101
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Di Marzo V, Stella N, Zimmer A. Endocannabinoid signalling and the deteriorating brain. Nat Rev Neurosci 2015; 16:30-42. [PMID: 25524120 DOI: 10.1038/nrn3876] [Citation(s) in RCA: 266] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ageing is characterized by the progressive impairment of physiological functions and increased risk of developing debilitating disorders, including chronic inflammation and neurodegenerative diseases. These disorders have common molecular mechanisms that can be targeted therapeutically. In the wake of the approval of the first cannabinoid-based drug for the symptomatic treatment of multiple sclerosis, we examine how endocannabinoid (eCB) signalling controls--and is affected by--normal ageing and neuroinflammatory and neurodegenerative disorders. We propose a conceptual framework linking eCB signalling to the control of the cellular and molecular hallmarks of these processes, and categorize the key components of endocannabinoid signalling that may serve as targets for novel therapeutics.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Naples, Italy
| | - Nephi Stella
- 1] Department of Pharmacology, University of Washington. [2] Department of Psychiatry and Behavioral Science, University of Washington, 1959 Pacific Avenue North, Seattle, Washington 98103, USA
| | - Andreas Zimmer
- Institute for Molecular Psychiatry, University of Bonn, Sigmund Freud Straße 25, Bonn 53127, Germany
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102
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Pascual A, Martín-Moreno A, Giusto N, de Ceballos M, Pasquaré S. Normal aging in rats and pathological aging in human Alzheimer’s disease decrease FAAH activity: Modulation by cannabinoid agonists. Exp Gerontol 2014; 60:92-9. [DOI: 10.1016/j.exger.2014.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 10/15/2014] [Accepted: 10/16/2014] [Indexed: 12/21/2022]
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103
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The endocannabinoid 2-AG controls skeletal muscle cell differentiation via CB1 receptor-dependent inhibition of Kv7 channels. Proc Natl Acad Sci U S A 2014; 111:E2472-81. [PMID: 24927567 DOI: 10.1073/pnas.1406728111] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Little is known of the involvement of endocannabinoids and cannabinoid receptors in skeletal muscle cell differentiation. We report that, due to changes in the expression of genes involved in its metabolism, the levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) are decreased both during myotube formation in vitro from murine C2C12 myoblasts and during mouse muscle growth in vivo. The endocannabinoid, as well as the CB1 agonist arachidonoyl-2-chloroethylamide, prevent myotube formation in a manner antagonized by CB1 knockdown and by CB1 antagonists, which, per se, instead stimulate differentiation. Importantly, 2-AG also inhibits differentiation of primary human satellite cells. Muscle fascicles from CB1 knockout embryos contain more muscle fibers, and postnatal mice show muscle fibers of an increased diameter relative to wild-type littermates. Inhibition of Kv7.4 channel activity, which plays a permissive role in myogenesis and depends on phosphatidylinositol 4,5-bisphosphate (PIP2), underlies the effects of 2-AG. We find that CB1 stimulation reduces both total and Kv7.4-bound PIP2 levels in C2C12 cells and inhibits Kv7.4 currents in transfected CHO cells. We suggest that 2-AG is an endogenous repressor of myoblast differentiation via CB1-mediated inhibition of Kv7.4 channels.
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104
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Enrichment of phosphatidylinositols with specific acyl chains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1501-8. [DOI: 10.1016/j.bbamem.2013.10.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 09/25/2013] [Accepted: 10/03/2013] [Indexed: 12/21/2022]
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105
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Pascual AC, Gaveglio VL, Giusto NM, Pasquaré SJ. Cannabinoid receptor-dependent metabolism of 2-arachidonoylglycerol during aging. Exp Gerontol 2014; 55:134-42. [PMID: 24768821 DOI: 10.1016/j.exger.2014.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/27/2014] [Accepted: 04/16/2014] [Indexed: 01/23/2023]
Abstract
2-Arachidonoylglycerol (2-AG) is one of the principal endocannabinoids involved in the protection against neurodegenerative processes. Cannabinoids primarily interact with the seven-segment transmembrane cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), both of which are expressed in the central nervous system (CNS). The level of 2-AG is controlled through key enzymes responsible for its synthesis or degradation. We have previously observed a deregulation of 2-AG metabolism in physiological aging. The aim of this study was to analyze how 2-AG metabolism is modulated by CB1/CB2 receptors during aging. To this end, both CB1 and CB2 receptor expression and the enzymatic activities (diacylglycerol lipase (DAGL), lysophosphatidate phosphohydrolase (LPAase) and monoacylglycerol lipase (MAGL)) involved in 2-AG metabolism were analyzed in the presence of cannabinoid receptor (CBR) agonists (WIN and JWH) and/or antagonists (SR1 and SR2) in synaptosomes from adult and aged rat cerebral cortex (CC). Our results demonstrate that: (a) aging decreases the expression of both CBRs; (b) LPAase inhibition, due to the individual action of SR1 or SR2, is reverted in the presence of both antagonists together; (c) LPAase activity is regulated mainly by the CB1 receptor in adult and in aged synaptosomes while the CB2 receptor acquires importance when CB1 is blocked; (d) modulation via CBRs of DAGL and MAGL by both antagonists occurs only in aged synaptosomes, stimulating DAGL and inhibiting MAGL activities; (e) only DAGL stimulation is reverted by WIN. Taken together, the results of the present study show that CB1 and/or CB2 receptor antagonists trigger a significant modulation of 2-AG metabolism, underlining their relevance as therapeutic strategy for controlling endocannabinoid levels in physiological aging.
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MESH Headings
- Aging/metabolism
- Animals
- Arachidonic Acids/metabolism
- Cell Membrane/metabolism
- Cerebral Cortex/metabolism
- Endocannabinoids/metabolism
- Glycerides/metabolism
- Lipoprotein Lipase/metabolism
- Monoacylglycerol Lipases/metabolism
- Phosphatidate Phosphatase/metabolism
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/metabolism
- Receptors, Cannabinoid/metabolism
- Receptors, Cannabinoid/physiology
- Synaptosomes/metabolism
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Affiliation(s)
- Ana C Pascual
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Edificio E1. Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Virginia L Gaveglio
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Edificio E1. Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Norma M Giusto
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Edificio E1. Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Susana J Pasquaré
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Edificio E1. Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina.
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106
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Aso E, Ferrer I. Cannabinoids for treatment of Alzheimer's disease: moving toward the clinic. Front Pharmacol 2014; 5:37. [PMID: 24634659 PMCID: PMC3942876 DOI: 10.3389/fphar.2014.00037] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 02/19/2014] [Indexed: 01/17/2023] Open
Abstract
The limited effectiveness of current therapies against Alzheimer’s disease (AD) highlights the need for intensifying research efforts devoted to developing new agents for preventing or retarding the disease process. During the last few years, targeting the endogenous cannabinoid system has emerged as a potential therapeutic approach to treat Alzheimer. The endocannabinoid system is composed by a number of cannabinoid receptors, including the well-characterized CB1 and CB2 receptors, with their endogenous ligands and the enzymes related to the synthesis and degradation of these endocannabinoid compounds. Several findings indicate that the activation of both CB1 and CB2 receptors by natural or synthetic agonists, at non-psychoactive doses, have beneficial effects in Alzheimer experimental models by reducing the harmful β-amyloid peptide action and tau phosphorylation, as well as by promoting the brain’s intrinsic repair mechanisms. Moreover, endocannabinoid signaling has been demonstrated to modulate numerous concomitant pathological processes, including neuroinflammation, excitotoxicity, mitochondrial dysfunction, and oxidative stress. The present paper summarizes the main experimental studies demonstrating the polyvalent properties of cannabinoid compounds for the treatment of AD, which together encourage progress toward a clinical trial.
