Restoration of the functions of the respiratory center in rats after total cold paralysis.

Abstract

White rats were cooled in water until respiratory arrest, which appeared at a brain temperature of 17.62 +/- 0.16 degrees C; animals were then removed from the water to a room at a temperature of 19-20 degrees C. Experimental animals were given 1 ml of 0.6% EDTA, which binds calcium ions, 1 min after the onset of respiratory arrest; controls received 1 ml of physiological saline. Electrical heaters were used to warm the medulla oblongata; respiratory recovery occurred at 6.0 +/- 0.3 min from the onset of respiratory arrest, when the medulla oblongata temperature was 18.62 +/- 0.15 degrees C. In controls, heating of the medulla oblongata to 18.84 +/- 0.17 degrees C did not restore respiration. EDTA bound calcium ions, facilitating transport of the excess quantities of these ions from the cell cytosol to the intercellular medium. Decreases in the cytosol calcium ion concentration to normal restored the normal regulation of metabolism in cells.