Ethanol-induced changes of dopaminergic function in three strains of mice characterized by a different population of opiate receptors.

The effects of ethanol have been studied in three strains of mice (DBA 2J, albino, and C57 BL/6J) having different populations of opiate receptors. Acute ethanol treatment induces a significant increase in striatal dopamine metabolism only in the mouse strains (C57 and albino) that are rich in enkephalinergic receptors upon nigrostriatal dopaminergic fibers. After chronic ethanol, the same strains develop tolerance to striatal dihydroxyphenylacetic acid increase, while the striatal dopaminergic recognition sites become supersensitive. DBA mice, which have lower numbers of enkephalinergic receptors and higher levels of enkephalins in the striatum, fail to show changes in central dopaminergic function after acute or chronic ethanol treatment. Our results indicate the importance of an interaction between ethanol and opiate receptors in determining the neurochemical and behavioral effects of ethanol.