Effects of monovalent cations on (Na+ + K+)-ATPase in rat brain slices.
The influence of monovalent cations on membrane (Na + K+)-ATPase was estimated in vitro in intact cells from the oxygen consumption of rat brain cortical slices. High concentrations of K+, Rb+ or Cs+ stimulated the respiration in the presence of Na+. This stimulation was antagonized by ouabain in a concentration- and time-dependent manner. Additionally, only combinations of monovalent cations, that stimulate (Na+ + K+)-ATPase, increased oxygen consumption, indicating that the stimulated portion of respiration is realted to the (Na+ + K+)-ATPase activity. Low concentrations of Rb+ and Cs+, however, failed to affect oxygen consumption. Li+ slightly and transiently stimulated oxygen uptake at low concentrations and inhibited it at higher concentrations. Low concentrations of Tl+ also stimulated respiration in a K+-free medium. However, the inhibitory effects of Tl+ were predominant at higher concentrations or in the presence of K+. Thus, monovalent cations can alter (Na+ + K+)-ATPase activity. While Rb+ and Li+ produce opposite effects on this enzyme system under certain conditions, these actions do not seem to be related to the antidepressant action of Rb+ and the antimanic action of Li+.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology*; D002414:Cations, Monovalent / Q000494:pharmacology*; D002586:Cesium / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D012413:Rubidium / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013793:Thallium / Q000494:pharmacology; D013997:Time Factors
D002414:Cations, Monovalent; D002586:Cesium; D010042:Ouabain; D008094:Lithium; D013793:Thallium; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D011188:Potassium