For over a decade, until recently, it was thought that marijuana acts by activating brain-type cannabinoid receptors called CB1, and that a second type called CB2 cannabinoid receptor was found only in peripheral tissues. Neuronal CB2 receptors in the brain had been controversial. We reported the discovery and functional presence of CB2 cannabinoid receptors in the mammalian brain that may be involved in depression and drug abuse and this was supported by reports of identification of neuronal CB2 receptors that are involved in emesis. RT-PCR, immunoblotting, hippocampal cultures, immunohistochemistry, transmission electron microscopy, and stereotaxic techniques with behavioral assays were used to determine the functional expression of CB2 cannabinoid receptors in the rat brain and mouse brain exposed to chronic mild stress or treated with abused drugs. RT-PCR analyses supported the expression of brain CB2 receptor transcripts at levels much lower than those of CB1 receptors. In situ hybridization revealed CB2 mRNA in cerebellar neurons of wild-type but not of CB2 knockout mice. Abundant CB2 receptor immunoreactivity (iCB2) in neuronal and glial processes was detected in the brain. The effect of direct CB2 antisense oligonucleotide injection into the brain and treatment with JWH015 in motor function and plus-maze tests also demonstrated the functional presence of CB2 cannabinoid receptors in the central nervous system. In humans, there was a high incidence of Q63R polymorphism in the CB2 gene in Japanese alcoholics and depressed subjects. Contrary to the prevailing view that CB2 cannabinoid receptors are restricted to peripheral tissues and predominantly in immune cells, we demonstrated that CB2 cannabinoid receptors and their gene transcripts are widely distributed in the brain. This multifocal expression of iCB2 in the brain suggests that CB2 receptors may play broader roles than previously anticipated and may therefore be exploited as new targets in the treatment of depression and substance abuse.
© 2006 S. Karger AG, Basel
- CB2 cannabinoid receptor
- CB2 gene
- CB2 polyclonal antibody
- CB2 knockout mice
- CB2 electron micrograph from brain neurons
- Matsuda LA, Lolait TI, Bownstein MJ, Young AC, Bonner TI: Structure of a cannabinoid receptor and functional expression of the cloned cDNA. Nature 1990;346:561–564.
- Onaivi ES, Ishiguro H, Lin Z, Akinshola BE, Zhang PW, Uhl GR: Cannabinoid receptor genetics and behavior; in Onaivi ES (ed): Biology of Marijuana: From Gene to Behavior. Boca Raton, Taylor and Francis, 2002, pp 1–44.
- Munro S, Thomas KL, Abu-Shaar M: Molecular characterization of a peripheral receptor for cannabinoids. Nature 1993;365:61–65.
- Meozzi PA, Patel S, Myers L, Leonard CM, Gardner E, Onaivi ES: Decreased alcohol consumption and enhanced cannabinoid CB2 receptor expression in mouse chronic mild stress model of depression. 7th Annu Undergraduate Res Symp Chem Biol Sci, Baltimore, 2004.
- Onaivi ES, Ishiguro H, Patel S, Meozzi PA, Myers L, Tagliaferro P, Leonard CM, Gardner E, Brusco A, Akinshola BE, Liu QR, Hope B, Uhl GR: Presence and functional expression of peripheral cannabinoid CB2 receptors in the brain. Coll Probl Drug Depend Annu Meet, Orlando, 2005.
- Onaivi ES, Ishiguro H, Gong JP, Patel S, Meozzi PA, Myers L, Tagliaferro P, Leonard CM, Gardner E, Brusco A, Akinshola BE, Liu QR, Hope B, Uhl GR: Peripheral cannabinoid CB2 receptors are expressed in the brain and involved in depression and substance abuse. ICRS Symp Cannabinoids, Vermont, 2005, p 66.
- Onaivi ES, Ishiguro H, Gong JP, Patel S, Meozzi PA, Myers L, Mora Z, Perchuk P, Tagliaferro P, Leonard CM, Gardner E, Brusco A, Akinshola BE, Liu QR, Hope B, Uhl GR: Presence and functional expression of CB2 cannabinoid receptors in brain that is involved in depression and substance abuse. Int Soc Neurochem/Eur Soc Neurochem Satellite Meet, Isola di San Servolo, Venice, 2005.
