DIFFERENCES IN FREE-CHOICE ETHANOL ACCEPTANCE BETWEEN TASTE AVERSION-PRONE AND TASTE AVERSION-RESISTANT RATS

Taste aversion (TA)-prone (TAP) and TA-resistant (TAR) rats were teste d for naive, nonforced acceptance of ethanol. Ethanol acceptance had p rayed no role in line development. Rather, the lines had been develope d via bidirectional, nonsibling matings based on susceptibility to dev elop cyclophosphamide-induced conditioned TAs to a 0.1% saccharin solu tion (at cyclophosphamide doses of 12.5 mg/kg for males and 15.0 mg/kg for females, ip). Rats from the 23rd selectively bred generations, wi th no prior exposure to ethanol, were given 24-hr access to a two-bott le choice between plain tap water and a solution of ethanol in water. Rats were initially given access to 1% ethanol in water, and the ethan ol concentration was increased by 1% every 3 days to a maximum of 10%. Ethanol consumption (g ethanol consumed/kg body weight) and preferenc e scores (volume ethanol solution consumed/total fluid intake) were de termined by daily bottle weighings. At 1% ethanol concentration, there were no differences between the rat lines in terms of ethanol consump tion or preference. At concentrations of 2 to 10%, TAP rats consumed l ess ethanol and showed a decreased preference for the ethanol solution s than TAR rats. Maximum ethanol consumption was reached at the 6% con centration for both lines. The mean (+/-SE) values of consumption at 6 % ethanol were 1.8 (+/-0.8) and 5.6 (+/-0.5) g of ethanol/kg body weig ht for TAP and TAR rats, respectively. Mean (+/-SE) preference scores at 6% ethanol were 26 (+/-12) and 76 (+/-6) for TAP and TAR rats, resp ectively. These findings indicate that differences in TA conditionabil ity may be associated with the propensity of rats to be high or low co nsumers of ethanol. Based on these data, it is hypothesized that high susceptibility for TA conditionability may deter many individuals from consuming the high levels of ethanol that usually precede alcohol tol erance and dependence.