Glass electrode measurement of net Na+ and K+ fluxes in erythrocytes of the spontaneously hypertensive rat.
The exchange of Na+ and K+ in rat red cells at 40% hematocrit incubated in a physiological salt solution containing 1 MM ouabain was monitored with ion-specific glass electrodes. Because this system measures a change in the activity of an ion as a logarithmic function of its preexisting level, delta[K+]o is more accurately measured than delta[Na+]o; within this limitation, the downhill ion movements were close to 1:1 over the temperature span from 37 to 3 degrees C. These transmembrane movements are reasonably well expressed in terms of first-order kinetics and an Arrhenius plot constructed for K+ as the accurate indicator of the exchange yields an activation energy of 12 kcal/mol. A well-defined reversal of the usual direct relation of temperature to exchange rate was observed between 6 and 3 degrees C. The net ion movements were distinctly faster at low temperature in cells from rats with spontaneous hypertension (SHR-Okamoto) than in cells from matched controls (Woodlyn and WKY).
D000818:Animals; D001692:Biological Transport; D001794:Blood Pressure; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D006973:Hypertension / Q000097:blood*; D007700:Kinetics; D008297:Male; D008839:Microelectrodes; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000097:blood*; D011199:Potentiometry; D051381:Rats; D012964:Sodium / Q000097:blood*
D010042:Ouabain; D012964:Sodium; D011188:Potassium