Fig. 6.

The critical period for D2R to regulate dendritic spine number and reversal of the spine deficiency by antipsychotics treatment in sandy mice. Hippocampal slices for diolistic labeling were prepared from C57BL/6 mice of various ages intraperitoneally injected with vehicle or with the D2R agonist 0.5 mg/kg of quinpirole (a, b), sandy mice and their wild–type littermates of various ages (c, d), or sandy mice and their wild–type littermates at 3 weeks of age intraperitoneally injected with vehicle, 5 mg/kg of loxapine or 8 mg/kg of clozapine (e, f). Representative images of DiI–labeled basal dendrites of hippocampal CA1 neurons are shown in (a, c, e). Quantification of spine density is shown in (b, d, f). 15 neurons from 3 slices of each animal were imaged and analyzed. n = 3 mice for each condition. Scale bar, 5 μm. Data are presented as mean ± SEM. Mann–Whitney test was used for comparison between wild–type and sandy mice in (b, d), and between vehicle and drug treated mice of the same genotype in (f).