POTASSIUM FLUXES IN DESHEATHED FROG SCIATIC NERVE.
Desheathed frog (R. pipiens) sciatic nerves were soaked in Na-deficient solutions, and measurements were made of their Na and K contents and of the movements of K(42). When a nerve is in Ringer's solution, the Na fluxes are equal to the K fluxes, and about 75 per cent of the K influx is due to active transport. The Na content and the Na efflux are linearly related to the Na concentration of the bathing solution, while the K content and the K fluxes are not so related. When a nerve is in a solution in which 75 per cent of the NaCl has been replaced by choline chloride or sucrose, the active K influx exceeds the active Na efflux, and the K content is maintained. When a nerve is soaked in a solution that contains Li, the K(42) uptake is inhibited, and the nerve loses K and gains Li. When a Li-loaded nerve recovers in a Li-free solution, K is taken up in exchange for Li. This uptake of K requires Na in the external solution. It is concluded that the active transports of K and of Na may be due to different processes, that an accumulation of K occurs only in exchange for an intracellular cation, which need not be Na, and that Na plays a specific, but unknown, role in K transport.
D000818:Animals; D001001:Anura; D001692:Biological Transport; D001693:Biological Transport, Active; D007477:Ions; D008094:Lithium; D009186:Myelin Sheath; D011188:Potassium; D011194:Potassium Isotopes; D012106:Research; D012584:Sciatic Nerve; D012964:Sodium; D012965:Sodium Chloride; D014882:Water-Electrolyte Balance
D007477:Ions; D011194:Potassium Isotopes; D012965:Sodium Chloride; D008094:Lithium; D012964:Sodium; D011188:Potassium
EXPERIMENTAL LAB STUDY; FROGS; LITHIUM; MYELIN SHEATH; POTASSIUM; POTASSIUM ISOTOPES; SCIATIC NERVE; SODIUM; WATER-ELECTROLYTE BALANCE