Ethanol state dependence involving a lever press response requirement in rats.

Previous studies have found that the timely completion of an FR10 schedule of food-rewarded lever pressing in rats demonstrates state dependence in drug-to-saline state changes with benzodiazepines and NMDA antagonists, but not with ethanol. We report here that, using sweetened condensed milk rather than food pellets as a reward, ethanol nonetheless produces a symmetrical state dependence with the lever press response requirement at doses that also impair acquisition. Extensive parametric studies are needed to unravel the apparently subtle conditions that govern the occurrence and features of the state dependence produced by various CNS compounds.