Abstract
In our preceding paper (1) it was described that L-dopa is accumulated in brain slices against concentration gradient. An energy, dependent active transport . process, was assumed to be participated mainly in this phenomenon, and a possibility that Na+, K+ activated ATP-ase may be included in the process of active transport of amino acid was discussed.
It is generally known that ouabain causes a selective inhibition of active transport of cations across membranes of red blood cell, squid giant axon and others (2-4). Moreover, Na+, K+ activated ATP-ase is inhibited by low concentration of ouabain as reported by Skou (5) and Post (6). Therefore, it seems of interest to examine an effect of ouabain on the active transport of L-dopa.
On the other hand, it was reported by us that ouabain and protoveratrine caused a certain change in nerve cell membrane resulting in a decrease in potassium content of brain slices (7). In this connection, effect of protoveratrine is also examined in this paper.
Based on effects of these drugs on the active accumulation of L-dopa in brain slices, the activity of Na+, K+ activated ATP-ase and intracellular K+ concentration are proposed in this paper as factors to regulate the active transport of amino acids.
