DISTRIBUTION AND UPTAKE OF AMINO ACIDS IN VARIOUS REGIONS OF CAT BRAIN IN VITRO

—(1) The levels of the free amino acids were determined in five areas of the cat brain. The regional pattern was heterogeneous and fairly characteristic for each compound. (2) The uptakes of α‐aminoisobutyric acid, taurine, d‐aspartic acid, and l‐histidine were measured in incubated slices from 31 regions of the cat CNS. Differences in uptake were found among the various areas; the regional pattern of uptake was different for each amino acid. The initial rate of uptake (5 min incubation) very often paralleled the rate at equilibrium (90 min incubation). (3) The regional correlation between distribution in vivo and uptake in vitro was good for aspartate, less so for histidine, and poor for taurine. (4) It is concluded that regional heterogeneity in exit processes, available energy, cell density, or protein content is unlikely to have decisive influence in determining regional differences in distribution and transport of metabolites; it seems that influx is the most important factor. Copyright © 1969, Wiley Blackwell. All rights reserved