Dynamics of the neuroendocrine cell--regulatory peptide system in the lung. Specific overview and new results.
We assessed the changes in argyrophil neuroendocrine (NE) cell numbers, intensity of 5-HT fluorescence, and arterial medial thickness in the lungs of neonatal rabbits under various oxygen treatments. NE cell numbers and 5-HT fluorescence in normoxic rabbits increased from 12 hr before to 1 day after birth, and NE cells declined thereafter to the 10th day. In acute hypoxic (520 mm Hg for 2-2.5 hr) 5-day-old rabbits, 5-HT fluorescence was decreased, whereas NE cell numbers and medial thickness were unchanged. Neonates hypoxic from birth had higher NE cell numbers and increased medial thickness at 3 and 5 days, whereas 5-HT fluorescence was decreased compared with that in normoxic controls. These chronically hypoxic neonates showed a dramatic drop in argyrophil NE cell numbers to below normal when they were exposed to normoxia for 1 hr, but cell numbers and medial thickness returned to normal at 4 and 24 hr, respectively. We also tested the effect of acute and chronic hyperoxia: 100% O2 for 2-2.5 hr caused a significant drop in detectable NE cell numbers, whereas 40% O2 in N2 caused no change; chronic 40% O2 in N2 caused a fivefold increase in argyrophil NE cells by day 5, and medial thickness was below normal; 5-HT fluorescence decreased in acute 100% and chronic 40% hyperoxia and was elevated in acute 40% O2.
D001078:APUD Cells / Q000032:analysis / Q000166:cytology / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D004847:Epithelial Cells; D006728:Hormones / Q000032:analysis; D000860:Hypoxia / Q000473:pathology; D008168:Lung / Q000166:cytology* / Q000473:pathology; D010455:Peptides / Q000032:analysis; D011651:Pulmonary Artery / Q000473:pathology; D011817:Rabbits; D051381:Rats; D012701:Serotonin / Q000032:analysis; D012834:Silver; D013194:Staining and Labeling
D006728:Hormones; D010455:Peptides; D012701:Serotonin; D012834:Silver