Calcitonin gene related peptide immunoreactivity in rat lung: light and electron microscopic study.

Calcitonin gene related peptide immunoreactivity was investigated in the rat lung. Immunoreactive material was observed in nerve fibres surrounding bronchi, bronchioli, and blood vessels, and also in neuroendocrine cells and neuroepithelial bodies. In addition, the peptide was identified by immunoelectron microscopy in dense cored vesicles of granulated cells of the neuroepithelial bodies. These observations suggest that calcitonin gene related peptide plays a part in the regulatory function of the rat respiratory tract, exerting its influence by endocrine, paracrine, neurosecretory pathways, or a combination of these.