Figure 2.

Mecp2⁻ dopamine neurons in Mecp2^+/− mice (HET⁻) have a reduced dendritic arbor compared to Mecp2⁺ neurons from WT or Mecp2^+/− (HET⁺) female mice. A, Representative maximum intensity projection confocal images and tracings of neurobiotin-filled WT, HET⁺, and HET⁻ dopamine neurons from the SN of young and adult wild-type and Mecp2^+/− mice. B, The number of processes (dendrites and axon) on dopamine neurons decreased with age in wild-type and Mecp2^+/− mice, indicating a developmental pruning of dendrites. HET⁻ neurons had fewer dendrites than WT and HET⁺ neurons in young animals. There was no difference in the number of dendrites on WT and HET⁺ neurons. C, The total length of processes (in mm) decreased with age in wild-type and Mecp2^+/− mice. The total length of processes in HET⁻ neurons was significantly less than those in WT or HET⁺ neurons in both young and adult animals. There was no difference in the total length of processes in WT and HET⁺ neurons. D, The average process length (in μm) of WT and HET⁺ neurons was not different and did not change with age. Processes from HET⁻ neurons from adult Mecp2^+/− mice were significantly shorter than age-matched WT and HET⁺ neurons. Mean ± SEM; asterisk (*) designates statistical significance within age group; circle (°) designates statistical significance compared to young age.