Baseline striatal TrkB level and locomotor activity in D9ΔTrkB mice. (a) Baseline levels of striatal TrkB.FL and TrkB.T1 are equal in fB/fB male and female mice. Densitometric values were normalized to actin. Blot is representative of N = 6, p > 0.05 (t-test). (b) Relative to fB/fB, D9ΔTrkB male and female mice demonstrate approximately a 50% decrease in striatal TrkB.FL (N = 3–4,*** P < 0.005, t-test). There is a trend towards a small decrease in TrkB.T1 (N = 3, P = 0.06, t-test). Densitometric values were normalized to actin, and fB/fB levels were arbitrarily set to equal 1. (c) Down-regulation of striatal MSN TrkB.FL does not alter baseline total activity, but there is a genotype-independent increase in activity in female mice relative to males (N = 8-12/group, ** P < 0.01 two-way ANOVA for sex factor).