Figure 3.

Cocaine-induced rearing and lateral movement on test days 1 and 7. As an additional analysis, we examined cocaine-induced activity by separately evaluating rearing and lateral movement. On test day 1, bHRs showed dramatically more cocaine-induced rearing (A) and lateral (B) movement compared to bLRs. Early life FGF exposure increased acute cocaine-induced rearing movement in both groups (A), and selectively increased cocaine-induced lateral movement in bHRs (B). On test day 7 (following a week of cocaine treatment), bHRs again showed greater sensitized rearing (C) and lateral movement (D) compared to bLRs. However, neonatal FGF2 treatment specifically impacted bLRs’ cocaine sensitization, leading FGF2-exposed bLRs to exhibit greater sensitized rearing and lateral movement compared to vehicle-exposed bLRs (C–D). We evaluated cocaine sensitization by comparing animals’ rearing (E) and lateral movement (F) on test day 1 versus 7. All bHR and bLR rats became sensitized to cocaine by day 7, showing enhanced cocaine-induced rearing and lateral movement on day 1 versus 7 (indicated by “a” versus “b” for bHR and “c” versus “d” for bLR). For cocaine-induced rearing behavior, neonatal FGF2-treated bHRs showed more rearing compared to all other groups, and neonatal FGF2-treated bLRs exhibited more rearing compared to vehicle-exposed bLRs (E). Similarly, for cocaine-induced lateral movement, neonatal FGF2-treated bLRs exhibited more lateral movement compared to vehicle-exposed bLRs (F). n=12 for each experimental group; *** indicates p<0.0001; ** indicates p<0.01; * indicates p<0.05