Fig. 4.

Tf in axons is found in small vesicles. Hippocampal neurons were incubated for 20 min with Tf–HRP and processed for electron microscopy analysis. A, In semithick sections, dendritic (dendrites were identified by the presence of ribosomes and contacting presynaptic terminals) Tf–HRP-positive structures appear as large, endosomal-like structures (short arrow) and also as small vesicles (large arrows). B, C, Tf–HRP in axons. Tf–HRP is present in vesicles in both axonal shafts (B) and presynaptic varicosities (C). Scale bar, 1 μm.