In 6-OHDA mice, the density of the D1/D2 MSNs in the dorsal striatum was 3.8 ± 0.3 × 103 cells/mm3, accounting for 2.1 ± 0.2% of total MSN population. In comparison, the density of the D1 and the D2 MSNs was 108.2 ± 5.4 × 103 cells/mm3 and 94.9 ± 4.1 × 103 cells/mm3, representing 53.5 ± 1.0% and 44.4 ± 1.1% of the total MSN population, respectively (Fig. 3). There is no statistically significant difference between sham and 6-OHDA-lesioned animals in regard to these figures. Likewise, assessment of MSN densities in the Acb does not reveal any significant differences between the sham and 6-OHDA-lesioned animals (Fig. 3). The density of the D1/D2 MSNs obtained in the shell compartment of the Acb of 6-OHDA-lesioned mice was 29.7 ± 6.0 × 103 cells/mm3 whereas the neuronal density of D1 and D2 MSNs in the same experimental group were 193.1 ± 8.7 and 104.7 ± 5.7 × 103 cells/mm3, respectively. Values obtained in the core compartment of the Acb of 6-OHDA-lesioned mice reach 11.9 ± 1.4, 168.4 ± 13.8 and 102.9 ± 13.6 × 103 cells/mm3 for the D1/D2, D1 and D2 MSNs, respectively (Fig. 3).