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Affiliation(s)
- Ester Aso
- Institut de Neuropatologia, Servei d'Anatomia Patològica, Institut d'Investigació Biomèdica de Bellvitge-Hospital Universitari de Bellvitge, Universitat de Barcelona, L'Hospitalet de Llobregat Spain ; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto Carlos III Spain
| | - Isidre Ferrer
- Institut de Neuropatologia, Servei d'Anatomia Patològica, Institut d'Investigació Biomèdica de Bellvitge-Hospital Universitari de Bellvitge, Universitat de Barcelona, L'Hospitalet de Llobregat Spain ; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto Carlos III Spain
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107
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Fagan SG, Campbell VA. The influence of cannabinoids on generic traits of neurodegeneration. Br J Pharmacol 2014; 171:1347-60. [PMID: 24172185 PMCID: PMC3954477 DOI: 10.1111/bph.12492] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 09/14/2013] [Accepted: 09/16/2013] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED In an increasingly ageing population, the incidence of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and Huntington's disease are rising. While the aetiologies of these disorders are different, a number of common mechanisms that underlie their neurodegenerative components have been elucidated; namely neuroinflammation, excitotoxicity, mitochondrial dysfunction and reduced trophic support. Current therapies focus on treatment of the symptoms and attempt to delay the progression of these diseases but there is currently no cure. Modulation of the endogenous cannabinoid system is emerging as a potentially viable option in the treatment of neurodegeneration. Endocannabinoid signalling has been found to be altered in many neurodegenerative disorders. To this end, pharmacological manipulation of the endogenous cannabinoid system, as well as application of phytocannabinoids and synthetic cannabinoids have been investigated. Signalling from the CB1 and CB2 receptors are known to be involved in the regulation of Ca(2+) homeostasis, mitochondrial function, trophic support and inflammatory status, respectively, while other receptors gated by cannabinoids such as PPARγ, are gaining interest in their anti-inflammatory properties. Through multiple lines of evidence, this evolutionarily conserved neurosignalling system has shown neuroprotective capabilities and is therefore a potential target for neurodegenerative disorders. This review details the mechanisms of neurodegeneration and highlights the beneficial effects of cannabinoid treatment. LINKED ARTICLES This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6.
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Affiliation(s)
- S G Fagan
- Trinity College Institute of Neuroscience, Department of Physiology, School of Medicine, University of Dublin, Trinity CollegeDublin 2, Ireland
| | - V A Campbell
- Trinity College Institute of Neuroscience, Department of Physiology, School of Medicine, University of Dublin, Trinity CollegeDublin 2, Ireland
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108
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Tortoriello G, Morris CV, Alpar A, Fuzik J, Shirran SL, Calvigioni D, Keimpema E, Botting CH, Reinecke K, Herdegen T, Courtney M, Hurd YL, Harkany T. Miswiring the brain: Δ9-tetrahydrocannabinol disrupts cortical development by inducing an SCG10/stathmin-2 degradation pathway. EMBO J 2014; 33:668-85. [PMID: 24469251 DOI: 10.1002/embj.201386035] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Children exposed in utero to cannabis present permanent neurobehavioral and cognitive impairments. Psychoactive constituents from Cannabis spp., particularly Δ(9)-tetrahydrocannabinol (THC), bind to cannabinoid receptors in the fetal brain. However, it is unknown whether THC can trigger a cannabinoid receptor-driven molecular cascade to disrupt neuronal specification. Here, we show that repeated THC exposure disrupts endocannabinoid signaling, particularly the temporal dynamics of CB1 cannabinoid receptor, to rewire the fetal cortical circuitry. By interrogating the THC-sensitive neuronal proteome we identify Superior Cervical Ganglion 10 (SCG10)/stathmin-2, a microtubule-binding protein in axons, as a substrate of altered neuronal connectivity. We find SCG10 mRNA and protein reduced in the hippocampus of midgestational human cannabis-exposed fetuses, defining SCG10 as the first cannabis-driven molecular effector in the developing cerebrum. CB1 cannabinoid receptor activation recruits c-Jun N-terminal kinases to phosphorylate SCG10, promoting its rapid degradation in situ in motile axons and microtubule stabilization. Thus, THC enables ectopic formation of filopodia and alters axon morphology. These data highlight the maintenance of cytoskeletal dynamics as a molecular target for cannabis, whose imbalance can limit the computational power of neuronal circuitries in affected offspring.
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Affiliation(s)
- Giuseppe Tortoriello
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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109
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Neuregulin-1 impairs the long-term depression of hippocampal inhibitory synapses by facilitating the degradation of endocannabinoid 2-AG. J Neurosci 2013; 33:15022-31. [PMID: 24048832 DOI: 10.1523/jneurosci.5833-12.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Endocannabinoids play essential roles in synaptic plasticity; thus, their dysfunction often causes impairments in memory or cognition. However, it is not well understood whether deficits in the endocannabinoid system account for the cognitive symptoms of schizophrenia. Here, we show that endocannabinoid-mediated synaptic regulation is impaired by the prolonged elevation of neuregulin-1, the abnormality of which is a hallmark in many patients with schizophrenia. When rat hippocampal slices were chronically treated with neuregulin-1, the degradation of 2-arachidonoylglycerol (2-AG), one of the major endocannabinoids, was enhanced due to the increased expression of its degradative enzyme, monoacylglycerol lipase. As a result, the time course of depolarization-induced 2-AG signaling was shortened, and the magnitude of 2-AG-dependent long-term depression of inhibitory synapses was reduced. Our study reveals that an alteration in the signaling of 2-AG contributes to hippocampal synaptic dysfunction in a hyper-neuregulin-1 condition and thus provides novel insights into potential schizophrenic therapeutics that target the endocannabinoid system.
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110
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Malenczyk K, Jazurek M, Keimpema E, Silvestri C, Janikiewicz J, Mackie K, Di Marzo V, Redowicz MJ, Harkany T, Dobrzyn A. CB1 cannabinoid receptors couple to focal adhesion kinase to control insulin release. J Biol Chem 2013; 288:32685-32699. [PMID: 24089517 DOI: 10.1074/jbc.m113.478354] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Endocannabinoid signaling has been implicated in modulating insulin release from β cells of the endocrine pancreas. β Cells express CB1 cannabinoid receptors (CB1Rs), and the enzymatic machinery regulating anandamide and 2-arachidonoylglycerol bioavailability. However, the molecular cascade coupling agonist-induced cannabinoid receptor activation to insulin release remains unknown. By combining molecular pharmacology and genetic tools in INS-1E cells and in vivo, we show that CB1R activation by endocannabinoids (anandamide and 2-arachidonoylglycerol) or synthetic agonists acutely or after prolonged exposure induces insulin hypersecretion. In doing so, CB1Rs recruit Akt/PKB and extracellular signal-regulated kinases 1/2 to phosphorylate focal adhesion kinase (FAK). FAK activation induces the formation of focal adhesion plaques, multimolecular platforms for second-phase insulin release. Inhibition of endocannabinoid synthesis or FAK activity precluded insulin release. We conclude that FAK downstream from CB1Rs mediates endocannabinoid-induced insulin release by allowing cytoskeletal reorganization that is required for the exocytosis of secretory vesicles. These findings suggest a mechanistic link between increased circulating and tissue endocannabinoid levels and hyperinsulinemia in type 2 diabetes.
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Affiliation(s)
- Katarzyna Malenczyk
- From the Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland,; the Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Magdalena Jazurek
- From the Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Erik Keimpema
- the Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Cristoforo Silvestri
- the Endocannabinoid Research Group, Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli, Naples, Italy
| | | | - Ken Mackie
- the Department of Psychological and Brain Sciences, Gill Center for Neuroscience, Indiana University, Bloomington, Indiana 47405
| | - Vincenzo Di Marzo
- the Endocannabinoid Research Group, Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, I-80078 Pozzuoli, Naples, Italy
| | - Maria J Redowicz
- From the Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Tibor Harkany
- the Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, SE-17177 Stockholm, Sweden,; the School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom.
| | - Agnieszka Dobrzyn
- From the Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland,.
