This video demonstrates an electron microscopy technique for visualizing neurotransmitter receptor localization in retinal synapses. The retinal sections contain retinal ganglion cells that exhibit membrane-bound neurotransmitter receptors and are labeled with cholera toxin subunit B (CTB). Upon labeling the markers with gold nanoparticle-conjugated antibodies and counterstaining the section with heavy metals, the RGC receptors are visualized under a microscope.