Effects of unilateral hypoxia on neuroepithelial bodies in rabbit lungs

The present study was undertaken to investigate the influence of regional (unilateral) alveolar hypoxia on the intrapulmonary neuroepithelial bodies (NEB), which contain bioactive substances and are distinctly innervated. Eight (4-wk-old) rabbits were subjected to unilateral hypoxia. The animals were anesthetized by an intramuscular injection of Hypnorm and breathed spontaneously during the experiment. The right lung received a hypoxic gas mixture (10% O2-90% N2) and the left lung a hyperoxic mixture. Blood gas measurements indicated that no systemic hypoxemia or acidosis occurred under these conditions. Lung samples were examined by electron microscopy to determine morphometrically the extent of a secretory exocytosis at the basal cell pole of the NEB and by a microspectrographical analysis of the formaldehyde-induced fluorescence to quantify the NEB serotonin content. After 20 min of unilateral hypoxia the NEB in the right hypoxic lung exhibited an increased exocytosis and a lower serotonin content in comparison with the left hyperoxic lung NEB. These results indicate that NEB react to regional alveolar hypoxia by secreting serotonin and/or peptides to the surrounding lung tissue (blood vessels, smooth muscle, nerve endings, etc.).