ENERGY DEPENDENCE OF AMINO ACID UPTAKE IN BRAIN SLICES

1. (1) The effects of various inhibitors on the uptake of amino acids by mouse brain slices were determined. Cyanide was the strongest inhibitor among those tested. The inhibition of uptake produced by ouabain was fairly weak, as was that produced by lowering the level of Na+ of the medium, and by dinitrophenol. 2. (2) The combination of cyanide with other inhibiting conditions was additive for all the amino acids tested except lysine, arginine, leucine and valine; with dinitrophenol, the combination with other inhibiting conditions was additive for all the amino acids studied except lysine and α-aminoisobutyric acid. 3. (3) Part of the uphill transport of lysine, arginine, leucine and valine was cyanide insensitive; this part was also insensitive to the addition of other inhibitors. 4. (4) The degree of sensitivity to a decrease in energy supply was not the same for all the amino acids; it also varied with the inhibitors used. 5. (5) Some correlation for classes of amino acids existed in the sensitivity to a decreased energy supply, in that the small neutral and the acidic amino acids and GABA were more sensitive than were the large basic and the large neutral amino acids. © 1969.