Journal of Applied Physiology, Vol 43, Issue 2 254-257, Copyright © 1977 by American Physiological Society
Effect of hyperbaric oxygen exposure on pulmonary clearance of 5-hydroxytryptamine
E. R. Block and A. B. Fisher
Clearance of 5-hydroxytryptamine (5-HT) by the lungs of normal and vitamin
E-deficient rats was evaluated following a 60-min exposure to 100% oxygen
(O2) at 4 ATA (HBO). After exposure, lungs were isolated, ventilated, and
perfused, with a recirculating system used for measurement of 5-HT
clearance. Control lungs were obtained from rats exposed to air at 1 ATA.
In control normal rats, fractional clearance of 5-HT was 0.78+/-0.03
(mean+/-SE). Following HBO 5-HT clearance was 0.55+/-0.04 (P less than
0.01). In control vitamin E-deficient rats. 5-HT clearance was 0.85+/-0.05
and was decreased to 0.46+/-0.03 (P less than 0.001) following HBO. To
evaluate the effect of recovery time after HBO on 5-HT clearance, separate
groups of rats were killed at varying intervals post-HBO. In normal rats,
5-HT clearance had returned to control levels by 3-4 after HBO; in vitamin
E-deficient rats, clearance remained unchanged 4 h after HBO and was only
74% (P less than 0.001) of control values 24 h post-HBO. These results
indicate that depression of pulmonary 5-HT clearance occurs in rats due to
hyperoxia and is potentiated by vitamin E deficiency. This represents a
reversible alteration of lung function which requires vitamin E for
complete recovery.
