THE NEUROBIOLOGY OF ALCOHOLISM IN GENETICALLY SELECTED RAT MODELS

Rats selectively bred for their tendency to drink large or small quant ities of alcohol are a useful model for investigators examining the po ssible neurobiological processes underlying alcoholism. Studies with t he alcohol-preferring (P) and alcohol-nonpreferring (NP) and the high- alcohol-drinking (HAD) and low-alcohol-drinking (LAD) pairs of rat lin es developed at Indiana University have illustrated differences in sev eral behavioral and neurobiological characteristics associated with al cohol consumption. Specifically, compared with alcohol-avoiding rats, rats with an affinity for alcohol have a greater sensitivity to the st imulatory effects of low to moderate doses and a reduced sensitivity t o the negative effects of high doses, Rats that voluntarily drink larg e quantities of alcohol also acquire tolerance to alcohol's aversive e ffects, In addition, these rats differ from their alcohol-avoiding cou nterparts in the levels of several chemical mediators (i,e,, neurotran smitters) found in the brain, including serotonin, dopamine, gamma-ami nobutyric acid (GABA), and the endogenous opioids.