Figure 2.

(a–c) Micrographs of a vertical cryostat section through rat retina. (a) Nomarski micrograph showing the retinal layers (ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer; IPL, inner plexiform layer; GCL, ganglion cell layer). (b) Retina section stained with the antiserum against mGluR8. The antiserum is directed against the carboxyl-terminal end of the receptor, which is located intracellularly. Immunofluorescence is present in both synaptic layers, the IPL and the OPL, and in somata of cells in the INL and GCL. (c) Control; the anti-mGluR8 antiserum was preadsorbed with the antigen, resulting in a complete loss of specific immunoreactivity. (d) Electron micrograph showing the presynaptic localization of mGluR8 immunoreactivity in rod spherules. The presynaptic ribbon in the rod spherule is marked by an arrowhead. Postsynaptic processes are marked by stars. (e–g) Double labeling of isolated photoreceptors with an antibody against arrestin (e) and the antiserum against mGluR8 (f). (g) Nomarski micrograph showing the isolated cells. (Bars = 30 μm in c for a–c; 0.2 μm in d; and 10 μm in g for e–g).