Glutamate immunoreactive PRV-labeled neuron in the AIN 4.5 d after injection into the OOM. Glutamate immunoreactivity is shown in the top left panel. Note a large glutamate-immunoreactive neuron at the bottom of the panel indicated by the asterisk. GABA-immunoreactivity is shown in the top middle panel. Four GABA-immunoreactive interneurons are visible and note the presence of glutamate immunoreactivity in their cell bodies. Numerous GABA-immunoreactive terminals are evident apposed to different neuronal processes and glutamate-immunoreactive somas. Glycine-immunoreactivity is shown in the top right panel. Note a small interneuron that is exclusively glycine-immunoreactive. A few glycine-immunoreactive terminals apposing dendrites and somas of glutamate-immunoreactive and GABA-immunoreactive neurons are shown. A PRV-labeled neuron is shown in the bottom left panel. A merged image of glutamate-, GABA-, and glycine immunoreactivity and PRV is shown in the bottom right panel. Note that the PRV-labeled neuron colocalizes with a large glutamate-immunoreactive neuron. A small interneuron immunoreactive for both GABA and glycine is also shown. Glu, Glutamate; Gly, glycine. Scale bar, 40 μm.