(s)
- Hanna M Molla
- Department of Anatomy and Cell Biology, University of Illinois Chicago - College of Medicine, Chicago, IL, 60612, USA
| | - Anabel M M Miguelez Fernández
- Department of Anatomy and Cell Biology, University of Illinois Chicago - College of Medicine, Chicago, IL, 60612, USA
| | - Kuei Y Tseng
- Department of Anatomy and Cell Biology, University of Illinois Chicago - College of Medicine, Chicago, IL, 60612, USA.
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Richardson BJ, Hamilton J, Roeder N, Thanos KZ, Marion M, Thanos PK. Fatty acid-binding protein 5 differentially impacts dopamine signaling independent of sex and environment. ADDICTION NEUROSCIENCE 2023; 8:100118. [PMID: 37664218 PMCID: PMC10470066 DOI: 10.1016/j.addicn.2023.100118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Epidermal/brain fatty acid-binding protein 5 (FABP5) plays an integral role in the intracellular trafficking of bioactive lipids/endocannabinoids and the subsequent initiation of cellular cascades affecting cannabinoid and dopamine (DA) systems. Social isolation (SI) and environmental enrichment (EE) during adolescence have been shown to impact DA signaling, and, specifically, DA transporter (DAT) and receptor levels of DA type 1 (D1) and 2 (D2); however, the relationship between FABP5, environment and DA signaling remains unclear. The present study quantified DAT and DA receptor levels in male/female FABP5-/- and FABP5+/+ mice raised in either SI or EE. Results showed that FABP5-/- mice had 6.09-8.81% greater D1 levels in striatal sub-regions of the caudal brain, independent of sex or environment. D1 levels were 8.03% greater only in the olfactory tubercle of enrichment-reared animals. In summary, these results supported that FABP5 plays an important function in regulating striatal DA signaling, and this may have important implications as a target with therapeutic potential for various psychiatric disorders.
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Affiliation(s)
- Brittany J. Richardson
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, University at Buffalo, 1021 Main Street, Buffalo, NY 14203-1016, USA
| | - John Hamilton
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, University at Buffalo, 1021 Main Street, Buffalo, NY 14203-1016, USA
- Department of Psychology, University at Buffalo, Buffalo, NY, USA
| | - Nicole Roeder
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, University at Buffalo, 1021 Main Street, Buffalo, NY 14203-1016, USA
- Department of Psychology, University at Buffalo, Buffalo, NY, USA
| | - Kyriaki Z. Thanos
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, University at Buffalo, 1021 Main Street, Buffalo, NY 14203-1016, USA
| | - Matthew Marion
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, University at Buffalo, 1021 Main Street, Buffalo, NY 14203-1016, USA
| | - Panayotis K. Thanos
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, University at Buffalo, 1021 Main Street, Buffalo, NY 14203-1016, USA
- Department of Psychology, University at Buffalo, Buffalo, NY, USA
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3
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Mikaeili H, Habib AM, Yeung CWL, Santana-Varela S, Luiz AP, Panteleeva K, Zuberi S, Athanasiou-Fragkouli A, Houlden H, Wood JN, Okorokov AL, Cox JJ. Molecular basis of FAAH-OUT-associated human pain insensitivity. Brain 2023; 146:3851-3865. [PMID: 37222214 PMCID: PMC10473560 DOI: 10.1093/brain/awad098] [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: 11/03/2022] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 05/25/2023] Open
Abstract
Chronic pain affects millions of people worldwide and new treatments are needed urgently. One way to identify novel analgesic strategies is to understand the biological dysfunctions that lead to human inherited pain insensitivity disorders. Here we report how the recently discovered brain and dorsal root ganglia-expressed FAAH-OUT long non-coding RNA (lncRNA) gene, which was found from studying a pain-insensitive patient with reduced anxiety and fast wound healing, regulates the adjacent key endocannabinoid system gene FAAH, which encodes the anandamide-degrading fatty acid amide hydrolase enzyme. We demonstrate that the disruption in FAAH-OUT lncRNA transcription leads to DNMT1-dependent DNA methylation within the FAAH promoter. In addition, FAAH-OUT contains a conserved regulatory element, FAAH-AMP, that acts as an enhancer for FAAH expression. Furthermore, using transcriptomic analyses in patient-derived cells we have uncovered a network of genes that are dysregulated from disruption of the FAAH-FAAH-OUT axis, thus providing a coherent mechanistic basis to understand the human phenotype observed. Given that FAAH is a potential target for the treatment of pain, anxiety, depression and other neurological disorders, this new understanding of the regulatory role of the FAAH-OUT gene provides a platform for the development of future gene and small molecule therapies.
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Affiliation(s)
- Hajar Mikaeili
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Abdella M Habib
- College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Charlix Wai-Lok Yeung
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Sonia Santana-Varela
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Ana P Luiz
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Kseniia Panteleeva
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Sana Zuberi
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | | | - Henry Houlden
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - John N Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Andrei L Okorokov
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - James J Cox
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
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Oddi S, Fiorenza MT, Maccarrone M. Endocannabinoid signaling in adult hippocampal neurogenesis: A mechanistic and integrated perspective. Prog Lipid Res 2023; 91:101239. [PMID: 37385352 DOI: 10.1016/j.plipres.2023.101239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 06/01/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
Dentate gyrus of the hippocampus continuously gives rise to new neurons, namely, adult-born granule cells, which contribute to conferring plasticity to the mature brain throughout life. Within this neurogenic region, the fate and behavior of neural stem cells (NSCs) and their progeny result from a complex balance and integration of a variety of cell-autonomous and cell-to-cell-interaction signals and underlying pathways. Among these structurally and functionally diverse signals, there are endocannabinoids (eCBs), the main brain retrograde messengers. These pleiotropic bioactive lipids can directly and/or indirectly influence adult hippocampal neurogenesis (AHN) by modulating, both positively and negatively, multiple molecular and cellular processes in the hippocampal niche, depending on the cell type or stage of differentiation. Firstly, eCBs act directly as cell-intrinsic factors, cell-autonomously produced by NSCs following their stimulation. Secondly, in many, if not all, niche-associated cells, including some local neuronal and nonneuronal elements, the eCB system indirectly modulates the neurogenesis, linking neuronal and glial activity to regulating distinct stages of AHN. Herein, we discuss the crosstalk of the eCB system with other neurogenesis-relevant signal pathways and speculate how the hippocampus-dependent neurobehavioral effects elicited by (endo)cannabinergic medications are interpretable in light of the key regulatory role that eCBs play on AHN.
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Affiliation(s)
- Sergio Oddi
- Department of Veterinary Medicine, University of Teramo, Via R. Balzarini 1, 64100 Teramo, Italy; European Center for Brain Research/IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 64, 00143 Rome, Italy.
| | - Maria Teresa Fiorenza
- European Center for Brain Research/IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 64, 00143 Rome, Italy; Department of Psychology, Division of Neuroscience and "Daniel Bovet" Neurobiology Research Center, Sapienza University of Rome, Via dei Sardi 70, 00185 Rome, Italy
| | - Mauro Maccarrone
- European Center for Brain Research/IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 64, 00143 Rome, Italy; Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio Snc, 67100 L'Aquila, Italy
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Balsevich G, Petrie GN, Heinz DE, Singh A, Aukema RJ, Hunker AC, Vecchiarelli HA, Yau H, Sticht M, Thompson RJ, Lee FS, Zweifel LS, Chelikani PK, Gassen NC, Hill MN. A genetic variant of fatty acid amide hydrolase (FAAH) exacerbates hormone-mediated orexigenic feeding in mice. eLife 2023; 12:e81919. [PMID: 37039453 PMCID: PMC10159625 DOI: 10.7554/elife.81919] [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: 07/15/2022] [Accepted: 04/06/2023] [Indexed: 04/12/2023] Open
Abstract
Fatty acid amide hydrolase (FAAH) degrades the endocannabinoid anandamide. A polymorphism in FAAH (FAAH C385A) reduces FAAH expression, increases anandamide levels, and increases the risk of obesity. Nevertheless, some studies have found no association between FAAH C385A and obesity. We investigated whether the environmental context governs the impact of FAAH C385A on metabolic outcomes. Using a C385A knock-in mouse model, we found that FAAH A/A mice are more susceptible to glucocorticoid-induced hyperphagia, weight gain, and activation of hypothalamic AMP-activated protein kinase (AMPK). AMPK inhibition occluded the amplified hyperphagic response to glucocorticoids in FAAH A/A mice. FAAH knockdown exclusively in agouti-related protein (AgRP) neurons mimicked the exaggerated feeding response of FAAH A/A mice to glucocorticoids. FAAH A/A mice likewise presented exaggerated orexigenic responses to ghrelin, while FAAH knockdown in AgRP neurons blunted leptin anorectic responses. Together, the FAAH A/A genotype amplifies orexigenic responses and decreases anorexigenic responses, providing a putative mechanism explaining the diverging human findings.
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Affiliation(s)
| | - Gavin N Petrie
- Hotchkiss Brain Institute, University of CalgaryCalgaryCanada
| | - Daniel E Heinz
- Neurohomeostasis Research Group, Department of Psychiatry and Psychotherapy, University Hospital BonnBonnGermany
| | - Arashdeep Singh
- Monell Chemical Senses Center and Department of Neuroscience, University of PennsylvaniaPhiladelphiaUnited States
| | - Robert J Aukema
- Hotchkiss Brain Institute, University of CalgaryCalgaryCanada
| | - Avery C Hunker
- Department of Psychiatry and Behavioral Sciences, University of WashingtonSeattleUnited States
| | | | - Hiulan Yau
- Hotchkiss Brain Institute, University of CalgaryCalgaryCanada
| | - Martin Sticht
- Hotchkiss Brain Institute, University of CalgaryCalgaryCanada
| | | | - Francis S Lee
- Weill Cornell Medical College, Cornell UniversityNew YorkUnited States
| | - Larry S Zweifel
- Department of Psychiatry and Behavioral Sciences, University of WashingtonSeattleUnited States
| | | | - Nils C Gassen
- Neurohomeostasis Research Group, Department of Psychiatry and Psychotherapy, University Hospital BonnBonnGermany
| | - Matthew N Hill
- Hotchkiss Brain Institute, University of CalgaryCalgaryCanada
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Roberts CJ, Hopp FA, Hogan QH, Dean C. Anandamide in the dorsal periaqueductal gray inhibits sensory input without a correlation to sympathoexcitation. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2022; 12:100104. [PMID: 36531614 PMCID: PMC9755024 DOI: 10.1016/j.ynpai.2022.100104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/09/2022] [Accepted: 09/15/2022] [Indexed: 01/11/2023]
Abstract
There is growing literature supporting cannabinoids as a potential therapeutic for pain conditions. The development of chronic pain has been associated with reduced concentrations of the endogenous cannabinoid anandamide (AEA) in the midbrain dorsal periaqueductal gray (dPAG), and microinjections of synthetic cannabinoids into the dPAG are antinociceptive. Therefore, the goal of this study was to examine the role of the dPAG in cannabinoid-mediated sensory inhibition. Given that cannabinoids in the dPAG also elicit sympathoexcitation, a secondary goal was to assess coordination between sympathetic and antinociceptive responses. AEA was microinjected into the dPAG while recording single unit activity of wide dynamic range (WDR) dorsal horn neurons (DHNs) evoked by high intensity mechanical stimulation of the hindpaw, concurrently with renal sympathetic nerve activity (RSNA), in anesthetized male rats. AEA microinjected into the dPAG decreased evoked DHN activity (n = 24 units), for half of which AEA also elicited sympathoexcitation. AEA actions were mediated by cannabinoid 1 receptors as confirmed by local pretreatment with the cannabinoid receptor antagonist AM281. dPAG microinjection of the synaptic excitant DL-homocysteic acid (DLH) also decreased evoked DHN activity (n = 27 units), but in all cases this was accompanied by sympathoexcitation. Thus, sensory inhibition elicited from the dPAG is not exclusively linked with sympathoexcitation, suggesting discrete neuronal circuits. The rostrocaudal location of sites may affect evoked responses as AEA produced sensory inhibition without sympathetic effects at 86 % of caudal compared to 25 % of rostral sites, supporting anatomically distinct neurocircuits. These data indicate that spatially selective manipulation of cannabinoid signaling could provide analgesia without potentially harmful autonomic activation.
