Effect of Nicotinic Acid on Anoxia in Rats

Abstract

Summary

Rats treated with nicotinic acid or its amide were found to survive until they reached a barometric pressure of 75 mm Hg (equivalent altitude, 53,800 feet); untreated controls died at an average pressure of 93 mm Hg (49,275 feet). Statistically, the differences are probably significant.

The tachypnea developing at low barometric pressure is much less in treated than in untreated rats. Preliminary injection of 1 mg nicotinic acid was followed by an increase in respiratory rate of only 22% at 300 mm Hg as opposed to approximately 80% in untreated controls. Differences of comparable magnitude were noted at pressures of 300 and 250 mm Hg following the administration of nicotinamide. Statistical analyses indicate that these differences are highly significant.