The pulmonary neuroendocrine system: The past decade

The pulmonary neuroendocrine system consists of specialized airway endocrin e epithelial cells, associated with nerve fibres. The epithelial cells, the pulmonary neuroendocrine cells (PNEC), carl be solitary or clustered to fo rm neuroepithelial bodies (NEB). During the last thirty years, the pulmonar y neuroendocrine system has been intensively investigated and much knowledg e of its function has been obtained. This text reviews work which dates fro m the last ten years. in this period, the picture of the pulmonary neuroend ocrine system we previously had, has not fundamentally changed. The pulmona ry neuroendocrine system is still regarded as an oxygen sensitive chemorece ptor with local and reflex-mediated regulatory functions, and as a regulato r of airway growth and development. Continuing research has much more refin ed this picture. This text reviews several aspects of the pulmonary neuroen docrine system: phylogeny, the amine and peptide content of its epithelial cells, ontogeny and influence on lung development, the influence of hypoxia and nonhypoxic stimuli, immunomodulatory function, innervation and patholo gy. Among the discoveries of the past decade, three stand out prominently b ecause of their great significance: additional proof that the neural compon ent of the pulmonary neuroendocrine system is sensory, sound experimental e vidence that PNEC stimulate airway epithelial cell differentiation and the discovery of a specific membrane oxygen receptor in the PNEC.