Figure 1.

Genetic deletion of CB₂ receptors accelerates the onset of motor symptoms and increases their severity in a slowly progressing mouse model of HD. A, B, Deletion of CB₂ receptors increases the latency to cross and the number of slips of BACHD mice in a balance beam traversal assay at 3, 6, and 15 months. C, Deletion of CB₂ receptors decreases rearing activity in BACHD mice. Spontaneous locomotor activity was quantified in an automated open field and the numbers of rearings were scored for 30 min. Data represent the sum of total rearings in 30 min. A two-way ANOVA (p < 0.05) was performed in conjunction with post hoc t tests (significant p value adjusted for multiple comparisons with Bonferroni correction) to investigate the effects of time and genotype on rearing activity. D, Quantification of synaptophysin levels in the striatum at 15 months of age. One-way ANOVA was performed in conjunction with Dunnett's multiple-comparisons test. Values are means ± SEM; n = 25–30/genotype. *p < 0.05, **p < 0.01, ***p < 0.001.