[abstract] FUNCTIONAL ABNORMALITIES OF RED CELL CAUSED BY HYPERBARIC INERT GASES.

Abstract

Suspensions of human red blood cells are exposed to hyperbaric inert gases and hemoglobin-oxygen equilibria are determined under pressure by a new, dynamic method. Increasing partial pressures of nitrogen (up to 100ATA) produce increased oxygen affinities of the erythrocyte hemoglobin. These affinity changes are accompanied by changes in the shape of the oxygen binding curves, indicating a gradual loss of cooperativity in the hemoglobin molecule. In addition, the 2,3-diphosphoglycerate concentration in red cells limits the magnitude of the inert gas effect. So does the chemical nature of the hyperbaric inert gas which renders helium less effective than nitrogen. The observed changes in hemoglobin-oxygen affinity are completely reversible and are not associated with any discernible changes in red blood cell structure. The formation of gas hydrates of the clathrate type is a likely chemical mechanism by which hyperbaric gases could produce the observed results. Such structures would involve both water and functional groups of the hemoglobin subunits which have a stabilizing effect and their formation would result in an abnormal molecular function.