Rat self administration of ethanol: enhancement by darkness and exogenous melatonin.
D000818:Animals; D001835:Body Weight; D002940:Circadian Rhythm; D003624:Darkness; D000431:Ethanol / Q000008:administration & dosage*; D008027:Light; D008550:Melatonin / Q000494:pharmacology*; D051381:Rats; D012646:Self Administration
D000431:Ethanol; D008550:Melatonin