Selective breeding for alcohol preference and associated responses.

Selective breeding for high and low alcohol-drinking preference has produced rat lines useful for studying the nature of excessive alcohol-seeking behavior. Compared with the alcohol-nonpreferring line, the preferring animals exhibit heightened responsivity to the low-dose activating effects of ethanol as well as enhanced capacity for developing tolerance to the aversive, behaviorally impairing effects of ethanol. The preferring animals exhibit lower brain serotonin and dopamine neurotransmitter activity as well as differences in other neurotransmitter neuromodulator systems, compared with the alcohol-nonpreferring animals.