Jc. Froehlich et al., CONTRIBUTION OF THE OPIOID SYSTEM TO ALCOHOL AVERSION AND ALCOHOL-DRINKING BEHAVIOR, The Journal of pharmacology and experimental therapeutics, 287(1), 1998, pp. 284-292
The effect of blocking delta opioid receptors on alcohol aversion was
examined in female alcohol-preferring (P) rats using a conditioned tas
te aversion (CTA) paradigm. In experiment 1, alcohol naive P rats were
given i.p injections of 0.5, 1.0 or 1.5 g alcohol/kg BW or saline, pa
ired with consumption of a banana-flavored solution during 5 condition
ing trials. Alcohol in a dose of 0.5 g/kg was not aversive while the t
wo higher doses (1.0 and 1.5 g/kg) were both aversive in the CTA parad
igm. In experiment 2, the effect of the selective delta opioid recepto
r antagonist, naltrindole (NTI), on alcohol aversion was examined. Rat
s were pretreated with NTI in doses of 2.5, 5.0, 10.0 or 20.0 mg/kg be
fore conditioning using the nonaversive dose of alcohol from Experimen
t 1. As in experiment 1, the 0.5 g/kg dose of alcohol did not produce
a CTA. Administration of NTI alone in doses of 2.5, 5.0 or 10.0 mg/kg
did not produce a CIA. However, when the nonaversive dose of alcohol (
0.5 g/kg) was combined with NTI in a dose of either 5.0 or 10.0 mg/kg,
an aversion to alcohol was seen. The highest dose of NTI (20 mg/kg) p
roduced a CTA when given either alone and in combination with alcohol.
The results indicate that blocking the action of opioid peptides at t
he delta opioid receptor can make a nonaversive dose of alcohol aversi
ve which suggests that opioid peptides, acting via the delta opioid re
ceptor, play an important role in regulating alcohol aversion.