Retrograde transport of FG into striatum is slow in mice expressing mhtt. (A) Injection scheme for FG uptake. FG was injected into substantia nigra, and uptake in striatum was monitored with time. (B) Quantification of the number of neurons that accumulate FG in the cell bodies in control and HD72 mice 1 and 3 days after the injection. Horizontal lines represent 0, 50, 100, etc. cells labeled/mouse. Black bars, control FVB/N mice; white bars, HD72 mice; *, P < 0.01 (t test). (C) Retrograde uptake of FG in striatum of control mice 3 days after the injection. The box indicates the area in the striatum that was used for quantification in panel B. Scale bar, 200 μm. (D) View of cortical neurons with FG accumulation in the cell bodies. Scale bar, 50 μm. (E, F) FG uptake in the striatum of control (E) and HD72 (F) mice 1 day after the injection. Neuronal cell bodies labeled with FG are seen as bright circular structures in tissue. Scale bar, 50 μm.