The effect of vagotomy and hydrocortisone administration on pulmonary surfactant activity in adult albino rats.

The role of vagus and hydrocortisone in the regulation of lung surfactant was studied in adult albino rats. Dynamic surface tension and phospholipid content were measured in the lung wash for estimating surfactant activity. The results indicate that vagotomy significantly decreases the surfactant activity whereas hydrocortisone does not alter it. But when hydrocortisone was administered prior to vagotomy it could prevent the decrease in surfactant activity. Thus it is concluded the regulation of lung surfactant in the adult lung is mainly by vagus nerve and hydrocortisone as such has no role but in the absence of vagal regulation hydrocortisone could maintain normal lung surfactant activity.

Cardiovascular effects of acetaldehyde in guinea pigs.

The hemodynamic effects of intravenous administration of acetaldehyde were determined in anesthetized control (group I), propranolol pretreated (group II) and phentolamine pretreated (group III) guinea pigs. Acetaldehyde produced an immediate and significant increase in mean arterial pressure followed by its progressive decrease resulting in hypotension. Heart rate increased significantly. In propranolol treated animals, acetaldehyde-induced tachycardia was not produced whereas in phentolamine treated animals, the initial pressor response was converted into a depressor one. Hence the increase in mean arterial pressure and heart rate produced by acetaldehyde are likely to be due to catecholamine release from adrenergic nerve endings.