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Key Words
- AEA, N-arachidonylethanolamine, anandamide
- Antinociception
- CB1R, cannabinoid type one receptor
- CV, cardiovascular
- Cannabinoid
- DHN, dorsal horn neuron
- DLH, DL-homocysteic acid
- Dorsal horn
- FAAH, fatty acid amide hydrolase
- GPCR, G protein-coupled receptor
- IML, intermediolateral cell column
- MAP, mean arterial pressure
- NTS, nucleus tractus solitarius
- PAG, periaqueductal gray
- PPAR, peroxisome proliferator activated receptor
- RSNA, renal sympathetic nerve activity
- RVLM, rostral ventrolateral medulla
- RVMM, rostral ventromedial medulla
- Rat
- SIA, stress-induced analgesia
- SNS, sympathetic nervous system
- Sympathetic nervous system
- TRPV1, transient receptor potential vanilloid type 1
- WDR, wide dynamic range
- dPAG, dorsal periaqueductal gray
- vPAG, ventral periaqueductal gray
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Affiliation(s)
- Christopher J. Roberts
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA,Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA
| | - Francis A. Hopp
- Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA
| | - Quinn H. Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA,Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA
| | - Caron Dean
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA,Department of Anesthesiology, Zablocki Veterans Affairs Medical Center, Milwaukee, WI 53295, USA,Corresponding author at: Department of Anesthesiology, Research Service 151, Zablocki VA Medical Center, Milwaukee, WI 53295, USA.
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7
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Circadian regulation of memory under stress: Endocannabinoids matter. Neurosci Biobehav Rev 2022; 138:104712. [PMID: 35643119 DOI: 10.1016/j.neubiorev.2022.104712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/27/2022] [Accepted: 05/23/2022] [Indexed: 11/24/2022]
Abstract
Organisms ranging from plants to higher mammals have developed 24-hour oscillation rhythms to optimize physiology to environmental changes and regulate a plethora of neuroendocrine and behavioral processes, including neurotransmitter and hormone regulation, stress response and learning and memory function. Compelling evidence indicates that a wide array of memory processes is strongly influenced by stress- and emotional arousal-activated neurobiological systems, including the endocannabinoid system which has been extensively shown to play an integral role in mediating stress effects on memory. Here, we review findings showing how circadian rhythms and time-of-day influence stress systems and memory performance. We report evidence of circadian regulation of memory under stress, focusing on the role of the endocannabinoid system and highlighting its circadian rhythmicity. Our discussion illustrates how the endocannabinoid system mediates stress effects on memory in a circadian-dependent fashion. We suggest that endocannabinoids might regulate molecular mechanisms that control memory function under circadian and stress influence, with potential important clinical implications for both neurodevelopmental disorders and psychiatric conditions involving memory impairments.
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Pirone A, Lazzarini G, Lenzi C, Giannessi E, Miragliotta V. Immunolocalization of cannabinoid receptor 1 (CB1), monoglyceride lipase (MGL) and fatty-acid amide hydrolase 1 (FAAH) in the pig claustrum. J Chem Neuroanat 2020; 109:101843. [DOI: 10.1016/j.jchemneu.2020.101843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/24/2020] [Accepted: 06/24/2020] [Indexed: 12/23/2022]
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Yamasaki T, Ohya T, Mori W, Zhang Y, Wakizaka H, Nengaki N, Fujinaga M, Kikuchi T, Zhang MR. Development of an In Vivo Method to Estimate Effective Drug Doses and Quantify Fatty Acid Amide Hydrolase in Rodent Brain using Positron Emission Tomography Tracer [ 11C]DFMC. J Pharmacol Exp Ther 2020; 373:353-360. [PMID: 32241809 DOI: 10.1124/jpet.119.263772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/27/2020] [Indexed: 11/22/2022] Open
Abstract
Fatty acid amide hydrolase (FAAH) is a key enzyme in the endocannabinoid system. N-(3,4-Dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[11C]methylphenyl)thiazol-2-yl]-1-carboxamide ([11C]DFMC) was developed as an irreversible-type positron emission tomography (PET) tracer for FAAH. Here, we attempted to noninvasively estimate rate constant k3 (rate of transfer to the specifically-bound compartment) as a direct index for FAAH in the rat brain. First, the two-tissue compartment model analysis including three parameters [K1-k3, two-tissue compartment model for the irreversible-type radiotracer (2TCMi)] in PET study with [11C]DFMC was conducted, which provided 0.21 ± 0.04 ml·cm-3·min-1 of the net uptake value (Ki), an indirect index for FAAH, in the FAAH-richest region (the cingulate cortex). Subsequently, to noninvasively estimate Ki value, the reference model analysis (Patlak graphical analysis reference model) was tried using a time-activity curve of the spinal cord. In that result, the noninvasive Ki value (KREF) was concisely estimated with high correlation (r > 0.95) to Ki values based on 2TCMi. Using estimated KREF value, we tried to obtain calculated-k3 based on previously defined equations. The calculated k3 was successfully estimated with high correlation (r = 0.95) to direct k3 in 2TCMi. Finally, the dose relationship study using calculated k3 demonstrated that in vivo ED50 value of [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate, a major inhibitor of FAAH, was 66.4 µg/kg in rat brain. In conclusion, we proposed the calculated k3 as an alternative index corresponding to regional FAAH concentrations and suggested that PET with [11C]DFMC enables occupancy study for new pharmaceuticals targeting FAAH. SIGNIFICANCE STATEMENT: In the present study, we proposed calculated k3 as an alternative index corresponding with fatty acid amide hydrolase concentration. By using calculated k3, in vivo ED50 of [3-(3-carbamoylphenyl)phenyl] N-cyclohexylcarbamate was successfully estimated to be 66.4 µg/kg for rats. Thus, we demonstrated the pharmacological utility of positron emission tomography with N-(3,4-dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[11C]methylphenyl)thiazol-2-yl]-1-carboxamide.
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Affiliation(s)
- Tomoteru Yamasaki
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Tomoyuki Ohya
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Wakana Mori
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Yiding Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Hidekatsu Wakizaka
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Nobuki Nengaki
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Masayuki Fujinaga
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Tatsuya Kikuchi
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
| | - Ming-Rong Zhang
- Department of Advanced Nuclear Medicine Sciences, National Institute of Radiological Sciences, Quantum Medical Science Directorate, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan (T.Y., T.O., W.M., Y.Z., H.W., N.N., M.F., T.K., M.-R.Z.) and SHI Accelerator Service Co. Ltd, Tokyo, Japan (N.N.)
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10
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Tripathi RKP. A perspective review on fatty acid amide hydrolase (FAAH) inhibitors as potential therapeutic agents. Eur J Med Chem 2019; 188:111953. [PMID: 31945644 DOI: 10.1016/j.ejmech.2019.111953] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 12/02/2019] [Accepted: 12/04/2019] [Indexed: 02/06/2023]
Abstract
Fatty acid amide hydrolase (FAAH) is an important enzyme creditworthy of hydrolyzing endocannabinoids and related-amidated signalling lipids, discovery of which has pioneered novel arena of pharmacological canvasses to unwrap its curative potency in various diseased circumstances. It presents contemporary basis for understanding molecules regulating and mediating inflammatory reactions, pain, anxiety, depression, and neurodegeneration. FAAH inhibitors form vital approach for discovery of therapeutic agents that are concerned with local elevation of endocannabinoids under certain stimuli, debarring adverse/unwanted secondary effects from global activation of cannabinoid receptors by exogenous cannabimimetics. During past decades, several molecules with excellent potency developed through tailor-made approaches entered into clinical trials, but none could reach market. Hence, hunt for novel, non-toxic and selective FAAH inhibitors are on horizon. This review summarizes present perception on FAAH in conjunction with its structure, mechanism of catalysis and biological functions. It also foregrounds recent development of molecules belonging to diverse chemical classes as potential FAAH inhibitors bobbing up from in-depth chemical, mechanistic and computational studies published since 2015-November 2019, focusing on their potency. This review will assist readers to obtain rationale on FAAH as potential target for addressing various disease conditions, acquiring significant knowledge on recently established inhibitor scaffolds and their development potentials. New technologies including MD-MM simulations and 3D-QSAR studies allow mechanistic characterization of enzyme. Assessment of in-vitro and in-vivo efficacy of existing FAAH inhibitors will facilitate researchers to design novel ligands utilizing modern drug design methods. The discussions will also impose precaution in decision making process, quashing possibility of late stage failure.
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Affiliation(s)
- Rati Kailash Prasad Tripathi
- Department of Pharmaceutical Science, Sushruta School of Medical and Paramedical Sciences, Assam University (A Central University), Silchar, Assam, 788011, India; Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering and Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India.
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11
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Wu MM, Zhang X, Asher MJ, Thayer SA. Druggable targets of the endocannabinoid system: Implications for the treatment of HIV-associated neurocognitive disorder. Brain Res 2019; 1724:146467. [PMID: 31539547 DOI: 10.1016/j.brainres.2019.146467] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/24/2022]
Abstract
HIV-associated neurocognitive disorder (HAND) affects nearly half of all HIV-infected individuals. Synaptodendritic damage correlates with neurocognitive decline in HAND, and many studies have demonstrated that HIV-induced neuronal injury results from excitotoxic and inflammatory mechanisms. The endocannabinoid (eCB) system provides on-demand protection against excitotoxicity and neuroinflammation. Here, we discuss evidence of the neuroprotective and anti-inflammatory properties of the eCB system from in vitro and in vivo studies. We examine the pharmacology of the eCB system and evaluate the therapeutic potential of drugs that modulate eCB signaling to treat HAND. Finally, we provide perspective on the need for additional studies to clarify the role of the eCB system in HIV neurotoxicity and speculate that strategies that enhance eCB signaling might slow cognitive decline in HAND.