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111
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Trimpin S, Wang B, Lietz CB, Marshall DD, Richards AL, Inutan ED. New ionization processes and applications for use in mass spectrometry. Crit Rev Biochem Mol Biol 2013; 48:409-29. [DOI: 10.3109/10409238.2013.806887] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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112
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Cannabinoid receptor 1 deficiency in a mouse model of Alzheimer's disease leads to enhanced cognitive impairment despite of a reduction in amyloid deposition. Neurobiol Aging 2013; 34:2574-84. [PMID: 23838176 DOI: 10.1016/j.neurobiolaging.2013.05.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 05/18/2013] [Accepted: 05/27/2013] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is characterized by amyloid-β deposition in amyloid plaques, neurofibrillary tangles, inflammation, neuronal loss, and cognitive deficits. Cannabinoids display neuromodulatory and neuroprotective effects and affect memory acquisition. Here, we studied the impact of cannabinoid receptor type 1 (CB1) deficiency on the development of AD pathology by breeding amyloid precursor protein (APP) Swedish mutant mice (APP23), an AD animal model, with CB1-deficient mice. In addition to the lower body weight of APP23/CB1(-/-) mice, most of these mice died at an age before typical AD-associated changes become apparent. The surviving mice showed a reduced amount of APP and its fragments suggesting a regulatory influence of CB1 on APP processing, which was confirmed by modulating CB1 expression in vitro. Reduced APP levels were accompanied by a reduced plaque load and less inflammation in APP23/CB1(-/-) mice. Nevertheless, compared to APP23 mice with an intact CB1, APP23/CB1(-/-) mice showed impaired learning and memory deficits. These data argue against a direct correlation of amyloid plaque load with cognitive abilities in this AD mouse model lacking CB1. Furthermore, the findings indicate that CB1 deficiency can worsen AD-related cognitive deficits and support a potential role of CB1 as a pharmacologic target.
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113
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Köles L, Garção P, Zádori ZS, Ferreira SG, Pinheiro BS, da Silva-Santos CS, Ledent C, Köfalvi A. Presynaptic TRPV1 vanilloid receptor function is age- but not CB1 cannabinoid receptor-dependent in the rodent forebrain. Brain Res Bull 2013; 97:126-35. [PMID: 23831917 DOI: 10.1016/j.brainresbull.2013.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/14/2013] [Accepted: 06/27/2013] [Indexed: 02/01/2023]
Abstract
Neocortical and striatal TRPV1 (vanilloid or capsaicin) receptors (TRPV1Rs) are excitatory ligand-gated ion channels, and are implicated in psychiatric disorders. However, the purported presynaptic neuromodulator role of TRPV1Rs in glutamatergic, serotonergic or dopaminergic terminals of the rodent forebrain remains little understood. With the help of patch-clamp electrophysiology and neurochemical approaches, we mapped the age-dependence of presynaptic TRPV1R function, and furthermore, we aimed at exploring whether the presence of CB1 cannabinoid receptors (CB1Rs) influences the function of the TRPV1Rs, as both receptor types share endogenous ligands. We found that the major factor which affects presynaptic TRPV1R function is age: by post-natal day 13, the amplitude of capsaicin-induced release of dopamine and glutamate is halved in the rat striatum, and two weeks later, capsaicin already loses its effect. However, TRPV1R receptor function is not enhanced by chemical or genetic ablation of the CB1Rs in dopaminergic, glutamatergic and serotonergic terminals of the mouse brain. Altogether, our data indicate a possible neurodevelopmental role for presynaptic TRPV1Rs in the rodent brain, but we found no cross-talk between TRPV1Rs and CB1Rs in the same nerve terminal.
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Key Words
- 3Rs
- 4-AP
- 4-aminopyridine
- 7-, 14-, 29- and 60-day-old
- 7D, 14D, 29D, 60D
- ACEA
- ARC
- ARRIVE
- AUC
- American Radiolabeled Chemicals
- Animal Research: Reporting In Vivo Experiments
- BCA
- BSA
- CB(1) cannabinoid receptor
- CB(1)R
- DMSO
- DPM
- DTT
- Dopamine
- ECF
- EDTA
- EGTA
- FR%
- Federation for Laboratory Animal Science Associations
- Felasa
- GABA
- Glutamate
- HEPES
- KHR
- KO
- Krebs-HEPES-Ringer
- LiGTP
- MAO B
- MgATP
- N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid)
- N-arachidonyl dopamine
- NADA
- NO
- PMSF
- PVDF
- RTX
- SDS
- SEM
- Serotonin
- Striatum
- TBS-T
- TRPV(1) vanilloid receptor
- TRPV(1)R and TRPV(4)R
- Tris
- Tris-buffered saline with Tween 20
- WT
- aCSF
- arachidonyl-2′-chloroethylamide
- area-under-the-curve
- artificial cerebrospinal fluid
- bicinchoninic acid
- bovine serum albumin
- cannabinoid receptor type 1
- dimethyl sulfoxide
- disintegration per minute
- dithiothreitol
- enhanced chemi-fluorescence
- ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid
- ethylenediaminetetraacetic acid
- fractional release %
- knockout
- lithium guanozine triphosphate
- magnesium adenosine triphosphate
- monoamine oxidase B
- nitric oxide
- phenylmethanesulfonyl fluoride
- polyvinylidene difluoride
- replacement, reduction, refinement
- resiniferatoxin
- sEPSCs
- sodium dodecyl sulfate
- spontaneous excitatory postsynaptic currents
- standard error of the mean
- transient release potential receptor vanilloid type 4
- tris(hydroxymethyl)aminomethane
- wild-type
- γ-aminobutyric acid
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Affiliation(s)
- László Köles
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary
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114
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Bilkei-Gorzo A. The endocannabinoid system in normal and pathological brain ageing. Philos Trans R Soc Lond B Biol Sci 2013; 367:3326-41. [PMID: 23108550 DOI: 10.1098/rstb.2011.0388] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The role of endocannabinoids as inhibitory retrograde transmitters is now widely known and intensively studied. However, endocannabinoids also influence neuronal activity by exerting neuroprotective effects and regulating glial responses. This review centres around this less-studied area, focusing on the cellular and molecular mechanisms underlying the protective effect of the cannabinoid system in brain ageing. The progression of ageing is largely determined by the balance between detrimental, pro-ageing, largely stochastic processes, and the activity of the homeostatic defence system. Experimental evidence suggests that the cannabinoid system is part of the latter system. Cannabinoids as regulators of mitochondrial activity, as anti-oxidants and as modulators of clearance processes protect neurons on the molecular level. On the cellular level, the cannabinoid system regulates the expression of brain-derived neurotrophic factor and neurogenesis. Neuroinflammatory processes contributing to the progression of normal brain ageing and to the pathogenesis of neurodegenerative diseases are suppressed by cannabinoids, suggesting that they may also influence the ageing process on the system level. In good agreement with the hypothesized beneficial role of cannabinoid system activity against brain ageing, it was shown that animals lacking CB1 receptors show early onset of learning deficits associated with age-related histological and molecular changes. In preclinical models of neurodegenerative disorders, cannabinoids show beneficial effects, but the clinical evidence regarding their efficacy as therapeutic tools is either inconclusive or still missing.
