Effect of ethanol on (R)- and (S)-salsolinol, salsoline, and THP in the nucleus accumbens of AA and ANA rats

Tetrahydroisoquinolines (TIQ) are active metabolites of dopamine. Intracere bral application stimulates the voluntary ethanol intake. In the present st udy, the levels of several TIQ's [(S)- and (R)-salsolinol, salsoline and te trahydropapaveroline (THP)] were measured in the extracellular space of the nucleus accumbens of alcohol-preferring AA and alcohol-avoiding ANA rats. Ethanol (2 g/kg i.p.) caused an increase in dopamine levels in ANA but not in AA rats. Neither (R)- nor (S)-salsolinol concentrations changed after et hanol application, though (S)-salsolinol concentrations were higher in ANA than in AA rats. Ethanol caused an increase in salsoline concentrations in ANA but not in AA rats. THP increased following ethanol, which tended to be stronger in ANA rats. The study revealed differences in the TIQ levels of the nucleus accumbens between AA and ANA rats. In case of changes following ethanol application (dopamine, salsoline, THP), the AA rats were less sens itive. The findings resemble observations in high-risk sons of alcoholics w ith reduced sensitivity to ethanol in young age and increased risk to becom e alcoholic. (C) 1999 Elsevier Science Inc. All rights reserved.