AJP - Cell Physiology, Vol 244, Issue 5 313-C317, Copyright © 1983 by American Physiological Society
Hemolytic action of potassium salts on dog red blood cells
J. C. Parker
Recent demonstrations of chloride-associated passive potassium movements in
red blood cells of humans, ducks, sheep, and toadfish prompted a
reinvestigation of potassium permeability in dog red blood cells. Early
observations of Davson (J. Physiol. London 101:265-283, 1942) had shown
that replacement of chloride by nitrate and thiocyanate caused a greatly
increased rate of potassium flux across the dog red cell membrane. This
finding seemed at variance with results in other species in which chloride
replacement caused a fall in potassium flux. The present data indicate that
passive potassium movements in swollen dog red blood cells are chloride
dependent and furosemide sensitive, as shown for the cells of other
species. Davson's findings were demonstrated to be due to the inclusion of
small quantities of calcium in the medium under circumstances that favored
calcium entry into the cells, thus opening the calcium-activated potassium
channel described by Gardos (Curr. Top. Membr. Transp. 10:217-277, 1978 and
Nature London 279:248-250, 1979). Potassium movements through the latter
channel were stimulated when chloride was replaced by more permeant anions,
such as nitrate and thiocyanate, which also increased the rate of net
potassium movements in valinomycin-treated cells.
