Prolonged sympathetic activation and pulmonary surfactant: absence of effect in anesthetized cats

Cats were anesthetized with either sodium pentobarbital or ketamine hydrochloride, paralyzed, and artifically ventilated. The stellate ganglion was electrically stimulated for one hour (10 V, frequency = 10 per sec, and 0.5 to 1.0 msec pulse duration), alternating periods of stimulation and rest of 20 sec each, while control animals were sham operated. After stimulation, static deflation pressure-volume relationships of the excised lungs were compared. Regardless of the anesthetic used, no change in static lung compliance was found between experimental and control groups, and one hour of stellate stimulation did not produce significant changes in lung volumes at maximum distending pressures, in lung weight/body weight ratios, or in minimum surface tension measurements of lung extracts. We concluded that prolonged intermittent stimulation of the stellate ganglion does not alter significantly the function of alveolar surfactant.