- Gong JP, Onaivi ES, Uhl GR: Cannabinoid CB2 receptors: immunohistochemical localization in rat brain. ICRS Symp Cannabinoids, Vermont, 2005, p 91.
- Onaivi ES, Ishiguro H, Gong JP, Patel S, Meozzi PA, Myers L, Mora Z, Perchuk P, Tagliaferro P, Leonard CM, Gardner E, Brusco A, Akinshola BE, Liu QR, Hope B, Uhl GR: Presence and functional expression of CB2 cannabinoid receptors in the brain that is involved in depression and substance abuse. Int Narc Res Soc Meet, Annapolis, 2005.
- Gong JP, Onaivi ES, Uhl GR: Peripheral cannabinoid CB2 receptors: expression in neuronal patterns and localization in rat brain. Int Narc Res Soc Meet, Annapolis, 2005.
- Onaivi ES, Ishiguro H, Gong JP, Patel S, Meozzi PA, Myers L, Mora Z, Perchuk P, Tagliaferro P, Leonard CM, Gardner E, Brusco A, Akinshola BE, Liu QR, Hope B, Uhl GR: Discovery of the presence and functional expression of CB2 cannabinoid receptors in brain that is involved in depression and substance abuse. Soc Neurosci Abstr, Washington, 2005.
- Onaivi ES, Ishiguro H, Patel S, Meozzi PA, Myers L, Tagliaferro P, Hope B, Leonard CM, Uhl GR, Brusco A, Gardner E: Methods to study the behavioral effects and expression of CB2 cannabinoid receptors and its gene transcripts in chronic mild stress model of depression; in Onaivi ES (ed): Marijuana and Cannabinoid Research: Methods and Protocols. Totowa, Humana Press Inc, 2006, pp 291–298.
- Berdyshev EV: Cannabinoid receptors and the regulation of immune response. Chem Phys Lipids 2000;108:169–190.
- Suigiura T, Waku K: 2-Arachidonoylglycerol and cannabinoid receptors. Chem Phys Lipids 2000;108:89–106.
- Wilson RI, Nicoll R: Endogenous cannabinoids mediate retrograde signaling at hippocampal synapses. Nature 2001;410:588–592.
- Carlisle SJ, Marciano-Cabral F, Staab A, Ludwick C, Cabral GA: Differential expression of the CB2 cannabinoid receptor by rodent macrophages and macrophage-like cells in relation to cell activation. Int J Immunopharmacol 2002;2:69–82.
- Derocq JM, Segui M, Marchand J, Le Fur G, Casellas P: Cannabinoids enhance human B-cell growth at low nanomolar concentrations. FEBS Lett 1995;369:177–182.
- Galiegue S, Mary S, Marchand J, Dussossoy D, Carriere D, Carayon P, Bouaboula M, Shire D, Le Fur G, Casellas P: Expression of central and peripheral cannabinoid receptors in human immune tissues and leukocyte subpopulations. Eur J Biochem 1995;232:54–61.
- Griffin G, Wray EJ, Tao Q, McAllister SD, Rorrer WK, Aung M, Martin BR, Abood M: Evaluation of the cannabinoid CB2 receptor-selective antagonist, SR144528: further evidence for CB2 receptor absence in the rat central nervous system. Eur J Pharmacol 1999;377:117–125.
- Shatz AR, Lee M, Condie RB, Pulaski JT, Kaminski NE: Cannabinoid receptors CB1 and CB2: a characterization of expression and adenylate cyclase modulation within the immune system. Toxicol Appl Pharmacol 1997;142:278–287.
- Ibrahim M, Deng H, Zvonok K, Cockayne DA, Kwan J, Mata HP, Vandrah TW, Lai J, Porreca F, Makriyannis A, Malan TP: Activation of CB2 cannabinoid receptors by AM1241 inhibits experimental neuropathic pain: pain inhibition by receptors not present in the brain. Proc Natl Acad Sci USA 2003;100:10529–10533.
