Chronic ethanol treatment potentiates ethanol-induced increases in interstitial nucleus accumbens endocannabinoid levels in rats.
We employed in vivo microdialysis to characterize the effect of an ethanol challenge injection on endocannabinoid levels in the nucleus accumbens of ethanol-naïve and chronic ethanol-treated rats. Ethanol (0.75 and 2 g/kg, i.p.) dose-dependently increased dialysate 2-arachidonoylglycerol (to a maximum 157 +/- 20% of baseline) and decreased anandamide (to a minimum 52 +/- 9% of baseline) in ethanol-naïve rats. The endocannabinoid clearance inhibitor N-(4-hydrophenyl) arachidonoylamide (AM404; 3 mg/kg) potentiated ethanol effects on 2-arachidonoylglycerol levels but did not alter ethanol-induced decreases in anandamide. AM404 alone did not alter dialysate levels of either endocannabinoid. Then, we characterized the effect of ethanol challenge on nucleus accumbens endocannabinoid levels in rats previously maintained on an ethanol-containing liquid diet. Ethanol challenge produced a greater and more prolonged increase in 2-arachidonoylglycerol (to a maximum 394 +/- 135% of baseline) in ethanol-experienced than in ethanol-naïve rats. The profile in ethanol-experienced rats was similar to that produced by AM404 pre-treatment in ethanol-naïve rats. AM404 in ethanol-experienced rats led to a further enhancement in the 2-arachidonoylglycerol response to ethanol challenge (to a maximum 704 +/- 174% of baseline). Our findings demonstrate that ethanol-induced increases in nucleus accumbens 2-arachidonoylglycerol are potentiated in animals with a history of ethanol consumption.
Alvarez-Jaimes
Lily
L
Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, USA.
Stouffer
David G
DG
Parsons
Loren H
LH
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism / Q000494:pharmacology; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism*; D002492:Central Nervous System Depressants / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids; D000431:Ethanol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005989:Glycerides / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D017551:Microdialysis / Q000379:methods; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D002492:Central Nervous System Depressants; D063388:Endocannabinoids; D005989:Glycerides; D000431:Ethanol; C094503:glyceryl 2-arachidonate; C107594:N-(4-hydroxyphenyl)arachidonylamide