PURPOSE: Recent biochemical and post-mortem evidence suggests involvement of the endocannabinoid system in alcohol drinking behaviour and dependence. Using [(18)F]MK-9470 small-animal PET imaging, our primary objective was to evaluate in vivo type 1 cannabinoid receptor (CB1R) binding changes in rats subjected to several ethanol conditions: (1) at baseline, (2) after acute intraperitoneal administration of ethanol (4 g/kg) or saline, (3) after 7 days of forced chronic ethanol consumption, and (4) after abstinence for 7 and 14 days. Secondly, levels of anandamide (AEA) in the nucleus accumbens (NAcc) were investigated in the same animals using in vivo microdialysis and correlated with the changes in CB1R binding. METHODS: In total, 28 male Wistar rats were investigated. Small-animal PET was done on a FOCUS-220 tomograph with [(18)F]MK-9470. Parametric images of [(18)F]MK-9470 binding based on standard uptake values (SUV, as a measure of CB1R binding) were generated. Images were normalized to Paxinos space and analysed voxel-wise using SPM8 (p(height) = 0.005; k(ext) = 200). The AEA content was quantified using HPLC with tandem mass spectrometry detection. RESULTS: Acute ethanol administration increased relative CB1R binding in the NAcc that was positively correlated with the change in AEA levels of that region. In contrast, compared to rats at baseline, AEA levels in the NAcc were not significantly different in rats after chronic ethanol consumption or after a 14-day abstinence period. Chronic ethanol consumption decreased relative CB1R binding in the hippocampus and caudate-putamen, whereas same regions showed increased relative CB1R binding after 7 and 14 days of abstinence compared to the baseline condition. After 7 and 14 days of abstinence, relative CB1R binding additionally decreased in the orbitofrontal cortex. The magnitude of the hippocampal and frontal changes was highly correlated with daily ethanol intake. CONCLUSION: This study provides in vivo evidence that acute ethanol consumption is associated with enhanced endocannabinoid signalling in the NAcc, indicated by an increased CB1R binding and AEA content. In addition, chronic ethanol exposure leads to regional dysfunctions in CB1R levels, involving the hippocampus and caudate-putamen that are reversible within 2 weeks in this animal model.
PURPOSE: Recent biochemical and post-mortem evidence suggests involvement of the endocannabinoid system in alcohol drinking behaviour and dependence. Using [(18)F]MK-9470 small-animal PET imaging, our primary objective was to evaluate in vivo type 1 cannabinoid receptor (CB1R) binding changes in rats subjected to several ethanol conditions: (1) at baseline, (2) after acute intraperitoneal administration of ethanol (4 g/kg) or saline, (3) after 7 days of forced chronic ethanol consumption, and (4) after abstinence for 7 and 14 days. Secondly, levels of anandamide (AEA) in the nucleus accumbens (NAcc) were investigated in the same animals using in vivo microdialysis and correlated with the changes in CB1R binding. METHODS: In total, 28 male Wistar rats were investigated. Small-animal PET was done on a FOCUS-220 tomograph with [(18)F]MK-9470. Parametric images of [(18)F]MK-9470 binding based on standard uptake values (SUV, as a measure of CB1R binding) were generated. Images were normalized to Paxinos space and analysed voxel-wise using SPM8 (p(height) = 0.005; k(ext) = 200). The AEA content was quantified using HPLC with tandem mass spectrometry detection. RESULTS: Acute ethanol administration increased relative CB1R binding in the NAcc that was positively correlated with the change in AEA levels of that region. In contrast, compared to rats at baseline, AEA levels in the NAcc were not significantly different in rats after chronic ethanol consumption or after a 14-day abstinence period. Chronic ethanol consumption decreased relative CB1R binding in the hippocampus and caudate-putamen, whereas same regions showed increased relative CB1R binding after 7 and 14 days of abstinence compared to the baseline condition. After 7 and 14 days of abstinence, relative CB1R binding additionally decreased in the orbitofrontal cortex. The magnitude of the hippocampal and frontal changes was highly correlated with daily ethanol intake. CONCLUSION: This study provides in vivo evidence that acute ethanol consumption is associated with enhanced endocannabinoid signalling in the NAcc, indicated by an increased CB1R binding and AEA content. In addition, chronic ethanol exposure leads to regional dysfunctions in CB1R levels, involving the hippocampus and caudate-putamen that are reversible within 2 weeks in this animal model.
Authors: Markus S H Henniger; Rainer Spanagel; Alexandra Wigger; Rainer Landgraf; Sabine M Hölter Journal: Neuropsychopharmacology Date: 2002-06 Impact factor: 7.853
Authors: K Yaragudri Vinod; Ratnakumar Yalamanchili; Shan Xie; Thomas B Cooper; Basalingappa L Hungund Journal: Neurochem Int Date: 2006-07-05 Impact factor: 3.921
Authors: Sara Gonzalez; Javier Fernandez-Ruiz; Valentina Sparpaglione; Daniela Parolaro; Jose A Ramos Journal: Drug Alcohol Depend Date: 2002-03-01 Impact factor: 4.492
Authors: Cindy Casteels; Peter Vermaelen; Johan Nuyts; Annemie Van Der Linden; Veerle Baekelandt; Luc Mortelmans; Guy Bormans; Koen Van Laere Journal: J Nucl Med Date: 2006-11 Impact factor: 10.057
Authors: Yan Zhou; Benjamin I Schwartz; Joanna Giza; Steven S Gross; Francis S Lee; Mary Jeanne Kreek Journal: Psychopharmacology (Berl) Date: 2017-07-20 Impact factor: 4.530
Authors: Francisco J Pavón; Antonia Serrano; David G Stouffer; Ilham Polis; Marisa Roberto; Benjamin F Cravatt; Rémi Martin-Fardon; Fernando Rodríguez de Fonseca; Loren H Parsons Journal: Addict Biol Date: 2018-11-13 Impact factor: 4.280
Authors: Florence P Varodayan; Neeraj Soni; Michal Bajo; George Luu; Samuel G Madamba; Paul Schweitzer; Loren H Parsons; Marisa Roberto Journal: Addict Biol Date: 2015-05-05 Impact factor: 4.280
Authors: Joanna Jacobus; Lindsay M Squeglia; Scott F Sorg; Tam T Nguyen-Louie; Susan F Tapert Journal: J Stud Alcohol Drugs Date: 2014-09 Impact factor: 2.582