Correlative analysis of ethanol-related phenotypes in rat inbred strains

As a summary presentation of the ethanol-related traits in the rat inbred strains, the responses to ethanol for various traits of the eight strains were analyzed. The intercorrelations among the means of the strains were computed and the interrelationships among the strain correlations were determined further by partial correlation and factor analysis. Sources of data on strain ethanol response included measures from laboratories of Drs. Deitrich, Li, Erickson, Pohorecky, and Tabakoff, who have participated in this joint study on the development of the rat heterogeneous stock (N/Nih). Although there are problems with estimating strain correlations from data collected in different laboratories, some informative associations among the ethanol-related traits were apparent. Genetic variation for behavioral and physiological responses to ethanol was indicated by the inbred strain distribution. The strains clearly differed in response to ethanol, with the mean of the National Institutes of Health stock falling intermediate within the range of the inbred strain distribution. For the ethanol-related traits considered jointly, an association between initial behavioral sensitivity, ethanol intake, and metabolism, as well as an association between development of tolerance, initial sensitivity, and several physiological measures, was suggested. Thus, the rat heterogeneous stock, a systematically outbred population, should provide a useful animal model with which to study the physiological basis for ethanol intake and preference, response to acute ethanol, and the development of tolerance.