The effect of temperature on the content and turnover of sodium and potassium in rabbit nerve

Abstract

The contents and rates of turnover of the Na and K of rabbit nerve were studied at different temperatures. The Na content rises on storage at 0[degree], whereas at 18[degree] or 37[degree] the values are similar to those found in fresh nerve. This rise is associated with a decreased rate of efflux of Na. The Na of the tissue can be equilibrated with labeled Na, whereas the nerve K will only reach a total turnover of 36% at 18[degree] in saline solutions. Complete turnover can be obtained by the use of isotonic potassium phosphate solutions. The rate of entry of K is diminished by cooling to 0[degree], whereas the rate of efflux is accelerated. There is thus a considerable net loss of K. Half of this net loss is from the fraction which will turn over at 18[degree], and half from the fraction which does not.