Fig. 9

CCK+ interneurons inappropriately innervate the striatum of Dag1^cKO mice. (a-d) Immunostaining for CB₁R (green) and Hoechst (magenta) shows minimal CB₁R innervation in the striatum of P30 (a) Dag1^Control;Bax^Control and (B) Dag1^Control;Bax^KO mice. Striatal innervation by CB₁R+ axons is abnormally increased in (c) Dag1^cKO;Bax^Control and (d) Dag1^cKO;Bax^KO mice. (e-g) Immunostaining for CB₁R (green) and Hoechst (magenta) in the striatum of Dag1^Control and Dag1^cKO mice at P10 (e), P15 (f), and P30 (g), showing that the inappropriate CB₁R innervation in the striatum of Dag1^cKO mice increases gradually between P10-P30. (h) Low magnification images (10X) of CB₁R+ cell bodies and their axons (Left panels, gray) near the cortico-striatal boundary from two separate Dag1^cKO mice at P30. Yellow boxed regions (right panels) show high magnification (20X) images of individual CB₁R+ cell bodies (arrowheads, green) and their axons projecting from the cortex into the striatum. White dotted lines (a-h) indicate the approximate boundary between the cortex and striatum. (i) Quantification of CB₁R pixels in the caudal striatum from P30 Dag1^Control (black bars) and Dag1^cKO (pink bars) mice shows increased CB₁R staining in Dag1^cKO (*P < 0.05, unpaired two-tailed Student’s t-test; n = 5 mice/genotype). Data are presented as mean values ± s.e.m.