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Affiliation(s)
- Mariah M Wu
- Graduate Program in Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| | - Xinwen Zhang
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| | - Melissa J Asher
- Graduate Program in Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| | - Stanley A Thayer
- Graduate Program in Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA; Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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12
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Zhu H, Xiang HC, Li HP, Lin LX, Hu XF, Zhang H, Meng WY, Liu L, Chen C, Shu Y, Zhang RY, Zhang P, Si JQ, Li M. Inhibition of GABAergic Neurons and Excitation of Glutamatergic Neurons in the Ventrolateral Periaqueductal Gray Participate in Electroacupuncture Analgesia Mediated by Cannabinoid Receptor. Front Neurosci 2019; 13:484. [PMID: 31156369 PMCID: PMC6533898 DOI: 10.3389/fnins.2019.00484] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/29/2019] [Indexed: 01/26/2023] Open
Abstract
Although electroacupuncture (EA) has become a worldwide practice, little is understood about its precise target in the central nervous system (CNS) and the cell type-specific analgesia mechanism. In the present study, we found that EA has significant antinociceptive effects both in inflammatory and neuropathic pain models. Chemogenetic inhibition of GABAergic neurons in the ventrolateral periaqueductal gray (vlPAG) replicated the effects of EA, whereas the combination of chemogenetic activation of GABAergic neurons and chemogenetic inhibition of glutamatergic neurons in the vlPAG was needed to reverse the effects of EA. Specifically knocking out CB1 receptors on GABAergic neurons in the vlPAG abolished the EA effect on pain hypersensitivity, while specifically knocking out CB1 receptors on glutamatergic neurons attenuated only a small portion of the EA effect. EA synchronously inhibits GABAergic neurons and activates glutamatergic neurons in the vlPAG through CB1 receptors to produce EA-induced analgesia. The CB1 receptors on GABAergic neurons localized in the vlPAG was the basis of the EA effect on pain hypersensitivity. This study provides new experimental evidence that EA can bidirectionally regulate GABAergic neurons and glutamatergic neurons via the CB1 receptors of the vlPAG to produce analgesia effects.
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Affiliation(s)
- He Zhu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China.,Department of Physiology, Medical College of Shihezi University, Shihezi, China
| | - Hong-Chun Xiang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Hong-Ping Li
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Li-Xue Lin
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Xue-Fei Hu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Hong Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Wang-Yang Meng
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Lu Liu
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Chao Chen
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Yang Shu
- Department of Central Laboratory, Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Ru-Yue Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Pei Zhang
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Jun-Qiang Si
- Department of Physiology, Medical College of Shihezi University, Shihezi, China
| | - Man Li
- Department of Neurobiology and Key Laboratory of Neurological Diseases of Ministry of Education, School of Basic Medicine, The Institute of Brain Research, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
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13
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Cannabinoids Stimulate the TRP Channel-Dependent Release of Both Serotonin and Dopamine to Modulate Behavior in C. elegans. J Neurosci 2019; 39:4142-4152. [PMID: 30886012 DOI: 10.1523/jneurosci.2371-18.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 02/04/2019] [Accepted: 03/08/2019] [Indexed: 01/01/2023] Open
Abstract
Cannabis sativa alters sensory perception and exhibits potential medicinal benefits. In mammals, cannabinoids activate two canonical receptors, CB1/CB2, as well additional receptors/ion channels whose overall contributions to cannabinoid signaling have yet to be fully assessed. In Caenorhabditis elegans, the endogenous cannabinoid receptor agonist, 2-arachidonoylglycerol (2-AG) activates a CB1 ortholog, NPR-19, to modulate behavior (Oakes et al., 2017). In addition, 2-AG stimulates the NPR-19 independent release of both serotonin (5-HT) and dopamine (DA) from subsets of monoaminergic neurons to modulate locomotory behaviors through a complex monoaminergic signaling pathway involving multiple serotonin and dopamine receptors. 2-AG also inhibits locomotion in remodeled monoamine receptor mutant animals designed to measure the acute release of either 5-HT or DA, confirming the direct effects of 2-AG on monoamine release. 2-AG-dependent locomotory inhibition requires the expression of transient receptor potential vanilloid 1 (TRPV1) and TRPN-like channels in the serotonergic or dopaminergic neurons, respectively, and the acute pharmacological inhibition of the TRPV1-like channel abolishes both 2-AG-dependent 5-HT release and locomotory inhibition, suggesting the 2-AG may activate the channel directly. This study highlights the advantages of identifying and assessing both CB1/CB2-dependent and independent cannabinoid signaling pathways in a genetically tractable, mammalian predictive model, where cannabinoid signaling at the molecular/neuronal levels can be correlated directly with changes in behavior.SIGNIFICANCE STATEMENT This study is focused on assessing CB1/CB2-independent cannabinoid signaling in a genetically tractable, whole-animal model where cannabinoid signaling at the molecular/neuronal levels can be correlated with behavioral change. Caenorhabditis elegans contains a cannabinoid signaling system mediated by a canonical cannabinoid receptor, NPR-19, with orthology to human CB1/CB2 (Oakes et al., 2017). The present study has characterized an NPR-19-independent signaling pathway that involves the cannabinoid-dependent release of both serotonin and dopamine and the expression of distinct TRP-like channels on the monoaminergic neurons. Our work should be of interest to those studying the complexities of CB1/CB2-independent cannabinoid signaling, the role of TRP channels in the modulation of monoaminergic signaling, and the cannabinoid-dependent modulation of behavior.
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14
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Scherma M, Masia P, Satta V, Fratta W, Fadda P, Tanda G. Brain activity of anandamide: a rewarding bliss? Acta Pharmacol Sin 2019; 40:309-323. [PMID: 30050084 DOI: 10.1038/s41401-018-0075-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/20/2018] [Indexed: 12/11/2022] Open
Abstract
Anandamide is a lipid mediator that acts as an endogenous ligand of CB1 receptors. These receptors are also the primary molecular target responsible for the pharmacological effects of Δ9-tetrahydrocannabinol, the psychoactive ingredient in Cannabis sativa. Several studies demonstrate that anandamide exerts an overall modulatory effect on the brain reward circuitry. Several reports suggest its involvement in the addiction-producing actions of other abused drugs, and it can also act as a behavioral reinforcer in animal models of drug abuse. Importantly, all these effects of anandamide appear to be potentiated by pharmacological inhibition of its metabolic degradation. Enhanced brain levels of anandamide after treatment with inhibitors of fatty acid amide hydrolase, the main enzyme responsible for its degradation, seem to affect the rewarding and reinforcing actions of many drugs of abuse. In this review, we will provide an overview from a preclinical perspective of the current state of knowledge regarding the behavioral pharmacology of anandamide, with a particular emphasis on its motivational/reinforcing properties. We will also discuss how modulation of anandamide levels through inhibition of enzymatic metabolic pathways could provide a basis for developing new pharmaco-therapeutic tools for the treatment of substance use disorders.
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15
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Calabrese EJ, Rubio-Casillas A. Biphasic effects of THC in memory and cognition. Eur J Clin Invest 2018; 48:e12920. [PMID: 29574698 DOI: 10.1111/eci.12920] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/11/2018] [Indexed: 12/20/2022]
Abstract
A generally undesired effect of cannabis smoking is a reversible disruption of short-term memory induced by delta-9-tetrahydrocannabinol (THC), the primary psychoactive component of cannabis. However, this paradigm has been recently challenged by a group of scientists who have shown that THC is also able to improve neurological function in old animals when chronically administered at low concentrations. Moreover, recent studies demonstrated that THC paradoxically promotes hippocampal neurogenesis, prevents neurodegenerative processes occurring in animal models of Alzheimer's disease, protects from inflammation-induced cognitive damage and restores memory and cognitive function in old mice. With the aim to reconcile these seemingly contradictory facts, this work will show that such paradox can be explained within the framework of hormesis, defined as a biphasic dose-response.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Amherst, MA, USA
| | - Alberto Rubio-Casillas
- Laboratorio de Biologia, Escuela Preparatoria Regional de Autlán, Universidad de Guadalajara, Jalisco, México
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16
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Natividad LA, Buczynski MW, Herman MA, Kirson D, Oleata CS, Irimia C, Polis I, Ciccocioppo R, Roberto M, Parsons LH. Constitutive Increases in Amygdalar Corticotropin-Releasing Factor and Fatty Acid Amide Hydrolase Drive an Anxious Phenotype. Biol Psychiatry 2017; 82:500-510. [PMID: 28209423 PMCID: PMC5509512 DOI: 10.1016/j.biopsych.2017.01.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/21/2016] [Accepted: 01/04/2017] [Indexed: 01/15/2023]
Abstract
BACKGROUND Corticotropin-releasing factor (CRF) mediates anxiogenic responses by activating CRF type 1 (CRF1) receptors in limbic brain regions. Anxiety is further modulated by the endogenous cannabinoid (eCB) system that attenuates the synaptic effects of stress. In the amygdala, acute stress activates the enzymatic clearance of the eCB N-arachidonoylethanolamine via fatty acid amide hydrolase (FAAH), although it is unclear whether chronic dysregulation of CRF systems induces maladaptive changes in amygdalar eCB signaling. Here, we used genetically selected Marchigian Sardinian P (msP) rats carrying an innate overexpression of CRF1 receptors to study the role of constitutive upregulation in CRF systems on amygdalar eCB function and persistent anxiety-like effects. METHODS We applied behavioral, pharmacological, and biochemical methods to broadly characterize anxiety-like behaviors and amygdalar eCB clearance enzymes in msP versus nonselected Wistar rats. Subsequent studies examined the influence of dysregulated CRF and FAAH systems in altering excitatory transmission in the central amygdala (CeA). RESULTS msPs display an anxious phenotype accompanied by elevations in amygdalar FAAH activity and reduced dialysate N-arachidonoylethanolamine levels in the CeA. Elevations in CRF-CRF1 signaling dysregulate FAAH activity, and this genotypic difference is normalized with pharmacological blockade of CRF1 receptors. msPs also exhibit elevated baseline glutamatergic transmission in the CeA, and dysregulated CRF-FAAH facilitates stress-induced increases in glutamatergic activity. Treatment with an FAAH inhibitor relieves sensitized glutamatergic responses in msPs and attenuates the anxiety-like phenotype. CONCLUSIONS Pathological anxiety and stress hypersensitivity are driven by constitutive increases in CRF1 signaling that dysregulate N-arachidonoylethanolamine signaling mechanisms and reduce neuronal inhibitory control of CeA glutamatergic synapses.
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Affiliation(s)
- Luis A Natividad
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Matthew W Buczynski
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California; Virginia Tech School of Neuroscience, Virginia Tech, Blacksburg, Virginia
| | - Melissa A Herman
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Dean Kirson
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Christopher S Oleata
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Cristina Irimia
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Ilham Polis
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Roberto Ciccocioppo
- School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Marisa Roberto
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
| | - Loren H Parsons
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
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17
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Starowicz K, Finn DP. Cannabinoids and Pain: Sites and Mechanisms of Action. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 80:437-475. [PMID: 28826543 DOI: 10.1016/bs.apha.2017.05.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The endocannabinoid system, consisting of the cannabinoid1 receptor (CB1R) and cannabinoid2 receptor (CB2R), endogenous cannabinoid ligands (endocannabinoids), and metabolizing enzymes, is present throughout the pain pathways. Endocannabinoids, phytocannabinoids, and synthetic cannabinoid receptor agonists have antinociceptive effects in animal models of acute, inflammatory, and neuropathic pain. CB1R and CB2R located at peripheral, spinal, or supraspinal sites are important targets mediating these antinociceptive effects. The mechanisms underlying the analgesic effects of cannabinoids likely include inhibition of presynaptic neurotransmitter and neuropeptide release, modulation of postsynaptic neuronal excitability, activation of the descending inhibitory pain pathway, and reductions in neuroinflammatory signaling. Strategies to dissociate the psychoactive effects of cannabinoids from their analgesic effects have focused on peripherally restricted CB1R agonists, CB2R agonists, inhibitors of endocannabinoid catabolism or uptake, and modulation of other non-CB1R/non-CB2R targets of cannabinoids including TRPV1, GPR55, and PPARs. The large body of preclinical evidence in support of cannabinoids as potential analgesic agents is supported by clinical studies demonstrating their efficacy across a variety of pain disorders.