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115
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Pascual AC, Gaveglio VL, Giusto NM, Pasquaré SJ. Aging modifies the enzymatic activities involved in 2-arachidonoylglycerol metabolism. Biofactors 2013; 39:209-20. [PMID: 23281018 DOI: 10.1002/biof.1055] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 09/08/2012] [Indexed: 12/17/2022]
Abstract
One of the principal monoacylglycerol (MAG) species in animal tissues is 2-arachidonoylglycerol (2-AG), and the diacylglycerol lipase (DAGL) pathway is the most important 2-AG biosynthetic pathway proposed to date. Lysophosphatidate phosphatase (LPAase) activity is part of another 2-AG-forming pathway in which monoacylglycerol lipase (MAGL) is the major degrading enzyme. The purpose of this study was to analyze the manner in which DAGL, LPAase, and MAGL enzymes are modified in the central nervous system (CNS) during aging. To this end, diacylglycerols (DAGs) and MAGs of different composition were used as substrates of DAGL and MAGL, respectively. All enzymatic activities were evaluated in membrane and soluble fractions as well as in synaptic terminals from the cerebral cortex (CC) of adult and aged rats. Results related to 2-AG metabolism show that aging: (a) decreases DAGL-α expression in the membrane fraction whereas in synaptosomes it increases DAGL-β and decreases MAGL expression; (b) decreases LPAase activity in both membrane and soluble fractions; (c) decreases DAGL and stimulates LPAase activities in CC synaptic terminals; (d) stimulates membrane-associated MAGL-coupled DAGL activity; and (e) stimulates MAGL activity in CC synaptosomes. Our results also reveal that during aging the net balance between the enzymatic activities involved in 2-AG synthesis and breakdown is low availability of 2-AG in CC membrane fractions and synaptic terminals. Taken together, our results lead us to conclude that these enzymes play crucial roles in the regulation of 2-AG tissue levels during aging.
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Affiliation(s)
- Ana C Pascual
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000 Bahía Blanca, Argentina
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Neurochemical mapping of the human hippocampus reveals perisynaptic matrix around functional synapses in Alzheimer's disease. Acta Neuropathol 2013; 125:215-29. [PMID: 22961619 DOI: 10.1007/s00401-012-1042-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/24/2012] [Accepted: 08/27/2012] [Indexed: 12/16/2022]
Abstract
Perineuronal matrix is an extracellular protein scaffold to shape neuronal responsiveness and survival. Whilst perineuronal nets engulf the somatodendritic axis of neurons, axonal coats are focal extracellular protein aggregates surrounding individual synapses. Here, we addressed the chemical identity and subcellular localization of both perineuronal and perisynaptic matrices in the human hippocampus, whose neuronal circuitry is progressively compromised in Alzheimer's disease. We hypothesized that (1) the cellular expression sites of chondroitin sulphate proteoglycan-containing extracellular matrix associate with specific neuronal identities, reflecting network dynamics, and (2) the regional distribution and molecular composition of axonal coats must withstand Alzheimer's disease-related modifications to protect functional synapses. We show by epitope-specific antibodies that the perineuronal protomap of the human hippocampus is distinct from other mammals since pyramidal cells but not calretinin(+) and calbindin(+) interneurons, neurochemically classified as novel neuronal subtypes, lack perineuronal nets. We find that cartilage link protein-1 and brevican-containing matrices form isolated perisynaptic coats, engulfing both inhibitory and excitatory terminals in the dentate gyrus and entorhinal cortex. Ultrastructural analysis revealed that presynaptic neurons contribute components of perisynaptic coats via axonal transport. We demonstrate, by combining biochemical profiling and neuroanatomy in Alzheimer's patients and transgenic (APdE9) mice, the preserved turnover and distribution of axonal coats around functional synapses along dendrite segments containing hyperphosphorylated tau and in amyloid-β-laden hippocampal microdomains. We conclude that the presynapse-driven formation of axonal coats is a candidate mechanism to maintain synapse integrity under neurodegenerative conditions.
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Máthé D, Horváth I, Szigeti K, Donohue SR, Pike VW, Jia Z, Ledent C, Palkovits M, Freund TF, Halldin C, Gulyás B. In vivo SPECT and ex vivo autoradiographic brain imaging of the novel selective CB1 receptor antagonist radioligand [125I]SD7015 in CB1 knock-out and wildtype mouse. Brain Res Bull 2013; 91:46-51. [PMID: 23318272 DOI: 10.1016/j.brainresbull.2013.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/03/2013] [Accepted: 01/04/2013] [Indexed: 02/01/2023]
Abstract
We aimed to evaluate the novel high-affinity and relatively lipophilic CB(1) receptor (CB(1)R) antagonist radioligand [(125)I]SD7015 for SPECT imaging of CB(1)Rs in vivo using the multiplexed multipinhole dedicated small animal SPECT/CT system, NanoSPECT/CT(PLUS) (Mediso, Budapest, Hungary), in knock-out CB(1) receptor knock-out (CB(1)R-/-) and wildtype mice. In order to exclude possible differences in cerebral blood flow between the two types of animals, HMPAO SPECT scans were performed, whereas in order to confirm the brain uptake differences of the radioligand between knock-out mice and wildtype mice, in vivo scans were complemented with ex vivo autoradiographic measurements using the brains of the same animals. With SPECT/CT imaging, we measured the brain uptake of radioactivity, using %SUV (% standardised uptake values) in CB(1)R-/- mice (n=3) and C57BL6 wildtype mice (n=7) under urethane anaesthesia after injecting [(125)I]SD7015 intravenously or intraperitoneally. The Brookhaven Laboratory mouse MRI atlas was fused to the SPECT/CT images by using a combination of rigid and non-rigid algorithms in the Mediso Fusion™ (Mediso, Budapest, Hungary) and VivoQuant (inviCRO, Boston, MA, USA) softwares. Phosphor imager plate autoradiography (ARG) was performed on 4 μm-thin cryostat sections of the excised brains. %SUV was 8.6±3.6 (average±SD) in CB(1)R-/- mice and 22.1±12.4 in wildtype mice between 2 and 4 h after injection (p<0.05). ARG of identically taken sections from wildtype mouse brain showed moderate radioactivity uptake when compared with the in vivo images, with a clear difference between grey matter and white matter, whereas ARG in CB(1)R(-/-) mice showed practically no radioactivity uptake. [(125)I]SD7015 enters the mouse brain in sufficient amount to enable SPECT imaging. Brain radioactivity distribution largely coincides with that of the known CB(1)R expression pattern in rodent brain. We conclude that [(125)I]SD7015 should be a useful SPECT radioligand for studying brain CB(1)R in mouse and rat disease models.
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Affiliation(s)
- Domokos Máthé
- Department of Biophysics and Radiation Biology, Semmelweis University, H-1094 Budapest, Hungary
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Shimizu T, Tanaka K, Yokotani K. Stimulatory and Inhibitory Roles of Brain 2-Arachidonoylglycerol in Bombesin-Induced Central Activation of Adrenomedullary Outflow in Rats. J Pharmacol Sci 2013; 121:157-71. [DOI: 10.1254/jphs.12208fp] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Kallendrusch S, Hobusch C, Ehrlich A, Nowicki M, Ziebell S, Bechmann I, Geisslinger G, Koch M, Dehghani F. Intrinsic up-regulation of 2-AG favors an area specific neuronal survival in different in vitro models of neuronal damage. PLoS One 2012; 7:e51208. [PMID: 23284665 PMCID: PMC3527460 DOI: 10.1371/journal.pone.0051208] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 10/30/2012] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The endocannabinoid 2-arachidonoyl glycerol (2-AG) acts as a retrograde messenger and modulates synaptic signaling e. g. in the hippocampus. 2-AG also exerts neuroprotective effects under pathological situations. To better understand the mechanism beyond physiological signaling we used Organotypic Entorhino-Hippocampal Slice Cultures (OHSC) and investigated the temporal regulation of 2-AG in different cell subsets during excitotoxic lesion and dendritic lesion of long range projections in the enthorhinal cortex (EC), dentate gyrus (DG) and the cornu ammonis region 1 (CA1). RESULTS 2-AG levels were elevated 24 h after excitotoxic lesion in CA1 and DG (but not EC) and 24 h after perforant pathway transection (PPT) in the DG only. After PPT diacylglycerol lipase alpha (DAGL) protein, the synthesizing enzyme of 2-AG was decreased when Dagl mRNA expression and 2-AG levels were enhanced. In contrast to DAGL, the 2-AG hydrolyzing enzyme monoacylglycerol lipase (MAGL) showed no alterations in total protein and mRNA expression after PPT in OHSC. MAGL immunoreaction underwent a redistribution after PPT and excitotoxic lesion since MAGL IR disappeared in astrocytes of lesioned OHSC. DAGL and MAGL immunoreactions were not detectable in microglia at all investigated time points. Thus, induction of the neuroprotective endocannabinoid 2-AG might be generally accomplished by down-regulation of MAGL in astrocytes after neuronal lesions. CONCLUSION Increase in 2-AG levels during secondary neuronal damage reflects a general neuroprotective mechanism since it occurred independently in both different lesion models. This intrinsic up-regulation of 2-AG is synergistically controlled by DAGL and MAGL in neurons and astrocytes and thus represents a protective system for neurons that is involved in dendritic reorganisation.
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Affiliation(s)
- Sonja Kallendrusch
- Institut für Anatomie, Universität Leipzig, Leipzig, Germany
- Lipid Signaling Forschungszentrum Frankfurt, Frankfurt, Germany
| | | | - Angela Ehrlich
- Institut für Anatomie, Universität Leipzig, Leipzig, Germany
| | - Marcin Nowicki
- Institut für Anatomie, Universität Leipzig, Leipzig, Germany
| | - Simone Ziebell
- Institut für Pharmakologie, Goethe Universität Frankfurt,Frankfurt, Germany
| | - Ingo Bechmann
- Institut für Anatomie, Universität Leipzig, Leipzig, Germany
| | - Gerd Geisslinger
- Institut für Pharmakologie, Goethe Universität Frankfurt,Frankfurt, Germany
| | - Marco Koch
- Institut für Anatomie, Universität Leipzig, Leipzig, Germany
| | - Faramarz Dehghani
- Institut für Anatomie, Universität Leipzig, Leipzig, Germany
- Institut für Anatomie und Zellbiologie, Martin Luther Universität, Halle-Wittenberg, Halle, Germany
- * E-mail:
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Garcia-Ovejero D, Arevalo-Martin A, Paniagua-Torija B, Sierra-Palomares Y, Molina-Holgado E. A cell population that strongly expresses the CB1 cannabinoid receptor in the ependyma of the rat spinal cord. J Comp Neurol 2012; 521:233-51. [DOI: 10.1002/cne.23184] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 06/22/2012] [Accepted: 07/06/2012] [Indexed: 01/23/2023]
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Chen R, Zhang J, Wu Y, Wang D, Feng G, Tang YP, Teng Z, Chen C. Monoacylglycerol lipase is a therapeutic target for Alzheimer's disease. Cell Rep 2012; 2:1329-39. [PMID: 23122958 DOI: 10.1016/j.celrep.2012.09.030] [Citation(s) in RCA: 190] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Revised: 06/27/2012] [Accepted: 09/26/2012] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia among older people. There are no effective medications currently available to prevent and treat AD and halt disease progression. Monoacylglycerol lipase (MAGL) is the primary enzyme metabolizing the endocannabinoid 2-arachidonoylglycerol in the brain. We show here that inactivation of MAGL robustly suppressed production and accumulation of β-amyloid (Aβ) associated with reduced expression of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) in a mouse model of AD. MAGL inhibition also prevented neuroinflammation, decreased neurodegeneration, maintained integrity of hippocampal synaptic structure and function, and improved long-term synaptic plasticity, spatial learning, and memory in AD animals. Although the molecular mechanisms underlying the beneficial effects produced by MAGL inhibition remain to be determined, our results suggest that MAGL, which regulates endocannabinoid and prostaglandin signaling, contributes to pathogenesis and neuropathology of AD, and thus is a promising therapeutic target for the prevention and treatment of AD.
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Affiliation(s)
- Rongqing Chen
- Neuroscience Center of Excellence, Louisiana State University Health New Orleans Sciences Center, New Orleans, LA 70112, USA
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Ménard C, Quirion R. Group 1 metabotropic glutamate receptor function and its regulation of learning and memory in the aging brain. Front Pharmacol 2012; 3:182. [PMID: 23091460 PMCID: PMC3469824 DOI: 10.3389/fphar.2012.00182] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 09/23/2012] [Indexed: 12/22/2022] Open
Abstract
Normal aging is generally characterized by a slow decline of cognitive abilities albeit with marked individual differences. Several animal models have been studied to explore the molecular and cellular mechanisms underlying this phenomenon. The excitatory neurotransmitter glutamate and its receptors have been closely linked to spatial learning and hippocampus-dependent memory processes. For decades, ionotropic glutamate receptors have been known to play a critical role in synaptic plasticity, a form of adaptation regulating memory formation. Over the past 10 years, several groups have shown the importance of group 1 metabotropic glutamate receptor (mGluR) in successful cognitive aging. These G-protein-coupled receptors are enriched in the hippocampal formation and interact physically with other proteins in the membrane including glutamate ionotropic receptors. Synaptic plasticity is crucial to maintain cognitive abilities and long-term depression (LTD) induced by group 1 mGluR activation, which has been linked to memory in the aging brain. The translation and synthesis of proteins by mGluR-LTD modulate ionotropic receptor trafficking and expression of immediate early genes related to cognition. Fragile X syndrome, a genetic form of autism characterized by memory deficits, has been associated to mGluR receptor malfunction and aberrant activation of its downstream signaling pathways. Dysfunction of mGluR could also be involved in neurodegenerative disorders like Alzheimer’s disease (AD). Indeed, beta-amyloid, the main component of insoluble senile plaques and one of the hallmarks of AD, occludes mGluR-dependent LTD leading to diminished functional synapses. This review highlights recent findings regarding mGluR signaling, related synaptic plasticity, and their potential involvement in normal aging and neurological disorders.
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Affiliation(s)
- Caroline Ménard
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University Montreal, QC, Canada
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Tanveer R, McGuinness N, Daniel S, Gowran A, Campbell VA. Cannabinoid receptors and neurodegenerative diseases. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/wmts.64] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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D'Addario C, Di Francesco A, Arosio B, Gussago C, Dell'Osso B, Bari M, Galimberti D, Scarpini E, Altamura AC, Mari D, Maccarrone M. Epigenetic regulation of fatty acid amide hydrolase in Alzheimer disease. PLoS One 2012; 7:e39186. [PMID: 22720070 PMCID: PMC3373611 DOI: 10.1371/journal.pone.0039186] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 05/21/2012] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVE Alzheimer disease (AD) is a progressive, degenerative and irreversible neurological disorder with few therapies available. In search for new potential targets, increasing evidence suggests a role for the endocannabinoid system (ECS) in the regulation of neurodegenerative processes. METHODS We have studied the gene expression status and the epigenetic regulation of ECS components in peripheral blood mononuclear cells (PBMCs) of subjects with late-onset AD (LOAD) and age-matched controls (CT). RESULTS We found an increase in fatty acid amide hydrolase (faah) gene expression in LOAD subjects (2.30 ± 0.48) when compared to CT (1.00 ± 0.14; *p<0.05) and no changes in the mRNA levels of any other gene of ECS elements. Consistently, we also observed in LOAD subjects an increase in FAAH protein levels (CT: 0.75 ± 0.04; LOAD: 1.11 ± 0.15; *p<0.05) and activity (pmol/min per mg protein CT: 103.80 ± 8.73; LOAD: 125.10 ± 4.00; *p<0.05), as well as a reduction in DNA methylation at faah gene promoter (CT: 55.90 ± 4.60%; LOAD: 41.20 ± 4.90%; *p<0.05). CONCLUSIONS Present findings suggest the involvement of FAAH in the pathogenesis of AD, highlighting the importance of epigenetic mechanisms in enzyme regulation; they also point to FAAH as a new potential biomarker for AD in easily accessible peripheral cells.
