Morphine increases intake of beer among rats.
Rats were maintained on a daily regimen of 22 h of water deprivation followed by a 2-h opportunity to take water and sweetened alcoholic beverage containing 12% ethanol. After 30 days, the alcoholic beverage was changed to beer containing either 3% or 6% ethanol. After 20 daily sessions with beer, they received, before the next session, an injection of saline. On the next day, they received a 1.0 mg/kg injection of morphine before the session. Morphine reliably increased rats' mean intake of both kinds of beer. Subsequently, the concentration of ethanol in each groups' beer was changed. The 3% group's beer was switched to 6%, and the 6% group's to 3%. Both groups altered their mean intake of beer in an apparent attempt to maintain intakes of nearly the same amount of ethanol, but presentation of 6% beer resulted in greater intakes of ethanol.
Nichols
M L
ML
Department of Psychology, Rensselaer Polytechnic Institute, Troy, NY 12180-3590.
Hubbell
C L
CL
Kalsher
M J
MJ
Reid
L D
LD
D000428:Alcohol Drinking; D000818:Animals; D001515:Beer; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D009020:Morphine