- Kearn CS, Hilliard CJ: Rat microglial cell expresses the peripheral-type cannabinoid receptor (CB2) which is negatively coupled to adenylyl cyclase. ICRS Symp Cannabinoids, Vermont, 1997, p 61.
- Skaper SD, Buriani A, Dal Toso R, Petrelli L, Romanello S, Facci L, Leon A: The ALIAmide palmitoylethanolamide and cannabinoids, but not anandamide, are protective in a delayed postglutamate paradigm of excitotoxic death in cerebral granule neurons. Proc Natl Acad Sci USA 1996;93:3984–3989.
- Facci L, Dal Toso Romanello S, Buriani A, Skaper SD, Leona A: Mast cells express a peripheral cannabinoid receptor with differential sensitivity to anandamide and palmitoylethanolamide. Proc Natl Acad Sci USA 1995;92:3376–3380.
- Samson MT, Small-Howard A, Shimoda LMN, Koblan-Huberson M, Stokes AJ, Turner H: Differential roles of CB1 and CB2 cannabinoid receptors in mast cells. J Immunol 2003;170:4953–4962.
- Lu Q, Straiker A, Lu Q, Maguire G: Expression of CB2 cannabinoid receptor mRNA in adult rat retina. Vis Neurosci 2000;17:91–95.
- Sheng WS, Hu S, Min X, Cabral GA, Lokensgard JR, Peterson PK: Synthetic cannabinoid WIN55212–2 inhibits generation of inflammatory mediators by IL-1beta-stimulated human astrocytes. Glia 2005;49:211–219.
- Benito C, Kim WK, Chavarria I, Hillard CJ, Mackie K, Tolon RM, Williams K, Romero J: A glial endogenous cannabinoid system is upregulated in the brains of macaques with simian immunodeficiency virus-induced encephalitis. J Neurosci 2005;25:2530–2536.
- Nunez E, Benito C, Pazos MR, Barbachano A, Fajardo O, Gonzalez S, Tolon RM, Romero J: Cannabinoid CB2 receptors are expressed by perivascular microglia cells in the human brain: an immunohistochemical study. Synapse 2004;53:208–213.
- Pazos MR, Nunez E, Benito C, Tolon RM, Romero J: Role of the endocannabinoid system in Alzheimer’s disease: new perspectives. Life Sci 2004;75:1907–1915.
- Golech SA, McCarron RM, Chen Y, Bembry J, Lenz F, Mechoulam R, Shohami E, Spatz M: Human brain endothelium: coexpression and function of vanilloid and endocannabinoid receptors. Brain Res Mol Brain Res 2004;132:87–92.
- Ben-Shabat S, Fride E, Sheskin T, Tsippy T, Rhee MH, Vogel Z, Bisogno T, De Petrocellis L, Di Marzo V, Mechoulam R: An entourage effect: inactive endogenous fatty acid glycerol esters enhance 2-arachidonyl-glycerol cannabinoid activity. Eur J Pharmacol1998;353:23–31.
- Benito C, Nunez E, Tolon RM, Carrier EJ, Rabano A, Hillard CJ, Romero J: Cannabinoid CB2 receptors and fatty acid amide hydrolase are selectively overexpressed in neuritic plaque-associated glia in Alzheimer’s disease brains. J Neurosci 2003;23:11136–11141.
- Chakrabarti A, Rossby SP, Manier DH, Perrin C, Onaivi ES, Sulser F: Molecular correlates of a chronic mild stress model of depression. Abstr Soc Neurosci 1996;22:2060.
- Willner P: Chronic mild stress (CMS) revisited: consistency and behavioural-neurobiological concordance in the effects of CMS. Neuropsychobiology 2005;52:90–110.
- Franklin KBJ, Paxinos G: The Mouse Brain in Stereotaxic Coordinates. San Diego, Academic Press, 1997.
- Gong JP, Onaivi ES, Ishiguro H, Liu QR, Tagliaferro P, Brusco A, Uhl GR: Cannabinoid CB2 receptors: immunohistochemical localization in rat brain. Brain Res 2006;1071:10–23.
