Effects of food availability and administration of orexigenic and anorectic agents on elevated ethanol drinking associated with drinking in the dark procedures.
BACKGROUND
Drinking in the dark (DID) procedures have recently been developed to induce high levels of ethanol drinking in C57BL/6J mice, which result in blood ethanol concentrations reaching levels that have measurable affects on physiology and/or behavior. The present study determined if increased ethanol drinking associated with DID procedures may be motivated by caloric need rather than by the postingestive pharmacological effects of ethanol. To this end, food availability was manipulated or mice were given peripheral administration of orexigenic or anorectic agents during DID procedures.


METHODS
C57BL/6J had 2-hours of access to the 20% (v/v) ethanol solution beginning 3-hours into the dark cycle on days 1 to 3, and 4-hours of access to the ethanol bottle on day 4 of DID procedures. In Experiment 1, the effects of food deprivation on ethanol consumption during DID procedures was assessed. In Experiments 2 and 3, mice were given intraperitoneal (i.p.) injection of the orexigenic peptide ghrelin (0, 10 or 30 mg/kg) or the anorectic protein leptin (0 or 20 microg/g), respectively, before access to ethanol on day 4 of DID procedures. In Experiment 4, hourly consumption of food and a 0.05% saccharin solution were assessed over a period of hours that included those used with DID procedures.


RESULTS
Consistent with previous research, mice achieved blood ethanol concentrations (BECs) that ranged between 100 and 150 mg% on day 4 of DID experiments. Neither food deprivation nor administration of orexigenic or anorectic compounds significantly altered ethanol drinking with DID procedures. Interestingly, mice exhibited their highest level of food and saccharin solution consumption during hours that overlapped with DID procedures.


CONCLUSIONS
The present observations are inconsistent with the hypothesis that C57BL/6J mice consume large amounts of ethanol during DID procedures in order to satisfy a caloric need.
Lyons
Angela M
AM
Department of Psychology, Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, North Carolina 27599-3270, USA.
Lowery
Emily G
EG
Sparta
Dennis R
DR
Thiele
Todd E
TE
D000428:Alcohol Drinking / Q000503:physiopathology*; D000437:Alcoholism / Q000503:physiopathology; D000818:Animals; D001067:Appetite Depressants / Q000008:administration & dosage / Q000494:pharmacology*; D019167:Appetite Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D003624:Darkness; D004195:Disease Models, Animal; D002149:Energy Intake / Q000187:drug effects / Q000502:physiology; D000431:Ethanol / Q000097:blood; D005247:Feeding Behavior / Q000187:drug effects; D005508:Food Deprivation / Q000502:physiology*; D054439:Ghrelin / Q000008:administration & dosage / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D020738:Leptin / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012439:Saccharin / Q000378:metabolism
D001067:Appetite Depressants; D019167:Appetite Stimulants; D054439:Ghrelin; D020738:Leptin; D000431:Ethanol; D012439:Saccharin
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