Neurogenic influence on pulmonary surface tension and cholesterol in cats.

Previous work showed that stress involving the sympathetic nervous system via mechanical head injury and hyperbaric oxygen results in a decreased lung compliance and altered alveolar surfactants. Similar changes were associated with sympathetic nerve stimulation via the stellate ganglion. In view of reports that the minimum surface tension attained by lung wash fluid is increased by very small amounts of cholesterol content of the alveoli. The results show a nearly 200% increase in intra-alveolar cholesterol as well as high minimum surface tensions following sympathetic nerve stimulation. Such changes developed in the absence of any increase in lung wet wt/dry wt ratios. The results from the present study suggest that the previously reported decreased lung compliance and increased minimum surface tension associated with sympathetic stimulation may be due at least in part to contamination of the alveolar surfactants with large amounts of cholesterol.