GENETIC DIFFERENCES IN THE EFFECTS OF VOLUNTARY ETHANOL CONSUMPTION ON BRAIN MONOAMINE LEVELS IN INBRED STRAINS OF MICE, C57BL/6J, C3H/He AND DBA/2Cr

This study was carried out to determine whether concentrationsof the brain monoamines noradrenaline (NA), dopamine (DA), and5-hydroxytryptamine or serotonin (5-HT) are different in threeinbred strains of mice (C57BL/6J, C3H/He and DBA/2Cr) knownto differ in their preference to alcohol, when they were givena free choice of 10% (v/v) ethanol and tap water to drink for4 weeks. Mice of these three strains showed mean ethanol intakesof 4.41, 1.76 and 0.77 g/kg/day respectively. Levels of theabove brain monoamines did not change in the alcohol-preferringC57BL/6J mice, but in those with less preference for alcohol,C3H/He and DBA/2Cr, there were significant increases in DA and5-HT levels respectively during the 4-week experiment. Thesefindings suggest that inbred strains of mice show genetic differencesof susceptibility to ethanol and that the strains with a lowpreference for alcohol undergo neurochemical changes after exposureto 10% ethanol and water even by free choice.