Fig. 3.

GABAergic postsynaptic phenotype at striatal dopamine synapses. (A–C) Triple immunofluorescence for DAT (green) and VIAAT (blue), and for GABA_ARα1 (A, red), gephyrin (B, red), or NL2 (C, red). Note close apposition of GABA_ARα1, gephyrin, and NL2 clusters to both VIAAT⁺ GABAergic terminals (arrowheads) and DAT⁺ dopaminergic terminals (arrows). (D–F) Double-label postembedding immunoelectron microscopy for TH [Ø (diameter) = 15 nm] and for GABA_ARα1 (D, Ø = 10-nm colloidal gold particles), gephyrin (E, Ø = 10 nm), or NL2 (F, Ø = 10 nm). Immunogold particles (arrows) are concentrated at symmetric synapses formed by TH-labeled dopaminergic terminals (NT-DA, arrowhead pairs). (G–I) The density of immunogold labeling for GABA_ARα1 (G), gephyrin (H), or NL2 (I) per 1 μm of synaptic membrane at dopamine (DA), GABAergic (GABA), and glutamatergic (Glu) synapses. The specificity of NL2 labeling is confirmed by almost blank labeling in NL2-KO mice (I). Representative images of GABAergic synapses are shown in Fig. S3. Numbers of synapses analyzed are indicated above each column. Error bars represent SEM. *P < 0.05 and ***P < 0.001 (unpaired t test). [Scale bars: 2 μm (A–C) and 100 nm (D–F).]