FIGURE 1.
NGF and olfactory system. (A) Sagittal view of the head with highlighted the area occupied by the nasal cavity. (B) Magnification of the nasal cavity with, in the square, the area occupied by the olfactory epithelium. (C) Cell composition of the olfactory part of the nasal cavity, mucosa, olfactory epithelium, and lamina propria. The olfactory epithelium is surrounded by layer globose and horizontal basal cells. It consists in many cellular types: sustentacular cells, Bowman’s glands producing mucus, immature olfactory neurons and mature olfactory sensory neurons that project their axons toward the olfactory bulb through the cribriform plate. Axons are enclosed by olfactory ensheating cells and olfactory nerve fibroblasts. The picture includes data on the expression of NGF, TrkA and p75NTR in the different cellular populations of the olfactory epithelium (from Feron et al., 2008).