Intracellular sodium and potassium changes in vascular smooth muslce during hemorrhagic shock

The vascular smooth muscle cell sodium and potassium changes occurring in hemorrhagic shock were studied in rats subjected to hemorrhagic shock at 30 millimeters of mercury for a two hour period. A new ion exchange method, based upon the substitution of lithium for extracellular sodium was used to measure the intracellular sodium and potassium. A significant rise in cell sodium and fall in cell potassium levels occurred. These changes suggest that vascular smooth muscle cell membrane function is impaired in hemorrhagic shock. The normal homeostatic vascular responses to hemorrhage may be significantly affected by these changes.