ABSTRACT
The pulmonary neuroendocrine cell (PNEC) is a cell type in the airway epithelium with endocrine and neural-like features. It appears solitary or in innervated clusters, called neuroepithelial bodies (NEBs). PNECs produce several bioactive molecules such as serotonin (5-hydroxytryptamine, 5-HT), calcitonin gene-related peptide and bombesin. Several lines of evidence suggest that PNECs have important functions. During fetal life, PNECs may be involved in regulation of lung development and, after birth, they may modulate immune function and participate in airway epithelial repairing. In addition, their airway chemoreceptor properties may, via a reflex mechanism, be important for regulation of respiratory and cardiac frequencies and blood pressure and, locally, for control of pulmonary blood flow and bronchomotor tone. It has conclusively been shown that solitary PNECs are able to control the spontaneous airway contraction in guinea pigs. Pathological changes in PNECs may be of importance in several lung diseases including asthma and chronic obstructive pulmonary disease.
