Genetic differences in the operant rate-depressant effects of ethanol between four inbred mouse strains

The use of genetically defined populations in studies of ethanol on schedule-controlled behavior can help determine genetically covarying responses to ethanol as well as the role of environmental constraints in the expression of gene effects. The purpose of the present study was to investigate the rate-depressant effects of ethanol in four inbred mouse strains, A/J, CBA/J, C3H/HeJ and DBA/2J. Ethanol dose-dependently decreased high rates of behavior maintained by fixed-ratio responding far water in all four strains. In general, DBA/2J mice were the least sensitive to the rate-depressant effects of ethanol, with an ED(50) averaging 19-29% greater than the other three inbred strains. The results of this experiment demonstrate that genetic factors play a role in determining responsivity to even a complex learned behavioral sequence such as lever press responding under a fixed-ratio schedule, and that sensitivity to the effects of ethanol on fixed-ratio responding for water is not genetically related to acute narcotic effects or reinforcing effects of ethanol.