Enhanced activity of the brain beta-endorphin system by free-choice ethanol drinking in C57BL/6 but not DBA/2 mice.
The objective of the present studies was to investigate the effect of voluntary ethanol consumption for 21 days on the brain beta-endorphin system of C57BL/6 (alcohol-preferring) and DBA/2 (alcohol-avoiding) strains of mice. As expected, C57BL/6 mice consumed a significantly higher quantity of the 10% ethanol solution than the DBA/2 mice. Under basal conditions the content of beta-endorphin like peptides differed only in the nucleus accumbens, higher levels being found in the DBA/2 mice. Voluntary ethanol consumption induced an increase in the hypothalamic content of mRNA coding for proopiomelanocortin, associated with a significant increase in the tissue content of beta-endorphin-like peptides in the arcuate nucleus and septum of the C57BL/6 mice, but did not alter the activity of the brain beta-endorphin system of the DBA/2 mice. Since voluntary ethanol consumption was not associated with nutritional deficits and stress, the ethanol-induced enhanced activity of the brain beta-endorphin system of the C57BL/6 mice must be a direct effect of ethanol and may be important in controlling the voluntary ethanol consumption by this strain of mice.
De Waele
J P
JP
Douglas Hospital Research Center, McGill University, Verdun, Québec, Canada.
Gianoulakis
C
C
D000428:Alcohol Drinking; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002755:Choice Behavior; D004195:Disease Models, Animal; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D001615:beta-Endorphin / Q000378:metabolism*
D012333:RNA, Messenger; D000431:Ethanol; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin