Lack of cocaine-conditioned place preference in DAT knockout mice with
no or one copy of the SERT gene. (Upper) Conditioned
place preference induced by 10 mg/kg of cocaine in mice of several
genotypes (n, 8–56). Time scores shown represent
differences between post- and preconditioning time spent in the
cocaine-paired environment. DAT knockout mice with no or one copy of
SERT displayed no preference for the places associated with 10 mg/kg
of cocaine. *, P < 0.05 vs. saline. Average
initial preference for the nonpreferred side for all groups was between
37 and 45%. (Lower) Conditioned place preference
induced by 10- and 20-mg/kg of cocaine doses in mice of several
genotypes (n, 8–56). Time scores shown represent
differences between post- and preconditioning time spent in the
cocaine-paired environment. Wild-type mice and SERT knockout mice with
one copy of DAT displayed significant preferences for the place
associated with either 10 or 20 mg/kg of cocaine, but double knockout
mice did not have a significant preference for places associated with
either dose. *, P < 0.05 vs. saline.