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Affiliation(s)
- Katarzyna Starowicz
- Institute of Pharmacology, Polish Academy of Sciences, Laboratory of Pain Pathophysiology, Krakow, Poland
| | - David P Finn
- Pharmacology and Therapeutics, School of Medicine, Galway Neuroscience Centre and Centre for Pain Research, NCBES, National University of Ireland, Galway, Ireland.
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18
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Thomas BF. Interactions of Cannabinoids With Biochemical Substrates. SUBSTANCE ABUSE-RESEARCH AND TREATMENT 2017; 11:1178221817711418. [PMID: 28607542 PMCID: PMC5457144 DOI: 10.1177/1178221817711418] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 02/13/2017] [Indexed: 01/02/2023]
Abstract
Recent decades have seen much progress in the identification and characterization of cannabinoid receptors and the elucidation of the mechanisms by which derivatives of the Cannabis sativa plant bind to receptors and produce their physiological and psychological effects. The information generated in this process has enabled better understanding of the fundamental physiological and psychological processes controlled by the central and peripheral nervous systems and has fostered the development of natural and synthetic cannabinoids as therapeutic agents. A negative aspect of this decades-long effort is the proliferation of clandestinely synthesized analogs as recreational street drugs with dangerous effects. Currently, the interactions of cannabinoids with their biochemical substrates are extensively but inadequately understood, and the clinical application of derived and synthetic receptor ligands remains quite limited. The wide anatomical distribution and functional complexity of the cannabinoid system continue to indicate potential for both therapeutic and side effects, which offers challenges and opportunities for medicinal chemists involved in drug discovery and development.
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Affiliation(s)
- Brian F Thomas
- Analytical Chemistry and Pharmaceutics, RTI International, Research Triangle Park, NC, USA
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19
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Patel S, Hill MN, Cheer JF, Wotjak CT, Holmes A. The endocannabinoid system as a target for novel anxiolytic drugs. Neurosci Biobehav Rev 2017; 76:56-66. [PMID: 28434588 PMCID: PMC5407316 DOI: 10.1016/j.neubiorev.2016.12.033] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/22/2016] [Accepted: 12/16/2016] [Indexed: 12/01/2022]
Abstract
The endocannabinoid (eCB) system has attracted attention for its role in various behavioral and brain functions, and as a therapeutic target in neuropsychiatric disease states, including anxiety disorders and other conditions resulting from dysfunctional responses to stress. In this mini-review, we highlight components of the eCB system that offer potential 'druggable' targets for new anxiolytic medications, emphasizing some of the less well-discussed options. We discuss how selectively amplifying eCBs recruitment by interfering with eCB-degradation, via fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), has been linked to reductions in anxiety-like behaviors in rodents and variation in human anxiety symptoms. We also discuss a non-canonical route to regulate eCB degradation that involves interfering with cyclooxygenase-2 (COX-2). Next, we discuss approaches to targeting eCB receptor-signaling in ways that do not involve the cannabinoid receptor subtype 1 (CB1R); by targeting the CB2R subtype and the transient receptor potential vanilloid type 1 (TRPV1). Finally, we review evidence that cannabidiol (CBD), while representing a less specific pharmacological approach, may be another way to modulate eCBs and interacting neurotransmitter systems to alleviate anxiety. Taken together, these various approaches provide a range of plausible paths to developing novel compounds that could prove useful for treating trauma-related and anxiety disorders.
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Affiliation(s)
- Sachin Patel
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, USA; Vanderbilt Kennedy Center for Human Development, Vanderbilt University Medical Center, Nashville, USA
| | - Mathew N Hill
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Mathison Centre for Mental Health Research and Education, University of Calgary, Calgary, AB, Canada; Departments of Cell Biology and Anatomy and Psychiatry, University of Calgary, Calgary, AB, Canada
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology and Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Carsten T Wotjak
- Max Planck Institute of Psychiatry, Department of Stress Neurobiology & Neurogenetics, Munich, Germany
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
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Dean C, Hillard CJ, Seagard JL, Hopp FA, Hogan QH. Upregulation of fatty acid amide hydrolase in the dorsal periaqueductal gray is associated with neuropathic pain and reduced heart rate in rats. Am J Physiol Regul Integr Comp Physiol 2017; 312:R585-R596. [PMID: 28148494 DOI: 10.1152/ajpregu.00481.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/26/2017] [Accepted: 01/31/2017] [Indexed: 11/22/2022]
Abstract
Nerve damage can induce a heightened pain response to noxious stimulation, which is termed hyperalgesia. Pain itself acts as a stressor, initiating autonomic and sensory effects through the dorsal periaqueductal gray (dPAG) to induce both sympathoexcitation and analgesia, which prior studies have shown to be affected by endocannabinoid signaling. The present study addressed the hypothesis that neuropathic pain disrupts autonomic and analgesic regulation by endocannabinoid signaling in the dPAG. Endocannabinoid contents, transcript levels of endocannabinoid signaling components, and catabolic enzyme activity were analyzed in the dPAG of rats at 21 days after painful nerve injury. The responses to two nerve injury models were similar, with two-thirds of animals developing hyperalgesia that was maintained throughout the postinjury period, whereas no sustained change in sensory function was observed in the remaining rats. Anandamide content was lower in the dPAG of rats that developed sustained hyperalgesia, and activity of the catabolic enzyme fatty acid amide hydrolase (FAAH) was higher. Intensity of hyperalgesia was correlated to transcript levels of FAAH and negatively correlated to heart rate and sympathovagal balance. These data suggest that maladaptive endocannabinoid signaling in the dPAG after nerve injury could contribute to chronic neuropathic pain and associated autonomic dysregulation. This study demonstrates that reduced anandamide content and upregulation of FAAH in the dPAG are associated with hyperalgesia and reduced heart rate sustained weeks after nerve injury. These data provide support for the evaluation of FAAH inhibitors for the treatment of chronic neuropathic pain.
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Affiliation(s)
- Caron Dean
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; .,Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Cecilia J Hillard
- Department of Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Jeanne L Seagard
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin.,Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Francis A Hopp
- Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin.,Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
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22
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Hillard CJ, Beatka M, Sarvaideo J. Endocannabinoid Signaling and the Hypothalamic-Pituitary-Adrenal Axis. Compr Physiol 2016; 7:1-15. [PMID: 28134998 DOI: 10.1002/cphy.c160005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The elucidation of Δ9-tetrahydrocannabinol as the active principal of Cannabis sativa in 1963 initiated a fruitful half-century of scientific discovery, culminating in the identification of the endocannabinoid signaling system, a previously unknown neuromodulatory system. A primary function of the endocannabinoid signaling system is to maintain or recover homeostasis following psychological and physiological threats. We provide a brief introduction to the endocannabinoid signaling system and its role in synaptic plasticity. The majority of the article is devoted to a summary of current knowledge regarding the role of endocannabinoid signaling as both a regulator of endocrine responses to stress and as an effector of glucocorticoid and corticotrophin-releasing hormone signaling in the brain. We summarize data demonstrating that cannabinoid receptor 1 (CB1R) signaling can both inhibit and potentiate the activation of the hypothalamic-pituitary-adrenal axis by stress. We present a hypothesis that the inhibitory arm has high endocannabinoid tone and also serves to enhance recovery to baseline following stress, while the potentiating arm is not tonically active but can be activated by exogenous agonists. We discuss recent findings that corticotropin-releasing hormone in the amygdala enables hypothalamic-pituitary-adrenal axis activation via an increase in the catabolism of the endocannabinoid N-arachidonylethanolamine. We review data supporting the hypotheses that CB1R activation is required for many glucocorticoid effects, particularly feedback inhibition of hypothalamic-pituitary-adrenal axis activation, and that glucocorticoids mobilize the endocannabinoid 2-arachidonoylglycerol. These features of endocannabinoid signaling make it a tantalizing therapeutic target for treatment of stress-related disorders but to date, this promise is largely unrealized. © 2017 American Physiological Society. Compr Physiol 7:1-15, 2017.
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Affiliation(s)
- Cecilia J Hillard
- Department of Pharmacology and Toxicology, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Margaret Beatka
- Department of Pharmacology and Toxicology, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Jenna Sarvaideo
- Department of Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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23
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Matricon J, Seillier A, Giuffrida A. Distinct neuronal activation patterns are associated with PCP-induced social withdrawal and its reversal by the endocannabinoid-enhancing drug URB597. Neurosci Res 2016; 110:49-58. [PMID: 27091613 PMCID: PMC5007165 DOI: 10.1016/j.neures.2016.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 10/21/2022]
Abstract
The fatty acid amide hydrolase inhibitor, URB597, an endocannabinoid enhancing drug, reverses social withdrawal in the sub-chronic PCP rat model of schizophrenia, but reduces social interaction (SI) in controls. To identify the anatomical substrates associated with PCP-induced social withdrawal and the contrasting effects of URB597 on SI in PCP- versus saline-treated rats, we analyzed SI-induced c-Fos expression in 28 brain areas relevant to schizophrenia and/or social behavior following vehicle or URB597 administration. In saline-treated rats, SI was accompanied by changes in c-Fos expression in the infralimbic and orbitofrontal cortices, dorsomedial caudate putamen, ventrolateral nucleus of the septum, dorsolateral periaqueductal gray (dlPAG) and central amygdala. Except for the dlPAG, these changes were not observed in PCP-treated rats or in saline-treated rats receiving URB597. In the dorsomedial part of the bed nucleus of the stria terminalis (dmBNST), SI-induced c-Fos expression was observed only in PCP-treated rats. Interestingly, URB597 in PCP-treated rats restored a similar c-Fos expression pattern as observed in saline-treated rats: activation of the orbitofrontal cortex, inhibition of the central amygdala and suppression of activation of the dmBNST. These data suggest that orbitofrontal cortex, central amygdala and dmBNST play a critical role in the reversal of PCP-induced social withdrawal by URB597.
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Affiliation(s)
- Julien Matricon
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
| | - Alexandre Seillier
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
| | - Andrea Giuffrida
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
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Park HY, Ryu YK, Go J, Son E, Kim KS, Kim MR. Palmitoyl Serotonin Inhibits L-dopa-induced Abnormal Involuntary Movements in the Mouse Parkinson Model. Exp Neurobiol 2016; 25:174-84. [PMID: 27574484 PMCID: PMC4999423 DOI: 10.5607/en.2016.25.4.174] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/21/2016] [Accepted: 07/25/2016] [Indexed: 12/12/2022] Open
Abstract
L-3,4-dihydroxyphenylalanine (L-DOPA) is the most common treatment for patients with Parkinson's disease (PD). However, long term use of L-DOPA for PD therapy lead to abnormal involuntary movements (AIMs) known as dyskinesia. Fatty acid amide hydrolase (FAAH) is enriched protein in basal ganglia, and inhibition of the protein reduces dyskinetic behavior of mice. Palmitoyl serotonin (PA-5HT) is a hybrid molecule patterned after arachidonoyl serotonin, antagonist of FAAH. However, the effect of PA-5HT on L-DOPA-induced dyskinesia (LID) in PD have not yet been elucidated. To investigate whether PA-5HT relieve LID in PD and decrease hyperactivation of dopamine D1 receptors, we used the 6-hydroxydopomine (6-OHDA)-lesioned mouse model of PD and treated the L-DOPA (20 mg/kg) for 10 days with PA-5HT (0.3 mg/kg/day). The number of wall contacts with the forelimb in the cylinder test was significantly decreased by 6-OHDA lesion in mice and the pharmacotherapeutic effect of L-DOPA was also revealed in PA-5HT-treated mice. Moreover, in AIMs test, PA-5HT-treated mice showed significant reduction of locomotive, axial, limb, and orofacial AIMs score compared to the vehicle-treated mice. LID-induced hyper-phosphorylation of ERK1/2 and overexpression of FosB/ΔFosB was markedly decreased in 6-OHDA-lesioned striatum of PA-5HT-treated mice, indicating that PA-5HT decreased the dopamine D1 receptor-hyperactivation induced by chronic treatment of L-DOPA in dopamine-denervated striatum. These results suggest that PA-5HT effectively attenuates the development of LID and enhance of ERK1/2 phosphorylation and FosB/ΔFosB expression in the hemi-parkinsonian mouse model. PA-5HT may have beneficial effect on the LID in PD.
