EFFECTS OF ETHANOL ON PERIPHERAL BENZODIAZEPINE BINDING-SITES IN THE MOUSE CEREBELLUM AND BRAIN-STEM

[H-3]PK 11195 binding to the peripheral benzodiazepine binding site wa s investigated in the brain and liver of mice treated with ethanol (4 g/kg, p.o.) daily for 5 days. In the brain stem, B-max was decreased b y 78% in the ethanol-treated group with unaltered K-d (2 nM). The etha nol-withdrawn group did not differ from the control group in both para meters. In the cerebellum, B-max was decreased by 74% but the binding affinity increased 5-foId as the K-d decreased from 10 to 2 nM. The et hanol-withdrawn group did not differ significantly from the ethanol-tr eated group. No changes were observed in the cerebrum and liver. These results further support the idea that [H-3]PK 11195 binding may be a useful marker for ethanol consumption. The observed changes in these b inding sites may represent a functional adaptive response to the ethan ol insult and/or a role in the mediation of the effects of ethanol.