Fig. 11.

Electron micrographs showing immunoreactivity for mGluR4a in the inner third of the dentate molecular layer (A, C, D) and in CA2 stratum oriens (B). Peroxidase (A, C, D) and immunogold (B) labeling for mGluR4a is found in presynaptic membrane specialization of asymmetrical synapses (A, B) on spines (s) and dendrites (Den) or symmetrical synapses (C, D) on dendrites (Den, D1). The labeled axon terminal (asterisk inD) in symmetrical synaptic contact with D1makes another unlabeled asymmetrical synapse on another dendrite (D2). T, Axon terminal. Scale bar, 0.5 μm.