- Pettit DA, Harrison MP, Olson JM, Spencer RF, Cabral GA: Immunohistochemical localization of the neural cannabinoid receptor in rat brain. Neurosci Res 1998;51:391–342.
- Tsou K, Brown S, Sanudo-Pena MC, Mackie K, Walker JM: Immunohistochemical distribution of cannabinoid CB1 receptors in the rat central nervous system. Neuroscience 1998;83:393–411.
- Van Sickle MD, Duncan M, Kingsley PJ, Mouihate A, Urbani P, Mackie K, Stella N, Makriyannis A, Piomelli D, Davison JS, Marnett LJ, Di Marzo V, Pittman QJ, Patel KD, Sharkey KA: Identification and functional characterization of brainstem cannabinoid CB2 receptors. Science 2005;310:329–332.
- Ashton JC, Friberg D, Darlington CL, Smith PF: Expression of the cannabinoid CB2 receptor in the rat cerebellum: an immunohistochemical study. Neurosci Lett 2005;396:113–116.
- Beltramo M, Bernardini N, Bertorelli R, Campnella M, Nicolussi E, Fredduzzi S, Reggiani A: CB2 receptor-mediated antihyperalgesia: possible direct involvement of neural mechanisms. Eur J Neurosci 2006;23:1530–1538.
- Little P, Stabley GJ, Worm K, Sauei CT, Zhou Q, Conway-James N: Detection of cataleptic effects of selective CB2 receptor agonist in rats. CPDD Abstract 2006:470.
- Zhang PW, Ishiguro H, Ohtsuki T, Carillo F, Walther D, Onaivi ES, Arinami T, Uhl GR: Human cannabinoid receptor 1: 5′ exons, candidate regulatory regions, polymorphisms, haplotypes and association with polysubstance abuse. Mol Psychiatry 2004;9:916–931.
- Sipe JC, Arbour N, Gerber A, Beutler E: Reduced endocannabinoid immune modulation by a common cannabinoid 2 (CB2) receptor gene polymorphism: possible risk for autoimmune disorders. J Leukoc Biol 2005;78:231–238.
- Brown SM, Wagner-Miller J, Mackie K: Cloning and molecular characterization of the rat CB2 cannabinoid receptor. Biochim Biophys Acta 2002;1576:255–264.
- Karsak M, Cohen-Solal M, Freudenberg J, Ostertag A, Morieux C, Kornak U, Essig J, Erxlebe E, Bab I, Kubisch C, de Vernejoul MC, Zimmer A: Cannabinoid receptor type 2 gene is associated with human osteoporosis. Hum Mol Genet 2005;14:3389–3396.
- Lauckner JE, Reyes F, Xu C, Hille B, Stella N, Mackie K: Distribution and functional characterization of a novel cannabinoid receptor. Soc Neurosci Abstr, Washington, 2005.
- Sawzdargo M, Nguyen T, Lee DK, Lynch KR, Cheng R, Heng HHQ, George SR, O’Dowd BF: Identification and cloning of three novel human G protein-coupled receptor genes GPR52, GPR53 and GPR55: GPR55 is extensively expressed in human brain. Brain Res Mol Brain Res 1999;64:193–198.
- Onaivi ES, Ishiguro H, Zhang PW, Lin Z, Akinshola BE, Leonard CM, Chirwa SS, Gong JP, Uhl GR: Endocannabinoid receptor genetics and marijuana use; in Onaivi ES, Sugiura T, Di Marzo V (eds): Endocannabinoids: The Brain and Body’s Marijuana and beyond. Boca Raton, Taylor & Francis, 2006, pp 57–118.
- Di Marzo V, Breivogel CS, Tao Q, Bridgen DT, Razdan RK, Zimmer AM, Zimmer A, Martin BR: Levels, metabolism, and pharmacological activity of anandamide in CB(1) cannabinoid receptor knockout mice: evidence for non-CB(1), non-CB(2) receptor-mediated actions of anandamide in mouse brain. J Neurochem 2000;75:2434–2444.
