FREE AMINO ACIDS IN BRAIN 469 
excretion, reflecting levels throughout the rest of the body, falls markedly. Hope 
noted considerable variations between animals. There is a wide scatter of values in 
the present series and it is not possible to discern any changes in concentration after 
administration of the various drugs. Although OkuMuURA ef al. noted increases 
under a variety of conditions, indicating a rather non-specific effect, others have 
reported no changes in taurine after convulsive hydrazides", ammonia poisoning® 
and ethanol*°. 
In conclusion, it can be stated that the psychotropic drugs studied in the present 
work have but slight effect on the overall pattern of brain amino acids. The changes 
in concentration that do occur, in GABA, GPE, and possibly in acetylaspartic acid, 
are not correlated with the pharmacological actions of these drugs. A survey of 
previously reported experiments of this type also fails to reveal a consistent picture 
of drug effects on brain amino acids. The effects of the psychotropic drugs are to be 
sought in subtler aspects of brain metabolism; the alterations these drugs induce 
in the concentration of some amino acids are more likely by-products of a chain 
of metabolic reactions. 
ACKNOWLEDGEMENTS 
It is a pleasure to acknowledge the assistance, at various stages of this work, of 
Mrs. C. McCannon, Mrs. S. A. JOHNSON, and Mrs. YUN-OK SUH. 
Compounds were generously supplied by Geigy Pharmaceuticals (Tofrani 
imipramine Geigy), Smith Kline & French Laboratories (Thorazine®, chlorprom- 
azine SKF), and Ciba Pharmaceutical Products, Inc. (Serpasil®, reserpine Ciba). 
]8 
REFERENCES 
1D. H. SpackMAN, W. H. STEIN AND S. Moore, Anal. Chem., 30 (1958) 1190. 
2 N. OxkumuRa, S. OtsuKI AND H. Nasu, J. Biochem. (Tokyo), 46 (1959) 247. 
3G. J. Wricut, F. Navazio anD M. K. Horwitt, Federation Proc., 20 (1961) 323. 
4 FE. Roperts, in E. Roperts, Inhibition in the Nervous System and y-Aminobutyric Acid, Perga- 
mon, New York, 1960, p. 144. 
C. F. BAXTER AND E. RosBerts, Proc. Soc. Exptl. Biol. Med., tot (1959) 811. 
6 C. F. BAXTER AND E. Roserts, Proc. Soc. Exptl. Biol. Med., 104 (1960) 426. 
E. EIDELBERG, C. F. BAXTER, E. RoBerts, C. A. SALDIAS AND J. D. FRENcH, Proc. Soc. Expill. 
Biol. Med., tor (1959) 815. 
E. EIDELBERG, C. F. BAXTER, E. ROBERTS AND C. A. SALDIAS, in E. Rosperts, Inhibition in 
the Nervous System and y-Aminobutyric Acid, Pergamon, New York, 1960, p. 3605. 
H. Batzer, P. Hottz anp D. Pam, Arch. exptl. Pathol. Phavmakol., Naunyn-Schmiedeberg’s, 
239 (1960) 520. 
10 H. Bavzer, P. Hoittz anv D. Pain, Experientia, 17 (1961) 38. 
11K. F. KitvaM AnD J. A. Bain, J. Pharmacol. Exptl. Therap., 119 (1957) 255- 
12 G. M.McKuann, R. W. ALBERS, L. SoKoLorF, O. MICKELSEN AND D.B.TowEeER, in E. 
Rosperts, Inhibition in the Nervous System and y-Aminobutyric Acid, Pergamon, New York, 
1960, p. 169. 
18 T. Tursky, Nature, 187 (1960) 322. 
14 G. RINDI AND G. FERRARI, Nature, 183 (1959) 608. 
15 TD. P. PurpuRA, S. BERL, O. GONZALEZ-MONTEAGUDO AND A. Wyatt, in E. RosBerts, Inhibition 
in the Nervous System and y-Aminobutyrvic Acid, Pergamon, New York, 1960, p. 331. 
16 GD. Gammon, R. Gumnit, R. P. KAMRIN AND A. KAmMRIN, in E. Rogperts, Inhibition im the 
Nervous System and y-Aminobutyric Acid, Pergamon, New York, 1960, p. 328. 
17S. Bert, D. P. Purpura, M. Girrapo anp H. Waetscu, J. Neurochem., 4 (1959) 311. 
18D. KesseL, Federation Proc., 18 (1959) 258. 
19 C. F. BAXTER, E. ROBERTS AND E. EIDELBERG, Federation Proc., 18 (1959) 187. 
20 C. F. Baxter, E. RoBERTS AND E. EIDELBERG, J. Neurochem., 5 (1960) 203. 
21 W. T. SULLIVAN AND L, M. Strone, Am. J. Physiol., 181 (1955) 43- 
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