A scanning and transmission electron-microscopic study on neuro-epithelial bodies in the neonatal mouse lung

Neuro-epithelial bodies (NEBs) in the neonatal mouse lung have been studied by transmission (TEM) and scanning (SEM) electron microscopy. The TEM appearance of mouse NEBs are easily identified as island-like, half-spherical epithelial protrusions whose surface structure is obviously different from that of the surrounding ordinary respiratory epithelium. Their surfaces are devoid of ciliated cells and are covered by flattened, irregular contoured Clara cells and the apical surfaces of NEB cells. The latter are singly dispersed among the modified Clara cells, and the apical structure consists of characteristic microvillous projections. The SEM also reveals that most of the NEBs (86%) are preferentially located at the branching points of the intrapulmonary airways. The unique surface structure of NEBs, as well as their strategic location at the branching points of airways, gives support to the suggestion that NEBs might function not only as an intrapulmonary chemoreceptor, but also as a local endocrine organ regulating the air-flow and/or blood-flow dynamics in the specific peripheral region of the lung.