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Affiliation(s)
- Claudio D'Addario
- Department of Biomedical Sciences, University of Teramo, Teramo, Italy
| | | | - Beatrice Arosio
- Geriatric Unit, Department of Medical Sciences and Community Health, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Cristina Gussago
- Geriatric Unit, Department of Medical Sciences and Community Health, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Bernardo Dell'Osso
- Department of Psychiatry, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Bari
- Department of Experimental Medicine and Biochemical Sciences, Tor Vergata University, Rome, Italy
- European Center for Brain Research (CERC)/IRCCS Santa Lucia Foundation, Rome, Italy
| | - Daniela Galimberti
- Department of Neurological Sciences, “Dino Ferrari” Center, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Elio Scarpini
- Department of Neurological Sciences, “Dino Ferrari” Center, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - A. Carlo Altamura
- Department of Psychiatry, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Daniela Mari
- Geriatric Unit, Department of Medical Sciences and Community Health, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Mauro Maccarrone
- Department of Biomedical Sciences, University of Teramo, Teramo, Italy
- European Center for Brain Research (CERC)/IRCCS Santa Lucia Foundation, Rome, Italy
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Kovacs FE, Knop T, Urbanski MJ, Freiman I, Freiman TM, Feuerstein TJ, Zentner J, Szabo B. Exogenous and endogenous cannabinoids suppress inhibitory neurotransmission in the human neocortex. Neuropsychopharmacology 2012; 37:1104-14. [PMID: 22048459 PMCID: PMC3306870 DOI: 10.1038/npp.2011.262] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Activation of CB(1) receptors on axon terminals by exogenous cannabinoids (eg, Δ(9)-tetrahydrocannabinol) and by endogenous cannabinoids (endocannabinoids) released by postsynaptic neurons leads to presynaptic inhibition of neurotransmission. The aim of this study was to characterize the effect of cannabinoids on GABAergic synaptic transmission in the human neocortex. Brain slices were prepared from neocortical tissues surgically removed to eliminate epileptogenic foci. Spontaneous GABAergic inhibitory postsynaptic currents (sIPSCs) were recorded in putative pyramidal neurons using patch-clamp techniques. To enhance the activity of cannabinoid-sensitive presynaptic axons, muscarinic receptors were continuously stimulated by carbachol. The synthetic cannabinoid receptor agonist WIN55212-2 decreased the cumulative amplitude of sIPSCs. The CB(1) antagonist rimonabant prevented this effect, verifying the involvement of CB(1) receptors. WIN55212-2 decreased the frequency of miniature IPSCs (mIPSCs) recorded in the presence of tetrodotoxin, but did not change their amplitude, indicating that the neurotransmission was inhibited presynaptically. Depolarization of postsynaptic pyramidal neurons induced a suppression of sIPSCs. As rimonabant prevented this suppression, it is very likely that it was due to endocannabinods acting on CB(1) receptors. This is the first demonstration that an exogenous cannabinoid inhibits synaptic transmission in the human neocortex and that endocannabinoids released by postsynaptic neurons suppress synaptic transmission in the human brain. Interferences of cannabinoid agonists and antagonists with synaptic transmission in the cortex may explain the cognitive and memory deficits elicited by these drugs.
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Affiliation(s)
- Flora E Kovacs
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg i. Br., Germany
| | - Tim Knop
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg i. Br., Germany
| | - Michal J Urbanski
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg i. Br., Germany
| | - Ilka Freiman
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg i. Br., Germany
| | - Thomas M Freiman
- Neurochirurgische Klinik, Albert-Ludwigs-Universität, Freiburg i. Br., Germany
| | - Thomas J Feuerstein
- Neurochirurgische Klinik, Albert-Ludwigs-Universität, Freiburg i. Br., Germany
| | - Josef Zentner
- Neurochirurgische Klinik, Albert-Ludwigs-Universität, Freiburg i. Br., Germany
| | - Bela Szabo
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg i. Br., Germany,Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 25, D-79104 Freiburg i. Br., Germany, Tel: +49 761 203 5312, Fax: +49 761 203 5318, E-mail:
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Karl T, Cheng D, Garner B, Arnold JC. The therapeutic potential of the endocannabinoid system for Alzheimer's disease. Expert Opin Ther Targets 2012; 16:407-20. [PMID: 22448595 DOI: 10.1517/14728222.2012.671812] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Dementia currently affects over 35 million people worldwide. The most common form of dementia is Alzheimer's disease (AD). Currently, treatments for AD do not stop or reverse the progression of the disease and they are accompanied by side effects. AREAS COVERED The main features of AD pathology, treatment options currently available, the endocannabinoid system and its functionality in general and its role in AD pathology in detail will be outlined. A particular focus will be on the therapeutic potential of the phytocannabinoid cannabidiol. EXPERT OPINION Based on the complex pathology of AD, a preventative, multimodal drug approach targeting a combination of pathological AD symptoms appears ideal. Importantly, cannabinoids show anti-inflammatory, neuroprotective and antioxidant properties and have immunosuppressive effects. Thus, the cannabinoid system should be a prime target for AD therapy. The cannabinoid receptor 2 appears to be a promising candidate but its role in AD has to be investigated cautiously. Furthermore, the phytocannabinoid cannabidiol is of particular interest as it lacks the psychoactive and cognition-impairing properties of other cannabinoids. In conclusion, future research should focus on the evaluation of the effects of manipulations to the endocannabinoid system in established animal models for AD, combined with early-phase studies in humans.
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Affiliation(s)
- Tim Karl
- Neuroscience Research Australia, Randwick, NSW, Australia.
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Farkas S, Nagy K, Jia Z, Harkany T, Palkovits M, Donohou SR, Pike VW, Halldin C, Máthé D, Csiba L, Gulyás B. The decrease of dopamine D₂/D₃ receptor densities in the putamen and nucleus caudatus goes parallel with maintained levels of CB₁ cannabinoid receptors in Parkinson's disease: a preliminary autoradiographic study with the selective dopamine D₂/D₃ antagonist [³H]raclopride and the novel CB₁ inverse agonist [¹²⁵I]SD7015. Brain Res Bull 2012; 87:504-10. [PMID: 22421165 DOI: 10.1016/j.brainresbull.2012.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 01/24/2023]
Abstract
Cannabinoid type-1 receptors (CB₁Rs) modulate synaptic neurotransmission by participating in retrograde signaling in the adult brain. Increasing evidence suggests that cannabinoids through CB₁Rs play an important role in the regulation of motor activities in the striatum. In the present study, we used human brain samples to examine the relationship between CB₁R and dopamine receptor density in case of Parkinson's disease (PD). Post mortem putamen, nucleus caudatus and medial frontal gyrus samples obtained from PD patients were used for CB₁R and dopamine D₂/D₃ receptor autoradiography. [¹²⁵I]SD7015, a novel selective CB₁R inverse agonist, developed by a number of the present co-authors, and [³H]raclopride, a dopamine D₂/D₃ antagonist, were used as radioligands. Our results demonstrate unchanged CB₁R density in the putamen and nucleus caudatus of deceased PD patients, treated with levodopa (L-DOPA). At the same time dopamine D₂/D₃ receptors displayed significantly decreased density levels in case of PD putamen (control: 47.97 ± 10.00 fmol/g, PD: 3.73 ± 0.07 fmol/g (mean ± SEM), p<0.05) and nucleus caudatus (control: 30.26 ± 2.48 fmol/g, PD: 12.84 ± 5.49 fmol/g, p<0.0005) samples. In contrast to the putamen and the nucleus caudatus, in the medial frontal gyrus neither receptor densities were affected. Our data suggest the presence of an unaltered CB₁R population even in late stages of levodopa treated PD. This further supports the presence of an intact CB₁R population which, in line with the conclusion of earlier publications, may be utilized as a pharmacological target in the treatment of PD. Furthermore we found discrepancy between a maintained CB₁R population and a decreased dopamine D₂/D₃ receptor population in PD striatum. The precise explanation of this conundrum requires further studies with simultaneous examination of the central cannabinoid and dopaminergic systems in PD using higher sample size.
