NPY-labeled perikarya with heavy inputs also commonly receive contacts from p75NTR-labeled terminals. A, In the infragranular hilus, a p75NTR-IR axon terminal (p75-T) establishes an asymmetric synapse (curved arrow) with an NPY-IR soma (NPY-SO). Many unlabeled axon terminals (UT) also synapse on this perikaryon (open curved arrows). B, Higher magnification view of a portion of an NPY-labeled perikaryon contacted by a p75NTR-IR axon terminal (p75-T) and numerous unlabeled terminals (UT) (solid curved arrows andopen curved arrows, respectively). Scale bars:A, 1.0 μm; B, 0.5 μm.