Permeability of red-cell membrane to adenosine triphosphate (ATP) molecules during hemorrhagic shock.

The findings of decreased adenosine triphosphate (ATP) levels in liver, kidney, and other tissues of animals in hemorrhagic shock were the rationale for previous experimental attempts to improve cell function by administration of fluids that contained high concentrations of ATP. The beneficial effects of this resuscitation, which are still controversial, were attributed to cellular uptake of ATP--it was assumed that cell membranes are permeable to this substrate. The effect of a high concentration of ATP in extracellular medium on intracellular ATP content was studied by using red blood cells (RBCs) from rabbits in control (normal) and in hemorrhagic shock states. The glucose-depleted RBCs were incubated in medium with 5 mMol/L ATP, and their ATP concentration fell markedly to the same level as seen in glucose-depleted RBCs incubated without ATP. The decrease of ATP in glucose-repleted RBCs, incubated with or without ATP, also did not show any significant difference. Similar to parallel experiments that used normal RBCs, the high extracellular ATP content did not substantially affect the intracellular ATP concentration in RBCs from animals in shock. This study indicates that ATP molecules in extracellular medium cannot penetrate either the normal RBC membrane or the RBC membrane during shock.