Most of the work with these lines, covering many years, has been collated in a set of recent reviews (See Table 1) and one of us recently summarized that collection of reviews (Crabbe 2008). Some findings have emerged robustly across most or all pairs of selected lines. High drinking genotypes clearly have reduced serotonin function in limbic brain areas, accompanied by anatomical differences in this neurotransmitter system, but evidence for differences in several other transmitters have remained equivocal. Behaviorally, high drinkers consistently are shown to develop a greater degree of tolerance to alcohol's intoxicating effects and that tolerance is longer lasting. As serotonin is known to mediate some aspects of alcohol tolerance (Kalant 1998), these two results are consistent.
