title: Methods to study the behavioral effects and expression of CB2 cannabinoid receptor and its gene transcripts in the chronic mild stress model of depression.
abstract: Behavioral and molecular methods were used to study and determine whether there is a link between depression that may be a factor in drug/alcohol addiction, and the endocannabinoid hypothesis of substance abuse. Depression is a lack of interest in the pleasurable things of life (termed anhedonia) and depressed mood. It is unknown whether CB2 cannabinoid receptors are expressed in the brain and whether they are involved in depression and substance abuse. Therefore, mice were subjected daily for 4 wk to chronic mild stress (CMS), and anhedonia was measured by the consumption of 2% sucrose solution. Behavioral and rewarding effects of abused substances were determined in the CMS and control animals. The expression of CB2 receptors and their gene transcripts was compared in the brains of CMS and control animals by Western blotting using CB2 receptor antibody and reverse transcriptase-polymerase chain reaction (RT-PCR). Furthermore, the expression and immunocytochemical identification of CB2 cannabinoid receptor in the rat brain were determined. CMS induced gender-specific aversions, which were blocked by WIN55,212-2, a nonspecific CB1 and CB2 cannabinoid receptor agonist. Direct CB2 antisense oligonucleotide microinjection into the mouse brain induced anxiolysis, indicating that CB2 or CB2-like receptors are present in the brain and may influence behavior. The major finding from these studies was the expression of CB2 receptor and its gene transcript in the mouse brain, which was enhanced by CMS. These preliminary results, if confirmed, suggest that the CB2 receptors are expressed in the mammalian brain and may be involved in depression and substance abuse.
authors.affiliation: Department of Biology, William Paterson University, Wayne, NJ, USA.
authors.forename: Emmanuel S
authors.initials: ES
authors.lastname: Onaivi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ishiguro
authors.forename: Patel
authors.initials: P
authors.lastname: Sejal
authors.forename: Paul A
authors.initials: PA
authors.lastname: Meozzi
authors.forename: Lester
authors.initials: L
authors.lastname: Myers
authors.forename: Patricia
authors.initials: P
authors.lastname: Tagliaferro
authors.forename: Bruce
authors.initials: B
authors.lastname: Hope
authors.forename: Claire M
authors.initials: CM
authors.lastname: Leonard
authors.forename: George R
authors.initials: GR
authors.lastname: Uhl
authors.forename: Alicia
authors.initials: A
authors.lastname: Brusco
authors.forename: Eileen
authors.initials: E
authors.lastname: Gardner
mesh_terms: D000818:Animals; D001483:Base Sequence; D001522:Behavior, Animal; D015153:Blotting, Western; D017931:DNA Primers; D003863:Depression / Q000235:genetics / Q000503:physiopathology*; D004195:Disease Models, Animal; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D043885:Receptor, Cannabinoid, CB2 / Q000235:genetics* / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D043885:Receptor, Cannabinoid, CB2