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Affiliation(s)
- Hye-Yeon Park
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea.; Department of Food and Nutrition, Chung-Nam National University, Daejeon 34134, Korea
| | - Young-Kyoung Ryu
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
| | - Jun Go
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
| | - Eunjung Son
- Department of Food and Nutrition, Chung-Nam National University, Daejeon 34134, Korea
| | - Kyoung-Shim Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea.; University of Science and Technology, Daejeon 34113, Korea
| | - Mee Ree Kim
- Department of Food and Nutrition, Chung-Nam National University, Daejeon 34134, Korea
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Olmo IG, Ferreira-Vieira TH, Ribeiro FM. Dissecting the Signaling Pathways Involved in the Crosstalk between Metabotropic Glutamate 5 and Cannabinoid Type 1 Receptors. Mol Pharmacol 2016; 90:609-619. [PMID: 27338080 DOI: 10.1124/mol.116.104372] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/16/2016] [Indexed: 02/06/2023] Open
Abstract
The metabotropic glutamate 5 receptor and the cannabinoid type 1 receptor are G protein-coupled receptors that are widely expressed in the central nervous system. Metabotropic glutamate 5 receptors, present at the postsynaptic site, are coupled to Gαq/11 proteins and display an excitatory response upon activation, whereas the cannabinoid type 1 receptor, mainly present at presynaptic terminals, is coupled to the Gi/o protein and triggers an inhibitory response. Recent studies suggest that the glutamatergic and endocannabinoid systems exhibit a functional interaction to modulate several neural processes. In this review, we discuss possible mechanisms involved in this crosstalk and its relationship with physiologic and pathologic conditions, including nociception, addiction, and fragile X syndrome.
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Affiliation(s)
- Isabella G Olmo
- Department of Biochemistry and Immunology, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Talita H Ferreira-Vieira
- Department of Biochemistry and Immunology, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fabiola M Ribeiro
- Department of Biochemistry and Immunology, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Dean C, Hillard CJ, Seagard JL, Hopp FA, Hogan QH. Components of the cannabinoid system in the dorsal periaqueductal gray are related to resting heart rate. Am J Physiol Regul Integr Comp Physiol 2016; 311:R254-62. [PMID: 27280429 DOI: 10.1152/ajpregu.00154.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/05/2016] [Indexed: 11/22/2022]
Abstract
The present study was undertaken to examine whether variations in endocannabinoid signaling in the dorsal periaqueductal gray (dPAG) are associated with baseline autonomic nerve activity, heart rate, and blood pressure. Blood pressure was recorded telemetrically in rats, and heart rate and power spectral analysis of heart rate variability were determined. Natural variations from animal to animal provided a range of baseline values for analysis. Transcript levels of endocannabinoid signaling components in the dPAG were analyzed, and endocannabinoid content and catabolic enzyme activity were measured. Higher baseline heart rate was associated with increased anandamide content and with decreased activity of the anandamide-hydrolyzing enzyme, fatty acid amide hydrolase (FAAH), and it was negatively correlated with transcript levels of both FAAH and monoacylglycerol lipase (MAGL), a catabolic enzyme for 2-arachidonoylglycerol (2-AG). Autonomic tone and heart rate, but not blood pressure, were correlated to levels of FAAH mRNA. In accordance with these data, exogenous anandamide in the dPAG of anesthetized rats increased heart rate. These data indicate that in the dPAG, anandamide, a FAAH-regulated lipid, contributes to regulation of baseline heart rate through influences on autonomic outflow.
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Affiliation(s)
- Caron Dean
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Cecilia J Hillard
- Department of Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Jeanne L Seagard
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Francis A Hopp
- Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Quinn H Hogan
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin
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Aliczki M, Barna I, Till I, Baranyi M, Sperlagh B, Goldberg SR, Haller J. The effects anandamide signaling in the prelimbic cortex and basolateral amygdala on coping with environmental stimuli in rats. Psychopharmacology (Berl) 2016; 233:1889-99. [PMID: 26809457 DOI: 10.1007/s00213-016-4219-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/18/2016] [Indexed: 01/25/2023]
Abstract
RATIONALE Several lines of recent evidence suggest that endocannabinoids affect behavior by influencing the general patterns of challenge responding. OBJECTIVES Here, we investigated the brain mechanisms underlying this phenomenon in rats. METHODS The anandamide hydrolysis inhibitor URB597 was condensed into the tip of stainless steel cannulae, which were chronically implanted slightly above the prelimbic cortex (PRL) or the basolateral amygdala (BLA), two important regions of coping and endocannabinoid action. Thereafter, we investigated behavioral responsiveness to ambient light level in the elevated plus-maze and conditioned fear tests. RESULTS URB597 concentration was ~30 μg/mg protein in target areas; local brain anandamide levels increased threefold, without significant changes in 2-arachidonoylglycerol. High levels of illumination halved the time spent by controls in the open arms of the plus-maze. No similar decrease was observed in rats with URB597 implants in the PRL. High light decreased conditioned fear by 30 % in controls, but not in rats with prelimbic URB597 implants. Unresponsiveness to environmental challenges was not attributable to the anxiolytic effects of anandamide enhancement, as implants induced paradoxical anxiogenic-like effects under low light, which could be explained by effects on stimulus responsiveness rather than by effects on anxiety. URB597 implants targeting the BLA did not affect stimulus responsiveness. CONCLUSIONS Our findings show that elevated prelimbic anandamide signaling leads to less environment-dependent (more autonomous) behavioral responses to challenges, which is an attribute of active coping styles. These findings are discussed in light of two emerging concepts of endocannabinoid roles, particularly "emotional homeostasis" and "active coping."
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Affiliation(s)
- Mano Aliczki
- Department of Behavioural Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1450, Budapest, P.O. Box 67, Hungary
| | - Istvan Barna
- Department of Behavioural Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1450, Budapest, P.O. Box 67, Hungary
| | - Ibolya Till
- Department of Behavioural Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1450, Budapest, P.O. Box 67, Hungary
| | - Maria Baranyi
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Beata Sperlagh
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Steven R Goldberg
- Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Jozsef Haller
- Department of Behavioural Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1450, Budapest, P.O. Box 67, Hungary.
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Pirone A, Cantile C, Miragliotta V, Lenzi C, Giannessi E, Cozzi B. Immunohistochemical distribution of the cannabinoid receptor 1 and fatty acid amide hydrolase in the dog claustrum. J Chem Neuroanat 2016; 74:21-7. [PMID: 26907575 DOI: 10.1016/j.jchemneu.2016.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 02/10/2016] [Accepted: 02/11/2016] [Indexed: 12/01/2022]
Abstract
Cannabinoid receptor 1 (CB1R) and fatty acid amide hydrolase (FAAH) are part of the endocannabinoid system (ECB) which exerts a neuromodulatory activity on different brain functions and plays a key role in neurogenesis. Although many studies have reported FAAH and CB1R expression in the brain of different animal species, to the best of our knowledge they have never been described in the canine claustrum. Claustrum samples, obtained from necropsy of four neurologically normal dogs, were formalin fixed for paraffin embedding. Sections were either stained for morpho-histological analysis or immunostained for CB1R and FAAH. Analysis of adjacent sections incubated with the two antisera showed a complementary labeling pattern in the claustrum, with CB1R antibody staining fibers while anti-FAAH antibody stained cell bodies and the proximal portion of dendrites; this particular anatomical relationship suggests a retrograde endocannabinoid action via CB1R. CB1R and FAAH complementary immunostaining and their cellular localization reported here provide the first anatomical evidence for existence of the ECB in the dog claustrum.
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Affiliation(s)
- Andrea Pirone
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
| | - Carlo Cantile
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | | | - Carla Lenzi
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | | | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padua, Padua, Italy
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29
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Viader A, Ogasawara D, Joslyn CM, Sanchez-Alavez M, Mori S, Nguyen W, Conti B, Cravatt BF. A chemical proteomic atlas of brain serine hydrolases identifies cell type-specific pathways regulating neuroinflammation. eLife 2016; 5:e12345. [PMID: 26779719 PMCID: PMC4737654 DOI: 10.7554/elife.12345] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/13/2015] [Indexed: 12/19/2022] Open
Abstract
Metabolic specialization among major brain cell types is central to nervous system function and determined in large part by the cellular distribution of enzymes. Serine hydrolases are a diverse enzyme class that plays fundamental roles in CNS metabolism and signaling. Here, we perform an activity-based proteomic analysis of primary mouse neurons, astrocytes, and microglia to furnish a global portrait of the cellular anatomy of serine hydrolases in the brain. We uncover compelling evidence for the cellular compartmentalization of key chemical transmission pathways, including the functional segregation of endocannabinoid (eCB) biosynthetic enzymes diacylglycerol lipase-alpha (DAGLα) and –beta (DAGLβ) to neurons and microglia, respectively. Disruption of DAGLβ perturbed eCB-eicosanoid crosstalk specifically in microglia and suppressed neuroinflammatory events in vivo independently of broader effects on eCB content. Mapping the cellular distribution of metabolic enzymes thus identifies pathways for regulating specialized inflammatory responses in the brain while avoiding global alterations in CNS function. DOI:http://dx.doi.org/10.7554/eLife.12345.001 The brain is made up of many types of cells. These include the neurons that transmit messages throughout the nervous system, and microglia, which act as the first line of the brain’s immune defense. The activity of both neurons and microglia can be influenced by molecules called endocannabinoids that bind to proteins on the cells’ surface. For example, endocannabinoids affect how a neuron responds to messages sent to it from a neighbouring neuron, and help microglia to regulate the inflammation of brain tissue. Enzymes called serine hydrolases play important roles in several different signaling processes in the brain, including those involving endocannabinoids. Viader et al. have now studied the activities of these enzymes – including two called DAGLα and DAGLβ – in the mouse brain using a technique called activity-based protein profiling. This revealed that DAGLα plays an important role in controlling how neurons respond to endocannabinoids, while DAGLβ performs the equivalent role in microglia. When Viader et al. shut down DAGLβ activity, this only affected endocannabinoid signaling in microglia. This also had the effect of reducing inflammation in the brain, without affecting how endocannabinoids signal in neurons. These results suggest that inhibitors of DAGLβ could offer a way to suppress inflammation in the brain, which may contribute to neuropsychiatric and neurodegenerative diseases, while preserving the normal pathways that neurons use to communicate with one another. DOI:http://dx.doi.org/10.7554/eLife.12345.002
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Affiliation(s)
- Andreu Viader
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States.,Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
| | - Daisuke Ogasawara
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States.,Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
| | - Christopher M Joslyn
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States.,Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
| | - Manuel Sanchez-Alavez
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States
| | - Simone Mori
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States
| | - William Nguyen
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States
| | - Bruno Conti
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States
| | - Benjamin F Cravatt
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States.,Department of Chemical Physiology, The Scripps Research Institute, La Jolla, United States
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30
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Appiah-Kusi E, Leyden E, Parmar S, Mondelli V, McGuire P, Bhattacharyya S. Abnormalities in neuroendocrine stress response in psychosis: the role of endocannabinoids. Psychol Med 2016; 46:27-45. [PMID: 26370602 DOI: 10.1017/s0033291715001786] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The aim of this article is to summarize current evidence regarding alterations in the neuroendocrine stress response system and endocannabinoid system and their relationship in psychotic disorders such as schizophrenia. Exposure to stress is linked to the development of a number of psychiatric disorders including psychosis. However, the precise role of stress in the development of psychosis and the possible mechanisms that might underlie this are not well understood. Recently the cannabinoid hypothesis of schizophrenia has emerged as a potential line of enquiry. Endocannabinoid levels are increased in patients with psychosis compared with healthy volunteers; furthermore, they increase in response to stress, which suggests another potential mechanism for how stress might be a causal factor in the development of psychosis. However, research regarding the links between stress and the endocannabinoid system is in its infancy. Evidence summarized here points to an alteration in the baseline tone and reactivity of the hypothalamic-pituitary-adrenal (HPA) axis as well as in various components of the endocannabinoid system in patients with psychosis. Moreover, the precise nature of the inter-relationship between these two systems is unclear in man, especially their biological relevance in the context of psychosis. Future studies need to simultaneously investigate HPA axis and endocannabinoid alterations both at baseline and following experimental perturbation in healthy individuals and those with psychosis to understand how they interact with each other in health and disease and obtain mechanistic insight as to their relevance to the pathophysiology of schizophrenia.
