In spite of acute differences to the sedative and ataxic effects, motivation to drink as measured by operant self-administration of an oral ethanol solution remained unchanged in KO mice. The increased sensitivity to the motor effects of ethanol in the KO did not appear to affect the ability to obtain the solution since both genotypes self administered at a similar rate for all concentrations and neither genotype indicated an inability to perform due to inebriation. Importantly, the absence of a change in ethanol self-administration is consistent with previously published data using KO mice, which showed no differences in ethanol drinking preference as measured by a two-bottle choice paradigm [24]. However, a point mutation of the α2-subunit gave rise to varying effects on ethanol drinking depending on the precise test conditions, with the mutant drinking more alcohol during short-term daily access and less alcohol during continuous access [22]. Whilst these findings imply an involvement of the α2-subunit in ethanol drinking, they are difficult to interpret without further investigations of factors such as taste reactivity, withdrawal or motivational effects. Given the regional