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Affiliation(s)
- Szabolcs Farkas
- Department of Neurology, University of Debrecen, H-4012 Debrecen, Hungary
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Antonucci F, Alpár A, Kacza J, Caleo M, Verderio C, Giani A, Martens H, Chaudhry FA, Allegra M, Grosche J, Michalski D, Erck C, Hoffmann A, Harkany T, Matteoli M, Härtig W. Cracking down on inhibition: selective removal of GABAergic interneurons from hippocampal networks. J Neurosci 2012; 32:1989-2001. [PMID: 22323713 PMCID: PMC3742881 DOI: 10.1523/jneurosci.2720-11.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 12/07/2011] [Accepted: 12/14/2011] [Indexed: 12/12/2022] Open
Abstract
Inhibitory (GABAergic) interneurons entrain assemblies of excitatory principal neurons to orchestrate information processing in the hippocampus. Disrupting the dynamic recruitment as well as the temporally precise activity of interneurons in hippocampal circuitries can manifest in epileptiform seizures, and impact specific behavioral traits. Despite the importance of GABAergic interneurons during information encoding in the brain, experimental tools to selectively manipulate GABAergic neurotransmission are limited. Here, we report the selective elimination of GABAergic interneurons by a ribosome inactivation approach through delivery of saporin-conjugated anti-vesicular GABA transporter antibodies (SAVAs) in vitro as well as in the mouse and rat hippocampus in vivo. We demonstrate the selective loss of GABAergic--but not glutamatergic--synapses, reduced GABA release, and a shift in excitation/inhibition balance in mixed cultures of hippocampal neurons exposed to SAVAs. We also show the focal and indiscriminate loss of calbindin(+), calretinin(+), parvalbumin/system A transporter 1(+), somatostatin(+), vesicular glutamate transporter 3 (VGLUT3)/cholecystokinin/CB(1) cannabinoid receptor(+) and neuropeptide Y(+) local-circuit interneurons upon SAVA microlesions to the CA1 subfield of the rodent hippocampus, with interneuron debris phagocytosed by infiltrating microglia. SAVA microlesions did not affect VGLUT1(+) excitatory afferents. Yet SAVA-induced rearrangement of the hippocampal circuitry triggered network hyperexcitability associated with the progressive loss of CA1 pyramidal cells and the dispersion of dentate granule cells. Overall, our data identify SAVAs as an effective tool to eliminate GABAergic neurons from neuronal circuits underpinning high-order behaviors and cognition, and whose manipulation can recapitulate pathogenic cascades of epilepsy and other neuropsychiatric illnesses.
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Affiliation(s)
- Flavia Antonucci
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
- Fondazione Filarete, I-20129 Milan, Italy
| | - Alán Alpár
- Division of Molecular Neurobiology, Department of Medical Biochemistry & Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Johannes Kacza
- Institute of Veterinary Anatomy, University of Leipzig, D-04103 Leipzig, Germany
| | - Matteo Caleo
- CNR Institute of Neuroscience, I-51600 Pisa, Italy
| | - Claudia Verderio
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
| | - Alice Giani
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
| | | | - Farrukh A. Chaudhry
- The Biotechnology Centre of Oslo & Centre for Molecular Biology and Neuroscience, University of Oslo, N-0317 Oslo, Norway
| | | | - Jens Grosche
- Paul Flechsig Institute for Brain Research, University of Leipzig, D-04109 Leipzig, Germany
| | - Dominik Michalski
- Department of Neurology, University of Leipzig, D-04103 Leipzig, Germany
| | | | - Anke Hoffmann
- Institute of Veterinary Anatomy, University of Leipzig, D-04103 Leipzig, Germany
| | - Tibor Harkany
- Division of Molecular Neurobiology, Department of Medical Biochemistry & Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
- European Neuroscience Institute, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom, and
| | - Michela Matteoli
- Department of Medical Pharmacology, CNR Institute of Neuroscience, Università di Milano and
- Instituto Clinico Humanitas, IRCCS, Rozzano, I-20089 Milan, Italy
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, D-04109 Leipzig, Germany
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Psychoyos D, Vinod KY, Cao J, Xie S, Hyson RL, Wlodarczyk B, He W, Cooper TB, Hungund BL, Finnell RH. Cannabinoid receptor 1 signaling in embryo neurodevelopment. ACTA ACUST UNITED AC 2012; 95:137-50. [PMID: 22311661 DOI: 10.1002/bdrb.20348] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 10/18/2011] [Indexed: 12/21/2022]
Abstract
In utero exposure to tetrahydrocannabinol, the psychoactive component of marijuana, is associated with an increased risk for neurodevelopmental defects in the offspring by interfering with the functioning of the endocannabinoid (eCB) system. At the present time, it is not clearly known whether the eCB system is present before neurogenesis. Using an array of biochemical techniques, we analyzed the levels of CB1 receptors, eCBs (AEA and 2-AG), and the enzymes (NAPE-PLD, DAGLα, DAGLβ, MAGL, and FAAH) involved in the metabolism of the eCBs in chick and mouse models during development. The findings demonstrate the presence of eCB system in early embryo before neurogenesis. The eCB system might play a critical role in early embryogenesis and there might be adverse developmental consequences of in utero exposure to marijuana and other drugs of abuse during this period.
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Affiliation(s)
- Delphine Psychoyos
- Center for Environmental and Genetic Medicine, Texas A&M Health Science Center, Houston, Texas 77030, USA.
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130
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Martín-Moreno AM, Brera B, Spuch C, Carro E, García-García L, Delgado M, Pozo MA, Innamorato NG, Cuadrado A, de Ceballos ML. Prolonged oral cannabinoid administration prevents neuroinflammation, lowers β-amyloid levels and improves cognitive performance in Tg APP 2576 mice. J Neuroinflammation 2012; 9:8. [PMID: 22248049 PMCID: PMC3292807 DOI: 10.1186/1742-2094-9-8] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 01/16/2012] [Indexed: 12/26/2022] Open
Abstract
Background Alzheimer's disease (AD) brain shows an ongoing inflammatory condition and non-steroidal anti-inflammatories diminish the risk of suffering the neurologic disease. Cannabinoids are neuroprotective and anti-inflammatory agents with therapeutic potential. Methods We have studied the effects of prolonged oral administration of transgenic amyloid precursor protein (APP) mice with two pharmacologically different cannabinoids (WIN 55,212-2 and JWH-133, 0.2 mg/kg/day in the drinking water during 4 months) on inflammatory and cognitive parameters, and on 18F-fluoro-deoxyglucose (18FDG) uptake by positron emission tomography (PET). Results Novel object recognition was significantly reduced in 11 month old Tg APP mice and 4 month administration of JWH was able to normalize this cognitive deficit, although WIN was ineffective. Wild type mice cognitive performance was unaltered by cannabinoid administration. Tg APP mice showed decreased 18FDG uptake in hippocampus and cortical regions, which was counteracted by oral JWH treatment. Hippocampal GFAP immunoreactivity and cortical protein expression was unaffected by genotype or treatment. In contrast, the density of Iba1 positive microglia was increased in Tg APP mice, and normalized following JWH chronic treatment. Both cannabinoids were effective at reducing the enhancement of COX-2 protein levels and TNF-α mRNA expression found in the AD model. Increased cortical β-amyloid (Aβ) levels were significantly reduced in the mouse model by both cannabinoids. Noteworthy both cannabinoids enhanced Aβ transport across choroid plexus cells in vitro. Conclusions In summary we have shown that chronically administered cannabinoid showed marked beneficial effects concomitant with inflammation reduction and increased Aβ clearance.
