Figure 2

D9ΔTrkB male and female mice display genotype- and sex-dependent differences in depression- and anxiety-like behaviors and in cocaine place preference. (a) In the forced swim test, male D9ΔTrkB mice had lower immobility scores versus male fB/fB, but there was no difference for females (*P < 0.05 fB/fB vs D9ΔTrkB males, N = 10-18/group). (b) In the elevated plus maze, male D9ΔTrkB spent a greater amount of time in the open arms versus male fB/fB, but there was no difference for females (*P < 0.05 fB/fB vs D9ΔTrkB males, N = 8-10/group). (c) Cocaine produced a larger place preference in D9ΔTrkB females versus fB/fB females (*P < 0.05, N = 7/group). Males showed a place preference for cocaine that was genotype-independent. fB/fB males showed a significantly greater place preference than fB/fB females (#P < 0.05, N = 7-8/group). (d) Acute cocaine, 20 mg/kg, increased activity in females of both genotypes (*p < 0.05, ***P < 0.001 saline versus cocaine, N = 5-6/group). Cocaine produced greater hyperactivity in female D9ΔTrkB mice versus fB/fB (### P < 0.001, N = 5-6/group). (e) Female mice were injected with saline or cocaine, 20 mg/kg, for 5 days. After a 6-day drug-free period, a cocaine challenge injection, 15 mg/kg, produced greater hyperactivity in D9ΔTrkB mice pretreated with cocaine versus fB/fB controls pretreated with cocaine (###P < 0.001, N = 5-6/group) In addition, D9ΔTrkB mice pretreated with cocaine showed greater hyperactivity in response to the cocaine challenge than did D9ΔTrkB mice pretreated with saline (**P < 0.01, N = 5–6), demonstrating that locomotor sensitization was greater in the D9ΔTrkB female mice.