Neural cell adhesion molecules are present in the fetal human primary olfactory pathway.

Olfactory tissues from human fetuses (17.5-28 weeks of gestation) were stained by immunofluorescence for neural cell adhesion molecules (N-CAMs). Staining for N-CAMs was most prominent in the olfactory nerve bundles in the lamina propria, while in the olfactory epithelium, it was present on the olfactory receptor neurons and globose basal cells. The basal cells proper and supporting cells lacked N-CAMs. In the olfactory bulb, only the olfactory nerve and glomerular layers showed moderate labeling for N-CAMs. Western blot analysis showed that the N-CAMs of the fetal human primary olfactory pathway consisted of three molecular isoforms, N-CAM180, N-CAM140 and N-CAM120.