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Affiliation(s)
- Ana María Martín-Moreno
- Neurodenegeration Group, Dept. of Cellular, Molecular and Developmental Neurobiology, Instituto Cajal, CSIC, Doctor Arce 37, Madrid 28002, Spain
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131
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Graeber MB, Christie MJ. Multiple mechanisms of microglia: a gatekeeper's contribution to pain states. Exp Neurol 2012; 234:255-61. [PMID: 22273537 DOI: 10.1016/j.expneurol.2012.01.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 12/20/2011] [Accepted: 01/05/2012] [Indexed: 12/30/2022]
Abstract
Microglia are gatekeepers in the CNS for a wide range of pathological stimuli and they blow the whistle when things go wrong. Collectively, microglia form a CNS tissue alarm system (Kreutzberg's "sensor of pathology"), and their involvement in physiological pain is in line with this function. However, pathological neuropathic pain is characterized by microglial activation that is unwanted and considered to contribute to or even cause tactile allodynia, hyperalgesia and spontaneous pain. Such abnormal microglial behavior seems likely due to an as yet ill-understood disturbance of microglial functions unrelated to inflammation. The idea that microglia have roles in the CNS that differ from those of peripheral macrophages has gained momentum with the discovery of their separate, pre-hematopoietic lineage during embryonic development and their direct interactions with synapses.
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Affiliation(s)
- Manuel B Graeber
- Brain Tumor Research Laboratories, The Brain and Mind Research Institute, University of Sydney, Sydney, Australia.
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132
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Farkas S, Nagy K, Palkovits M, Kovács GG, Jia Z, Donohue S, Pike V, Halldin C, Máthé D, Harkany T, Gulyás B, Csiba L. [¹²⁵I]SD-7015 reveals fine modalities of CB₁ cannabinoid receptor density in the prefrontal cortex during progression of Alzheimer's disease. Neurochem Int 2011; 60:286-91. [PMID: 22222721 DOI: 10.1016/j.neuint.2011.11.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 10/25/2011] [Accepted: 11/08/2011] [Indexed: 02/01/2023]
Abstract
The cannabinoid type-1 receptor (CB₁R) is one of the most abundant members of the G protein-coupled receptor family in the central nervous system. Once activated by their cognate ligands, endocannabinoids, CB₁Rs generally limit the timing of neurotransmitter release at many cortical synapses. Prior studies have indicated the involvement of CB₁R in neurodegeneration and in various neuronal insults, with an emphasis on their neuroprotective role. In the present study we used a novel selective CB₁R radioligand to investigate regional variations in CB₁R ligand binding as a factor of progressive Braak tau pathology in the frontal cortex of Alzheimer's disease (AD) patients. The frontal cortex was chosen for this study due to the high density of CB₁Rs and their well-characterized involvement in the progression of AD. Post-mortem prefrontal cortex samples from AD patients from Braak stages I to VI and controls were subjected to CB₁R autoradiography with [¹²⁵I]SD-7015 as radioligand. Regional concentration of [¹²⁵I]SD-7015, corresponding to, and thereby representing, regional CB₁R densities, were expressed in fM/g_tissue. The results show that CB₁R density inversely correlates with Braak tau pathology with the following tendency: controls <AD Braak stage V-VI <AD Braak stage III-IV <AD Braak stage I-II. Differences were significant between control and AD Braak stage I-II groups, as well as between controls and the AD group comprising all Braak stages. These findings indicate an up-regulation of the tissue binding of the selective CB₁R radioligand [¹²⁵I]SD7015 in human brains, allowing the detection of fine modalities of receptor expression and radioligand binding during the progression of AD.
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Affiliation(s)
- Szabolcs Farkas
- Department of Neurology, University of Debrecen, H-4012 Debrecen, Hungary
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133
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Sumislawski JJ, Ramikie TS, Patel S. Reversible gating of endocannabinoid plasticity in the amygdala by chronic stress: a potential role for monoacylglycerol lipase inhibition in the prevention of stress-induced behavioral adaptation. Neuropsychopharmacology 2011; 36:2750-61. [PMID: 21849983 PMCID: PMC3230498 DOI: 10.1038/npp.2011.166] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Chronic stress is the primary environmental risk factor for the development and exacerbation of affective disorders, thus understanding the neuroadaptations that occur in response to stress is a critical step in the development of novel therapeutics for depressive and anxiety disorders. Brain endocannabinoid (eCB) signaling is known to modulate emotional behavior and stress responses, and levels of the eCB 2-arachidonoylglycerol (2-AG) are elevated in response to chronic homotypic stress exposure. However, the role of 2-AG in the synaptic and behavioral adaptations to chronic stress is poorly understood. Here, we show that stress-induced development of anxiety-like behavior is paralleled by a transient appearance of low-frequency stimulation-induced, 2-AG-mediated long-term depression at GABAergic synapses in the basolateral amygdala, a key region involved in motivation, affective regulation, and emotional learning. This enhancement of 2-AG signaling is mediated, in part, via downregulation of the primary 2-AG-degrading enzyme monoacylglycerol lipase (MAGL). Acute in vivo inhibition of MAGL had little effect on anxiety-related behaviors. However, chronic stress-induced anxiety-like behavior and emergence of long-term depression of GABAergic transmission was prevented by chronic MAGL inhibition, likely via an occlusive mechanism. These data indicate that chronic stress reversibly gates eCB synaptic plasticity at inhibitory synapses in the amygdala, and in vivo augmentation of 2-AG levels prevents both behavioral and synaptic adaptations to chronic stress.
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Affiliation(s)
- Joshua J Sumislawski
- Department of Psychiatry, Vanderbilt University Medical Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Teniel S Ramikie
- Neuroscience Graduate Program, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Sachin Patel
- Department of Psychiatry, Vanderbilt University Medical Center, Vanderbilt University School of Medicine, Nashville, TN, USA,Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Vanderbilt University School of Medicine, Nashville, TN, USA,Department of Psychiatry, and Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Vanderbilt University School of Medicine, Robinson Research Building, Room 724B, Nashville, TN 37212, USA, Tel: +1 615 936 7768, Fax: +1 615 322 1462, E-mail:
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Duarte JMN, Ferreira SG, Carvalho RA, Cunha RA, Köfalvi A. CB₁ receptor activation inhibits neuronal and astrocytic intermediary metabolism in the rat hippocampus. Neurochem Int 2011; 60:1-8. [PMID: 22085448 DOI: 10.1016/j.neuint.2011.10.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 10/21/2011] [Accepted: 10/31/2011] [Indexed: 01/30/2023]
Abstract
Cannabinoid CB₁ receptor (CB₁R) activation decreases synaptic GABAergic and glutamatergic transmission and it also controls peripheral metabolism. Here we aimed at testing with ¹³C NMR isotopomer analysis whether CB₁Rs could have a local metabolic role in brain areas having high CB₁R density, such as the hippocampus. We labelled hippocampal slices with the tracers [2-¹³C]acetate, which is oxidized in glial cells, and [U-¹³C]glucose, which is metabolized both in glia and neurons, to evaluate metabolic compartmentation between glia and neurons. The synthetic CB₁R agonist WIN55212-2 (1 μM) significantly decreased the metabolism of both [2-¹³C]acetate (-11.6±2.0%) and [U-¹³C]glucose (-11.2±3.4%) in the tricarboxylic acid cycle that contributes to the glutamate pool. WIN55212-2 also significantly decreased the metabolism of [U-¹³C]glucose (-11.7±4.0%) but not that of [2-¹³C]acetate contributing to the pool of GABA. These effects of WIN55212-2 were prevented by the CB₁R antagonist AM251 (500 nM). These results thus suggest that CB₁Rs might be present also in hippocampal astrocytes besides their well-known neuronal localization. Indeed, confocal microscopy analysis revealed the presence of specific CB₁R immunoreactivity in astrocytes and pericytes throughout the hippocampus. In conclusion, CB₁Rs are able to control hippocampal intermediary metabolism in both neuronal and glial compartments, which suggests new alternative mechanisms by which CB₁Rs control cell physiology and afford neuroprotection.
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Affiliation(s)
- João M N Duarte
- Center for Neurosciences and Cell Biology of Coimbra, University of Coimbra, Coimbra, Portugal
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