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Affiliation(s)
- E Appiah-Kusi
- Department of Psychosis Studies,King's College London,Institute of Psychiatry,Psychology & Neuroscience (IoPPN),PO Box 63,De Crespigny Park,Denmark Hill,London SE5 8AF,UK
| | - E Leyden
- Department of Psychosis Studies,King's College London,Institute of Psychiatry,Psychology & Neuroscience (IoPPN),PO Box 63,De Crespigny Park,Denmark Hill,London SE5 8AF,UK
| | - S Parmar
- Department of Psychosis Studies,King's College London,Institute of Psychiatry,Psychology & Neuroscience (IoPPN),PO Box 63,De Crespigny Park,Denmark Hill,London SE5 8AF,UK
| | - V Mondelli
- Department of Psychological Medicine,King's College London,Institute of Psychiatry,Psychology & Neuroscience (IoPPN),PO Box 92,De Crespigny Park,Denmark Hill,London SE5 8AF,UK
| | - P McGuire
- Department of Psychosis Studies,King's College London,Institute of Psychiatry,Psychology & Neuroscience (IoPPN),PO Box 63,De Crespigny Park,Denmark Hill,London SE5 8AF,UK
| | - S Bhattacharyya
- Department of Psychosis Studies,King's College London,Institute of Psychiatry,Psychology & Neuroscience (IoPPN),PO Box 63,De Crespigny Park,Denmark Hill,London SE5 8AF,UK
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Abstract
The endocannabinoid system consists of endogenous cannabinoids (endocannabinoids), the enzymes that synthesize and degrade endocannabinoids, and the receptors that transduce the effects of endocannabinoids. Much of what we know about the function of endocannabinoids comes from studies that combine localization of endocannabinoid system components with physiological or behavioral approaches. This review will focus on the localization of the best-known components of the endocannabinoid system for which the strongest anatomical evidence exists.
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Shoup TM, Bonab AA, Wilson AA, Vasdev N. Synthesis and preclinical evaluation of [¹⁸F]FCHC for neuroimaging of fatty acid amide hydrolase. Mol Imaging Biol 2015; 17:257-63. [PMID: 25273322 DOI: 10.1007/s11307-014-0789-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE Fatty acid amide hydrolase (FAAH), a catabolic enzyme which regulates lipid transmitters in the endocannabinoid system, is an avidly sought therapeutic and positron emission tomography (PET) imaging target for studies involving addiction and neurological disorders. We report the synthesis of a new fluorine-18-labeled FAAH inhibitor, trans-3-(4, 5-dihydrooxazol-2-yl)phenyl-4-[(18)F]fluorocyclohexylcarbamate ([(18)F]FCHC), and its evaluation in rat brain. PROCEDURES The synthesis of [(18)F]FCHC was conducted via a 3-step, 1-pot reaction, resulting in uncorrected radiochemical yields between 10 and 20% (n = 5) relative to [(18)F]fluoride, with specific activities of >5 Ci/μmol at the end of the synthesis. The radiosynthesis was seamlessly automated using a commercial radiofluorination apparatus. Ex vivo biodistribution and preliminary PET imaging studies were carried out in male Sprague-Dawley rats. RESULTS Rat brain biodistribution at 2 min post-injection showed a standard uptake value of 4.6 ± 0.1 in the cortex, which increased to 7.8 ± 0.1 at 40 min. Pretreatment with the selective FAAH inhibitor URB597 reduced uptake of radioactivity in all brain regions by >90%, with 98 % blockade in the FAAH-rich cortex. PET imaging was consistent with biodistribution studies. CONCLUSIONS [(18)F]FCHC appears to be a highly sensitive (18)F-labeled radiotracer for imaging FAAH in the central nervous system, and these results warrant further imaging in nonhuman primates.
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Affiliation(s)
- Timothy M Shoup
- Division of Nuclear Medicine and Molecular Imaging, Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital, and Department of Radiology, Harvard Medical School, Boston, MA, USA
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Hillard CJ. The Endocannabinoid Signaling System in the CNS: A Primer. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 125:1-47. [PMID: 26638763 DOI: 10.1016/bs.irn.2015.10.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The purpose of this chapter is to provide an introduction to the mechanisms for the regulation of endocannabinoid signaling through CB1 cannabinoid receptors in the central nervous system. The processes involved in the synthesis and degradation of the two most well-studied endocannabinoids, 2-arachidonoylglycerol and N-arachidonylethanolamine are outlined along with information regarding the regulation of the proteins involved. Signaling mechanisms and pharmacology of the CB1 cannabinoid receptor are outlined, as is the paradigm of endocannabinoid/CB1 receptor regulation of neurotransmitter release. The reader is encouraged to appreciate the importance of the endocannabinoid/CB1 receptor signaling system in the regulation of synaptic activity in the brain.
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Affiliation(s)
- Cecilia J Hillard
- Neuroscience Research Center, and Department of Pharmacology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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34
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Abstract
Corticotropin-releasing hormone (CRH) is a central integrator in the brain of endocrine and behavioral stress responses, whereas activation of the endocannabinoid CB1 receptor suppresses these responses. Although these systems regulate overlapping functions, few studies have investigated whether these systems interact. Here we demonstrate a novel mechanism of CRH-induced anxiety that relies on modulation of endocannabinoids. Specifically, we found that CRH, through activation of the CRH receptor type 1 (CRHR1), evokes a rapid induction of the enzyme fatty acid amide hydrolase (FAAH), which causes a reduction in the endocannabinoid anandamide (AEA), within the amygdala. Similarly, the ability of acute stress to modulate amygdala FAAH and AEA in both rats and mice is also mediated through CRHR1 activation. This interaction occurs specifically in amygdala pyramidal neurons and represents a novel mechanism of endocannabinoid-CRH interactions in regulating amygdala output. Functionally, we found that CRH signaling in the amygdala promotes an anxious phenotype that is prevented by FAAH inhibition. Together, this work suggests that rapid reductions in amygdala AEA signaling following stress may prime the amygdala and facilitate the generation of downstream stress-linked behaviors. Given that endocannabinoid signaling is thought to exert "tonic" regulation on stress and anxiety responses, these data suggest that CRH signaling coordinates a disruption of tonic AEA activity to promote a state of anxiety, which in turn may represent an endogenous mechanism by which stress enhances anxiety. These data suggest that FAAH inhibitors may represent a novel class of anxiolytics that specifically target stress-induced anxiety.
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Corcoran L, Roche M, Finn DP. The Role of the Brain's Endocannabinoid System in Pain and Its Modulation by Stress. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 125:203-55. [DOI: 10.1016/bs.irn.2015.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Gamaleddin IH, Trigo JM, Gueye AB, Zvonok A, Makriyannis A, Goldberg SR, Le Foll B. Role of the endogenous cannabinoid system in nicotine addiction: novel insights. Front Psychiatry 2015; 6:41. [PMID: 25859226 PMCID: PMC4373509 DOI: 10.3389/fpsyt.2015.00041] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 03/06/2015] [Indexed: 12/22/2022] Open
Abstract
Several lines of evidence have shown that the endogenous cannabinoids are implicated in several neuropsychiatric diseases. Notably, preclinical and human clinical studies have shown a pivotal role of the cannabinoid system in nicotine addiction. The CB1 receptor inverse agonist/antagonist rimonabant (also known as SR141716) was effective to decrease nicotine-taking and nicotine-seeking in rodents, as well as the elevation of dopamine induced by nicotine in brain reward area. Rimonabant has been shown to improve the ability of smokers to quit smoking in randomized clinical trials. However, rimonabant was removed from the market due to increased risk of psychiatric side-effects observed in humans. Recently, other components of the endogenous cannabinoid system have been explored. Here, we present the recent advances on the understanding of the role of the different components of the cannabinoid system on nicotine's effects. Those recent findings suggest possible alternative ways of modulating the cannabinoid system that could have implication for nicotine dependence treatment.
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Affiliation(s)
- Islam Hany Gamaleddin
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health , Toronto, ON , Canada ; Directorate of Poison Control and Forensic Chemistry, Ministry of Health , Riyadh , Saudi Arabia
| | - Jose M Trigo
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health , Toronto, ON , Canada
| | - Aliou B Gueye
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health , Toronto, ON , Canada
| | - Alexander Zvonok
- Center for Drug Discovery, Bouvé College of Health Sciences, Northeastern University , Boston, MA , USA
| | - Alexandros Makriyannis
- Center for Drug Discovery, Bouvé College of Health Sciences, Northeastern University , Boston, MA , USA
| | - Steven R Goldberg
- Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services , Baltimore, MD , USA
| | - Bernard Le Foll
- Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health , Toronto, ON , Canada ; Alcohol Research and Treatment Clinic, Addiction Medicine Services, Ambulatory Care and Structured Treatments, Centre for Addiction and Mental Health , Toronto, ON , Canada ; Department of Family and Community Medicine, Institute of Medical Sciences, University of Toronto , Toronto, ON , Canada ; Department of Psychiatry, Institute of Medical Sciences, University of Toronto , Toronto, ON , Canada ; Department of Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto , Toronto, ON , Canada
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Hu SSJ, Ho YC, Chiou LC. No more pain upon Gq-protein-coupled receptor activation: role of endocannabinoids. Eur J Neurosci 2014; 39:467-84. [PMID: 24494686 DOI: 10.1111/ejn.12475] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 01/24/2023]
Abstract
Marijuana has been used to relieve pain for centuries. The analgesic mechanism of its constituents, the cannabinoids, was only revealed after the discovery of cannabinoid receptors (CB1 and CB2) two decades ago. The subsequent identification of the endocannabinoids, anandamide and 2-arachidonoylglycerol (2-AG), and their biosynthetic and degradation enzymes discloses the therapeutic potential of compounds targeting the endocannabinoid system for pain control. Inhibitors of the anandamide and 2-AG degradation enzymes, fatty acid amide hydrolase and monoacylglycerol lipase, respectively, may be superior to direct cannabinoid receptor ligands as endocannabinoids are synthesized on demand and rapidly degraded, focusing action at generating sites. Recently, a promising strategy for pain relief was revealed in the periaqueductal gray (PAG). It is initiated by Gq-protein-coupled receptor (Gq PCR) activation of the phospholipase C-diacylglycerol lipase enzymatic cascade, generating 2-AG that produces inhibition of GABAergic transmission (disinhibition) in the PAG, thereby leading to analgesia. Here, we introduce the antinociceptive properties of exogenous cannabinoids and endocannabinoids, involving their biosynthesis and degradation processes, particularly in the PAG. We also review recent studies disclosing the Gq PCR-phospholipase C-diacylglycerol lipase-2-AG retrograde disinhibition mechanism in the PAG, induced by activating several Gq PCRs, including metabotropic glutamatergic (type 5 metabotropic glutamate receptor), muscarinic acetylcholine (M1/M3), and orexin 1 receptors. Disinhibition mediated by type 5 metabotropic glutamate receptor can be initiated by glutamate transporter inhibitors or indirectly by substance P, neurotensin, cholecystokinin and capsaicin. Finally, the putative role of 2-AG generated after activating the above neurotransmitter receptors in stress-induced analgesia is discussed.
