Figure 3.

Ultrastructural Changes in the NAc in D1miRmGluR5 Mice

(A–F) Ultrastructural immunolocalization of CB1R, DAGLα, and MAGL in the NAc of wild-type (n = 3, A–C) and D1^miRmGluR5 (n = 3, D–F) mice assessed by preembedding silver-intensified immunogold method for electron microscopy. (A and D) CB1R immunoparticles (arrows) are distributed on perisynaptic and extrasynaptic membranes of axon terminals (ter) that make asymmetric synapses with dendritic spines (sp). (B and E) DAGLα immunolabeling is localized in dendritic spine membranes (arrows) away from the postsynaptic densities of asymmetric synapses. (C and F) MAGL shows a presynaptic and postsynaptic localization (arrows) on membranes of asymmetric presynaptic boutons and dendritic spines, respectively.

(G) Proportion of presynaptic and postsynaptic profiles labeled by each antibody for wild-type and D1^miRmGluR5 mutant mice. D1^miRmGluR5 mice have fewer excitatory synaptic terminals with CB1R but more postsynaptic elements with MAGL receiving asymmetric synapses than wild-type mice.

(H and I) Basal eCB concentrations of 2-arachidonoyl glycerol (2-AG, H) and anandamide (AEA, I) in the NAc are not affected in control (n = 10) and D1^miRmGluR5 mice (n = 10).

(J) Bath application of the cannabinoid agonist, CP55, 940, induces a dose-dependent inhibition of evoked fEPSPs recorded in the NAc synapses of wild-type mice, whereas in D1^miRmGluR5, there is a shift to the right of the dose-response curve.

Two-way ANOVA, (#) p < 0.05, (##) p < 0.0005 vs. wild-type. Scale bars 0.5 μm (A–G); picomoles or nanomoles/gram wet tissue +SEM (H and I).