title: Differential effects of single versus repeated alcohol withdrawal on the expression of endocannabinoid system-related genes in the rat amygdala.
abstract: BACKGROUND
  Endogenous cannabinoids such as anandamide and 2-arachidonoylglycerol (2-AG) exert important regulatory influences on neuronal signaling, participate in short- and long-term forms of neuroplasticity, and modulate stress responses and affective behavior in part through the modulation of neurotransmission in the amygdala. Alcohol consumption alters brain endocannabinoid levels, and alcohol dependence is associated with dysregulated amygdalar function, stress responsivity, and affective control.
  
  
  METHODS
  The consequence of long-term alcohol consumption on the expression of genes related to endocannabinoid signaling was investigated using quantitative RT-PCR analyses of amygdala tissue. Two groups of ethanol (EtOH)-exposed rats were generated by maintenance on an EtOH liquid diet (10%): the first group received continuous access to EtOH for 15 days, whereas the second group was given intermittent access to the EtOH diet (5 d/wk for 3 weeks). Control subjects were maintained on an isocaloric EtOH-free liquid diet. To provide an initial profile of acute withdrawal, amygdala tissue was harvested following either 6 or 24 hours of EtOH withdrawal.
  
  
  RESULTS
  Acute EtOH withdrawal was associated with significant changes in mRNA expression for various components of the endogenous cannabinoid system in the amygdala. Specifically, reductions in mRNA expression for the primary clearance routes for anandamide and 2-AG (fatty acid amide hydrolase [FAAH] and monoacylglycerol lipase [MAGL], respectively) were evident, as were reductions in mRNA expression for CB(1) , CB(2) , and GPR55 receptors. Although similar alterations in FAAH mRNA were evident following either continuous or intermittent EtOH exposure, alterations in MAGL and cannabinoid receptor-related mRNA (e.g., CB(1) , CB(2) , GPR55) were more pronounced following intermittent exposure. In general, greater withdrawal-associated deficits in mRNA expression were evident following 24 versus 6 hours of withdrawal. No significant changes in mRNA expression for enzymes involved in 2-AG biosynthesis (e.g., diacylglicerol lipase-α/β) were found in any condition.
  
  
  CONCLUSIONS
  These findings suggest that EtOH dependence and withdrawal are associated with dysregulated endocannabinoid signaling in the amygdala. These alterations may contribute to withdrawal-related dysregulation of amygdalar neurotransmission.
authors.affiliation: Laboratorio de Medicina Regenerativa, Hospital Regional Universitario Carlos Haya, Fundacion IMABIS, 29010 Malaga, Spain.
authors.forename: Antonia
authors.initials: A
authors.lastname: Serrano
authors.forename: Patricia
authors.initials: P
authors.lastname: Rivera
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Pavon
authors.forename: Juan
authors.initials: J
authors.lastname: Decara
authors.forename: Juan
authors.initials: J
authors.lastname: Suárez
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodriguez de Fonseca
authors.forename: Loren H
authors.initials: LH
authors.lastname: Parsons
mesh_terms: D000581:Amidohydrolases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism*; D002492:Central Nervous System Depressants / Q000009:adverse effects*; D063388:Endocannabinoids; D000431:Ethanol / Q000009:adverse effects*; D015870:Gene Expression / Q000187:drug effects*; D020869:Gene Expression Profiling; D008297:Male; D008994:Monoacylglycerol Lipases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D043882:Receptors, Cannabinoid / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013375:Substance Withdrawal Syndrome; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D063385:Cannabinoid Receptor Modulators; D002492:Central Nervous System Depressants; D063388:Endocannabinoids; D000431:Ethanol; D008994:Monoacylglycerol Lipases; D012333:RNA, Messenger; D043882:Receptors, Cannabinoid; D000099252:Fatty Acid Amide Hydrolases