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Affiliation(s)
- Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
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38
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Rivera P, Arrabal S, Cifuentes M, Grondona JM, Pérez-Martín M, Rubio L, Vargas A, Serrano A, Pavón FJ, Suárez J, Rodríguez de Fonseca F. Localization of the cannabinoid CB1 receptor and the 2-AG synthesizing (DAGLα) and degrading (MAGL, FAAH) enzymes in cells expressing the Ca(2+)-binding proteins calbindin, calretinin, and parvalbumin in the adult rat hippocampus. Front Neuroanat 2014; 8:56. [PMID: 25018703 PMCID: PMC4073216 DOI: 10.3389/fnana.2014.00056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 06/11/2014] [Indexed: 01/31/2023] Open
Abstract
The retrograde suppression of the synaptic transmission by the endocannabinoid sn-2-arachidonoylglycerol (2-AG) is mediated by the cannabinoid CB1 receptors and requires the elevation of intracellular Ca2+ and the activation of specific 2-AG synthesizing (i.e., DAGLα) enzymes. However, the anatomical organization of the neuronal substrates that express 2-AG/CB1 signaling system-related molecules associated with selective Ca2+-binding proteins (CaBPs) is still unknown. For this purpose, we used double-label immunofluorescence and confocal laser scanning microscopy for the characterization of the expression of the 2-AG/CB1 signaling system (CB1 receptor, DAGLα, MAGL, and FAAH) and the CaBPs calbindin D28k, calretinin, and parvalbumin in the rat hippocampus. CB1, DAGLα, and MAGL labeling was mainly localized in fibers and neuropil, which were differentially organized depending on the hippocampal CaBPs-expressing cells. CB+1 fiber terminals localized in all hippocampal principal cell layers were tightly attached to calbindin+ cells (granular and pyramidal neurons), and calretinin+ and parvalbumin+ interneurons. DAGLα neuropil labeling was selectively found surrounding calbindin+ principal cells in the dentate gyrus and CA1, and in the calretinin+ and parvalbumin+ interneurons in the pyramidal cell layers of the CA1/3 fields. MAGL+ terminals were only observed around CA1 calbindin+ pyramidal cells, CA1/3 calretinin+ interneurons and CA3 parvalbumin+ interneurons localized in the pyramidal cell layers. Interestingly, calbindin+ pyramidal cells expressed FAAH specifically in the CA1 field. The identification of anatomically related-neuronal substrates that expressed 2-AG/CB1 signaling system and selective CaBPs should be considered when analyzing the cannabinoid signaling associated with hippocampal functions.
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Affiliation(s)
- Patricia Rivera
- Laboratorio de Investigación, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga-Hospital Regional Universitario de Málaga (UGC Salud Mental) Málaga, Spain ; CIBER OBN, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación Madrid, Spain
| | - Sergio Arrabal
- Laboratorio de Investigación, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga-Hospital Regional Universitario de Málaga (UGC Salud Mental) Málaga, Spain ; CIBER OBN, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación Madrid, Spain
| | - Manuel Cifuentes
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga Málaga, Spain ; CIBER BBN, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación Madrid, Spain
| | - Jesús M Grondona
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga Málaga, Spain
| | - Margarita Pérez-Martín
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga Málaga, Spain
| | - Leticia Rubio
- Departamento de Anatomía y Medicina Legal, Facultad de Medicina, Universidad de Málaga Málaga, Spain
| | - Antonio Vargas
- Laboratorio de Investigación, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga-Hospital Regional Universitario de Málaga (UGC Salud Mental) Málaga, Spain
| | - Antonia Serrano
- Laboratorio de Investigación, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga-Hospital Regional Universitario de Málaga (UGC Salud Mental) Málaga, Spain ; CIBER OBN, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación Madrid, Spain
| | - Francisco J Pavón
- Laboratorio de Investigación, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga-Hospital Regional Universitario de Málaga (UGC Salud Mental) Málaga, Spain ; CIBER OBN, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación Madrid, Spain
| | - Juan Suárez
- Laboratorio de Investigación, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga-Hospital Regional Universitario de Málaga (UGC Salud Mental) Málaga, Spain ; CIBER OBN, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación Madrid, Spain
| | - Fernando Rodríguez de Fonseca
- Laboratorio de Investigación, Instituto de Investigación Biomédica (IBIMA), Universidad de Málaga-Hospital Regional Universitario de Málaga (UGC Salud Mental) Málaga, Spain ; CIBER OBN, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación Madrid, Spain
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Monoacylglycerol lipase inhibition blocks chronic stress-induced depressive-like behaviors via activation of mTOR signaling. Neuropsychopharmacology 2014; 39:1763-76. [PMID: 24476943 PMCID: PMC4023150 DOI: 10.1038/npp.2014.24] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 01/26/2014] [Accepted: 01/27/2014] [Indexed: 12/22/2022]
Abstract
The endocannabinoid (eCB) system regulates mood, emotion, and stress coping, and dysregulation of the eCB system is critically involved in pathophysiology of depression. The eCB ligand 2-arachidonoylglycerol (2-AG) is inactivated by monoacylglycerol lipase (MAGL). Using chronic unpredictable mild stress (CUS) as a mouse model of depression, we examined how 2-AG signaling in the hippocampus was altered in depressive-like states and how this alteration contributed to depressive-like behavior. We report that CUS led to impairment of depolarization-induced suppression of inhibition (DSI) in mouse hippocampal CA1 pyramidal neurons, and this deficiency in 2-AG-mediated retrograde synaptic depression was rescued by MAGL inhibitor JZL184. CUS induced depressive-like behaviors and decreased mammalian target of rapamycin (mTOR) activation in the hippocampus, and these biochemical and behavioral abnormalities were ameliorated by chronic JZL184 treatments. The effects of JZL184 were mediated by cannabinoid CB1 receptors. Genetic deletion of mTOR with adeno-associated viral (AAV) vector carrying the Cre recombinase in the hippocampus of mTORf/f mice recapitulated depressive-like behaviors induced by CUS and abrogated the antidepressant-like effects of chronic JZL184 treatments. Our results suggest that CUS decreases eCB-mTOR signaling in the hippocampus, leading to depressive-like behaviors, whereas MAGL inhibitor JZL184 produces antidepressant-like effects through enhancement of eCB-mTOR signaling.
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Hillard CJ. Stress regulates endocannabinoid-CB1 receptor signaling. Semin Immunol 2014; 26:380-8. [PMID: 24882055 DOI: 10.1016/j.smim.2014.04.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 04/01/2014] [Indexed: 12/17/2022]
Abstract
The CB1 cannabinoid receptor is a G protein coupled receptor that is widely expressed throughout the brain. The endogenous ligands for the CB1 receptor (endocannabinoids) are N-arachidonylethanolamine and 2-arachidonoylglycerol; together the endocannabinoids and CB1R subserve activity dependent, retrograde inhibition of neurotransmitter release in the brain. Deficiency of CB1 receptor signaling is associated with anhedonia, anxiety, and persistence of negative memories. CB1 receptor-endocannabinoid signaling is activated by stress and functions to buffer or dampen the behavioral and endocrine effects of acute stress. Its role in regulation of neuronal responses is more complex. Chronic variable stress exposure reduces endocannabinoid-CB1 receptor signaling and it is hypothesized that the resultant deficiency in endocannabinoid signaling contributes to the negative consequences of chronic stress. On the other hand, repeated exposure to the same stress can sensitize CB1 receptor signaling, resulting in dampening of the stress response. Data are reviewed that support the hypothesis that CB1 receptor signaling is stress responsive and that maintaining robust endocannabinoid/CB1 receptor signaling provides resilience against the development of stress-related pathologies.
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Affiliation(s)
- Cecilia J Hillard
- Neuroscience Research Center, Medical College of Wisconsin, United States; Department of Pharmacology and Toxicology, Medical College of Wisconsin, United States.
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Liedhegner ES, Vogt CD, Sem DS, Cunningham CW, Hillard CJ. Sterol carrier protein-2: binding protein for endocannabinoids. Mol Neurobiol 2014; 50:149-58. [PMID: 24510313 DOI: 10.1007/s12035-014-8651-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/23/2014] [Indexed: 12/13/2022]
Abstract
The endocannabinoid (eCB) system, consisting of eCB ligands and the type 1 cannabinoid receptor (CB1R), subserves retrograde, activity-dependent synaptic plasticity in the brain. eCB signaling occurs "on-demand," thus the processes regulating synthesis, mobilization and degradation of eCBs are also primary mechanisms for the regulation of CB1R activity. The eCBs, N-arachidonylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG), are poorly soluble in water. We hypothesize that their aqueous solubility, and, therefore, their intracellular and transcellular distribution, are facilitated by protein binding. Using in silico docking studies, we have identified the nonspecific lipid binding protein, sterol carrier protein 2 (SCP-2), as a potential AEA binding protein. The docking studies predict that AEA and AM404 associate with SCP-2 at a putative cholesterol binding pocket with ∆G values of -3.6 and -4.6 kcal/mol, respectively. These values are considerably higher than cholesterol (-6.62 kcal/mol) but consistent with a favorable binding interaction. In support of the docking studies, SCP-2-mediated transfer of cholesterol in vitro is inhibited by micromolar concentrations of AEA; and heterologous expression of SCP-2 in HEK 293 cells increases time-related accumulation of AEA in a temperature-dependent fashion. These results suggest that SCP-2 facilitates cellular uptake of AEA. However, there is no effect of SCP-2 transfection on the cellular accumulation of AEA determined at equilibrium or the IC50 values for AEA, AM404 or 2-AG to inhibit steady state accumulation of radiolabelled AEA. We conclude that SCP-2 is a low affinity binding protein for AEA that can facilitate its cellular uptake but does not contribute significantly to intracellular sequestration of AEA.
