Classification of LCRs and HCRs and kinetic analysis of DAT-mediated uptake in striatal synaptosomes prepared 25 min post-cocaine from these rats. A Distribution of baseline and the initial 20 min of cocaine-induced locomotor activity in rats subsequently classified as either LCRs or HCRs (bars). The solid horizontal line represents this group’s median cocaine-induced locomotor activity. B Representative results for specific [3H]DA saturation uptake for an LCR, HCR and veh-treated rat, assayed on the same day, in the presence of 0.5 nM [3H]DA and increasing concentrations of unlabeled DA (0, 5 nM, 10 nM, 50 nM, 0.1 μM, 0.5 μM, and 1 μM). C [3H]DA uptake Vmax values for all LCRs (n = 8) and HCRs (n = 8) presented as a percentage of their respective veh-treated control. D Correlation of distance traveled 20 min post-cocaine and Vmax values at 25 min post-cocaine for all cocaine-treated rats. Bars in (A) and (C) are means ± SEM. ★★★ p < 0.001, LCR vs. HCR.