- Hill MN, Patel EJ, Carrier EJ, Rademacher DJ, Ormerod BK, Hillard CJ, Gorzalka BB: Downregulation of endocannabinoid signaling in the hippocampus following chronic unpredictable stress. Neuropsychopharmacology 2004;30:508–511.
- Fride E, Suris R: Differential response to acute and repeated stress in cannabinoid CB1 receptor knockout newborn and adult mice. Behav Pharmacol 2005;16:431–471.
- Hill MN, Gorzalka BB: Is there a role for the endocannabinoid system in the etiology and treatment of melancholic depression. Behav Pharmacol 2005;16:333–352.
- Valenzano KJ, Tafasse L, Lee G, Harrison JE, Boulet JM, Gottshall SL, Mark L, Pearson MS, Miller W, Shan S, Rabadi L, Rotshteyn Y, Chaffer SM, Turchin PI, Elsemore Y, Toth M, Koetzner L, Whiteside GT: Pharmacological and pharmacokinetic characterization of the cannabinoid receptor 2 agonist, GW405833, utilizing rodent models of acute and chronic pain, anxiety, ataxia and catalepsy. Neuropharmacology 2005;48:658–672.
- Kurreck J: Antisense technologies. Improvement through novel chemical modifications. Eur J Biochem 2003;270:1628–1644.
- Nieri P, Greco R, Adinolfi B, Breschi MC, Martinotti E, Nannetti C, Podesta A: CB1- and CB2-cannabinoid receptor-independent lipolysis induced by WIN 55,212–2 in male rat adipocytes. Naunyn Schmiedebergs Arch Pharmacol 2003;368:352–359.
- Ehrhart J, Obregon D, Mori T, Hou H, Sun N, Bai Y, Klein T, Fernandez F, Tan J, Shytle RD: Stimulation of cannabinoid receptor 2 (CB2) suppresses microglial activation. J Neuroinflammation 2005;2:29.
- Zhong L, Geng L, Njie Y, Feng W, Song ZH: CB2 cannabinoid receptors in trabecular meshwork cells mediate JWH015-induced enhancement of aqueous humor outflow facility. Invest Ophthalmol Vis Sci 2005;46:1988–1992.
- Pellow S, Chopin P, File SE, Briley M: Validation of open:closed arm entries in an elevated plus-maze as a measure of anxiety in the rat. J Neurosci Methods 1985;14:149–167.
- Lister RG: The use of a plus-maze to measure anxiety in the mouse. Psychopharmacology 1987;92:180–185.
- Klein TW, Newton C, Larsen K, Lu L, Perkins I, Nong L: The cannabinoid system and immune modulation. J Leukocyte Biol 2003;74:486–496.
- Lee SF, Newton C, Widen R, Friedman H, Klein TW: Differential expression of cannabinoid CB2 receptor mRNA in mouse immune cell subpopulation and following B cell stimulation. J Pharmacol 2001;423:235–241.
- Buckley NE, McCoy KL, Mezey E, Bonner T, Zimmer A, Felder CC, Glass M, Zimmer A: Immunomodulation by cannabinoids is absent in mice deficient for the cannabinoid CB2 receptor. Eur J Pharmacol 2000;396:141–149.
Emmanuel S. Onaivi, PhD
Department of Biology
William Paterson University
Wayne, NJ 07470 (USA)
Tel. +1 973 720 3453, Fax +1 973 720 2338, E-Mail Onaivie@wpunj.edu
Received: January 2, 2006
Accepted after revision: December 17, 2006
Published online: March 15, 2007
Number of Print Pages : 16
Number of Figures : 7, Number of Tables : 0, Number of References : 64
Neuropsychobiology (International Journal of Experimental and Clinical Research in Biological Psychiatry, Pharmacopsychiatry, Biological Psychology/Pharmacopsychology and Pharmacoelectroencephalography)
Vol. 54, No. 4, Year 2006 (Cover Date: April 2007)
Journal Editor: Strik, W. (Bern)
ISSN: 0302–282X (print), 1423–0224 (Online)
For additional information: http://www.karger.com/NPS
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.