COCAINE REWARD AND LOCOMOTOR-ACTIVITY IN C57BL 6J AND 129/SVJ INBRED MICE AND THEIR F1 CROSS/

Large individual differences exist among mice in their behavioral resp onses to drugs of abuse, and many of these differences have a substant ial genetic basis. The creation of new animal models using recombinant DNA technology has provided new genetic tools for assessing the role of specific candidate genes in drug response. This study presents a ch aracterization of cocaine activation and reward in the two strains use d most commonly for production of knockout mice, C57BL/6J and 129/SvJ, and their outcrossed F1 offspring. Using conditioned place preference , the study demonstrates that there are large strain differences in sp ontaneous locomotor activity and in the rewarding effects of cocaine. The 129/SvJ strain is hypoactive and is very sensitive to the locomoto r activating effects of cocaine but does not develop cocaine-condition ed place preference under conditions that yield significant place pref erence in C57BL/6J mice. These phenotypes are not inherited in a simpl e additive manner, but rather the F1 generation resembles the C57BL/6J progenitor strain for a number of the behaviors examined. (C) 1997 El sevier Science Inc.