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Affiliation(s)
- Elizabeth Sabens Liedhegner
- Neuroscience Research Center and Departments of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
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Sharkey KA, Darmani NA, Parker LA. Regulation of nausea and vomiting by cannabinoids and the endocannabinoid system. Eur J Pharmacol 2014; 722:134-46. [PMID: 24184696 PMCID: PMC3883513 DOI: 10.1016/j.ejphar.2013.09.068] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 09/22/2013] [Accepted: 09/27/2013] [Indexed: 12/13/2022]
Abstract
Nausea and vomiting (emesis) are important elements in defensive or protective responses that animals use to avoid ingestion or digestion of potentially harmful substances. However, these neurally-mediated responses are at times manifested as symptoms of disease and they are frequently observed as side-effects of a variety of medications, notably those used to treat cancer. Cannabis has long been known to limit or prevent nausea and vomiting from a variety of causes. This has led to extensive investigations that have revealed an important role for cannabinoids and their receptors in the regulation of nausea and emesis. With the discovery of the endocannabinoid system, novel ways to regulate both nausea and vomiting have been discovered that involve the production of endogenous cannabinoids acting centrally. Here we review recent progress in understanding the regulation of nausea and vomiting by cannabinoids and the endocannabinoid system, and we discuss the potential to utilize the endocannabinoid system in the treatment of these frequently debilitating conditions.
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Affiliation(s)
- Keith A Sharkey
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada T2N 4N1.
| | - Nissar A Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, USA
| | - Linda A Parker
- Department of Psychology, University of Guelph, Guelph, ON, Canada
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Chiou LC, Hu SSJ, Ho YC. Targeting the cannabinoid system for pain relief? ACTA ACUST UNITED AC 2013; 51:161-70. [PMID: 24529672 DOI: 10.1016/j.aat.2013.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/11/2013] [Indexed: 12/15/2022]
Abstract
Marijuana has been used to relieve pain for centuries, but its analgesic mechanism has only been understood during the past two decades. It is mainly mediated by its constituents, cannabinoids, through activating central cannabinoid 1 (CB1) receptors, as well as peripheral CB1 and CB2 receptors. CB2-selective agonists have the benefit of lacking CB1 receptor-mediated CNS side effects. Anandamide and 2-arachidonoylglycerol (2-AG) are two intensively studied endogenous lipid ligands of cannabinoid receptors, termed endocannabinoids, which are synthesized on demand and rapidly degraded. Thus, inhibitors of their degradation enzymes, fatty acid amide hydrolase and monoacylglycerol lipase (MAGL), respectively, may be superior to direct cannabinoid receptor ligands as a promising strategy for pain relief. In addition to the antinociceptive properties of exogenous cannabinoids and endocannabinoids, involving their biosynthesis and degradation processes, we also review recent studies that revealed a novel analgesic mechanism, involving 2-AG in the periaqueductal gray (PAG), a midbrain region for initiating descending pain inhibition. It is initiated by Gq-protein-coupled receptor (GqPCR) activation of the phospholipase C (PLC)-diacylglycerol lipase (DAGL) enzymatic cascade, generating 2-AG that produces inhibition of GABAergic transmission (disinhibition) in the PAG, thereby leading to analgesia. This GqPCR-PLC-DAGL-2-AG retrograde disinhibition mechanism in the PAG can be initiated by activating type 5 metabotropic glutamate receptor (mGluR5), muscarinic acetylcholine (M1/M3), and orexin (OX1) receptors. mGluR5-mediated disinhibition can be initiated by glutamate transporter inhibitors, or indirectly by substance P, neurotensin, cholecystokinin, capsaicin, and AM404, the bioactive metabolite of acetaminophen in the brain. The putative role of 2-AG generated after activating the above neurotransmitter receptors in stress-induced analgesia is also discussed.
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Affiliation(s)
- Lih-Chu Chiou
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Pharmacology, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan; Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan.
| | - Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Cheng Ho
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Liedhegner ES, Sasman A, Hillard CJ. Brain region-specific changes in N-acylethanolamine contents with time of day. J Neurochem 2013; 128:491-506. [PMID: 24138639 DOI: 10.1111/jnc.12495] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 09/06/2013] [Accepted: 10/04/2013] [Indexed: 11/28/2022]
Abstract
The N-acylethanolamines (NAEs) exert important behavioral, physiological, and immunological effects through actions at cannabinoid and other receptors. We measured concentrations of three NAEs, the Km and Vmax for fatty acid amide hydrolysis (FAAH), FAAH protein and FAAH mRNA in prefrontal cortex, hippocampus, hypothalamus, amygdala, striatum, and cerebellum at 4 h intervals, starting at 03:00. Significant differences in N-arachidonylethanolamine contents among the times examined occur in the prefrontal cortex (PFC), hippocampus, hypothalamus, and striatum. N-Oleoylethanolamine concentrations exhibit large fluctuations over the day in the cerebellum, including a threefold decrease between 19:00 and 23:00. N-Palmitoylethanolamine and N-oleoylethanolamine were significantly, positively correlated in all regions examined except the hypothalamus. FAAH Km values are significantly affected by time of day in PFC, hippocampus and amygdala and FAAH Vmax values are significantly affected in PFC, hippocampus and cerebellum. However, correlational data indicate that FAAH does not play a primary role in the circadian regulation of the NAE concentrations. FAAH protein expression is not significantly different among the harvest times in any brain region examined. Concentrations of 2-arachidonoylglycerol are significantly affected by time of harvest in the striatum and cerebellum, but not in other brain regions. Together, these data indicate that the NAEs exhibit diverse patterns of change with time of day that are likely the result of alterations in biosynthesis, and support the hypothesis that N-arachidonylethanolamine is a tonic activator of cannabinoid receptor signaling.
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Affiliation(s)
- Elizabeth Sabens Liedhegner
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Role of FAAH-like anandamide transporter in anandamide inactivation. PLoS One 2013; 8:e79355. [PMID: 24223930 PMCID: PMC3817039 DOI: 10.1371/journal.pone.0079355] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/30/2013] [Indexed: 11/19/2022] Open
Abstract
The endocannabinoid system modulates numerous physiological processes including nociception and reproduction. Anandamide (AEA) is an endocannabinoid that is inactivated by cellular uptake followed by intracellular hydrolysis by fatty acid amide hydrolase (FAAH). Recently, FAAH-like anandamide transporter (FLAT), a truncated and catalytically-inactive variant of FAAH, was proposed to function as an intracellular AEA carrier and mediate its delivery to FAAH for hydrolysis. Pharmacological inhibition of FLAT potentiated AEA signaling and produced antinociceptive effects. Given that endocannabinoids produce analgesia through central and peripheral mechanisms, the goal of the current work was to examine the expression of FLAT in the central and peripheral nervous systems. In contrast to the original report characterizing FLAT, expression of FLAT was not observed in any of the tissues examined. To investigate the role of FLAT as a putative AEA binding protein, FLAT was generated from FAAH using polymerase chain reaction and further analyzed. Despite its low cellular expression, FLAT displayed residual catalytic activity that was sensitive to FAAH inhibitors and abolished following mutation of its catalytic serine. Overexpression of FLAT potentiated AEA cellular uptake and this appeared to be dependent upon its catalytic activity. Immunofluorescence revealed that FLAT localizes primarily to intracellular membranes and does not contact the plasma membrane, suggesting that its capability to potentiate AEA uptake may stem from its enzymatic rather than transport activity. Collectively, our data demonstrate that FLAT does not serve as a global intracellular AEA carrier, although a role in mediating localized AEA inactivation in mammalian tissues cannot be ruled out.
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Amygdala FAAH and anandamide: mediating protection and recovery from stress. Trends Pharmacol Sci 2013; 34:637-44. [PMID: 24325918 DOI: 10.1016/j.tips.2013.08.008] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 08/27/2013] [Accepted: 08/29/2013] [Indexed: 11/23/2022]
Abstract
A long-standing literature linking endocannabinoids (ECBs) to stress, fear, and anxiety has led to growing interest in developing novel anxiolytics targeting the ECB system. Following rapid on-demand biosynthesis and degradation upon neuronal activation, the ECB N-arachidonoylethanolamide (anandamide, AEA) is actively degraded by the serine hydrolase enzyme, fatty acid amide hydrolase (FAAH). Exposure to stress rapidly mobilizes FAAH to deplete the signaling pool of AEA and increase neuronal excitability in a key anxiety-mediating region--the basolateral amygdala (BLA). Gene deletion or pharmacological inhibition of FAAH prevents stress-induced reductions in AEA and associated increases in BLA dendritic hypertrophy and anxiety-like behavior. Additionally, inhibition of FAAH facilitates long-term fear extinction and rescues deficient fear extinction in rodent models by enhancing AEA-CB1 (cannabinoid type 1) receptor signaling and synaptic plasticity in the BLA. These preclinical findings propose restoring deficient BLA AEA levels by pharmacologically inhibiting FAAH as a mechanism to therapeutically mitigate the effects of traumatic stress.
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Mathur BN, Tanahira C, Tamamaki N, Lovinger DM. Voltage drives diverse endocannabinoid signals to mediate striatal microcircuit-specific plasticity. Nat Neurosci 2013; 16:1275-83. [PMID: 23892554 PMCID: PMC3758434 DOI: 10.1038/nn.3478] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/20/2013] [Indexed: 11/09/2022]
Abstract
The dorsolateral striatum and cannabinoid type 1 receptor (CB1) signaling mediate habitual action learning, which is thought to require a balance of activity in the direct and indirect striatal output pathways. However, very little is known about how the high CB1-expressing striatal inhibitory microcircuitry might contribute to long-term plasticity capable of sculpting direct/indirect pathway output. Using optogenetic and molecular interrogation of striatal GABAergic microcircuits, we describe novel mechanisms of voltage-dependent long-term depression of inhibitory synapses (iLTD) onto mouse and rat medium spiny projection neurons (MSNs). This iLTD involves recruitment of different endocannabinoid types and shows both presynaptic and postsynaptic selectivity for MSN subtypes, ultimately resulting in a powerful disinhibition of direct pathway MSNs. These results indicate a new role for voltage states in gating circuit-specific forms of synaptic plasticity and illuminate possible circuit dynamics underlying action control.
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Affiliation(s)
- Brian N Mathur
- Section on Synaptic Pharmacology, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, US National Institutes of Health, Bethesda, Maryland, USA
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Starowicz K, Przewlocka B. Modulation of neuropathic-pain-related behaviour by the spinal endocannabinoid/endovanilloid system. Philos Trans R Soc Lond B Biol Sci 2013; 367:3286-99. [PMID: 23108547 DOI: 10.1098/rstb.2011.0392] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neuropathic pain refers to chronic pain that results from injury to the nervous system. The mechanisms involved in neuropathic pain are complex and involve both peripheral and central phenomena. Although numerous pharmacological agents are available for the treatment of neuropathic pain, definitive drug therapy has remained elusive. Recent drug discovery efforts have identified an original neurobiological approach to the pathophysiology of neuropathic pain. The development of innovative pharmacological strategies has led to the identification of new promising pharmacological targets, including glutamate antagonists, microglia inhibitors and, interestingly, endogenous ligands of cannabinoids and the transient receptor potential vanilloid type 1 (TRPV1). Endocannabinoids (ECs), endovanilloids and the enzymes that regulate their metabolism represent promising pharmacological targets for the development of a successful pain treatment. This review is an update of the relationship between cannabinoid receptors (CB1) and TRPV1 channels and their possible implications for neuropathic pain. The data are focused on endogenous spinal mechanisms of pain control by anandamide, and the current and emerging pharmacotherapeutic approaches that benefit from the pharmacological modulation of spinal EC and/or endovanilloid systems under chronic pain conditions will be discussed.
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Affiliation(s)
- Katarzyna Starowicz
- Department of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, ul. Smetna 12, 31-343 Krakow, Poland.
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49
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Endogenous cannabinoids revisited: A biochemistry perspective. Prostaglandins Other Lipid Mediat 2013; 102-103:13-30. [DOI: 10.1016/j.prostaglandins.2013.02.002] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 12/13/2022]
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50
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