288 E. ROBERTS AND D. G. SIMONSEN 
(GABA) which appears to have a unique occurrence in the central nervous sys- 
tem (see ref. 12). Other constituents which have been detected on chromatograms 
of alcoholic extracts of brain and spinal cord have also been found to occur in 
varying concentrations in the other tissues. A recent survey of 32 areas of monkey 
brain has also revealed regional differences in distribution of ninhydrin-reactive 
constituents. However, only minimal differences were apparent when different areas 
i 

w- @& * or 
Tees a”. 
Figs. 17-22. Chromatograms of extracts obtained from 20 mg of original fresh weight of 
different areas of rat brain; Fig. 17: corpora quadrigemina. Fig. 18: diencephalon. Fig. 19: 
cerebral hemispheres. Fig. 20: pons and medulla. Fig. 21: cortex. Fig. 22: cerebellum. Taurine, 5; 
Db D5 5D 2 } 
serine, 10; glycine, 14; y-aminobutyric acid, 22. 
of cortical gray matter were compared with each other. Some recent values have 
been published (Table I) for various areas of human brain determined by column 
chromatography?’ and for areas of brains of other species): 1°. 
WHAT IS THE INTRACELLULAR DISTRIBUTION OF THE FREE AMINO ACIDS? 
The various tissues contain much greater concentrations of a number of the detect- 
able constituents than are found in whole blood or plasma. The intracellular patterns 
do not reflect the composition of the plasma. The exact mode of intracellular reten- 
tion of large amounts of easily extractable amino acids and other compounds is not 
References p. 348/349 
