DRUGS AND FREE AMINO ACIDS IN BRAIN 489 
TABLE IV 
FREE AMINO ACIDS PRESENT IN RAT BRAIN 
AT CONCENTRATIONS OF <6.0 mg/Ioo g 

Cysteic acid 
Glycerophosphoethanolamine 
Phosphoethanolamine 
Methionine 
Leucine 
Isoleucine 

(a) These drugs are known to be capable of increasing (MAO inhibitors)® or re- 
leasing (reserpine)? a number of amines in brain. This alteration of the amines may 
also induce a change in the amino acid composition. 
(b) MAO inhibitors and reserpine respectively are active in preventing! or en- 
hancing convulsions!!. On the other hand, some types of convulsion seem to be related 
to changes of glutamic acid, glutamine and GABA?! 8, 
The effect of electroshock was also investigated in connection with these data. 
CONHNHCH (CH,), CH,CH,NHNH, 
| 
I (Ax ( iat 
\ n/ NVA 
Iproniazid Phenelzine (W 1544) 
CH 
| ; /Cs 
CH,—CH—NHNH, CH—CH,—NH, 
Ill | | IV 
VS Via 
WA oy, 
1/183 Gans) Tranyleypromine SKF 385 
MAO inhibitors were given intraperitoneally for 6 days at the doses reported in 
the tables. Table V shows that the conditions chosen were adequate for inducing a 
change of the brain amines in the expected way. MAO inhibitors such as reserpine, 
do not alter the concentration of the total amino acids before or after hydrolysis 
(see Table VI). The spectrum of amino acids in brain after MAO-inhibitor treat- 
ments is reported in Table VII. Although a certain MAO inhibitor may alter a given 
amino acid, a common pattern of effects was not observed. The hydrazine type of 
inhibitors, but not phenylcyclopropylamine, reduce the peak of free taurine. Con- 
jugated aspartic acid was increased by all treatments although only phenelzine 
reduced the free aspartic acid. Threonine was usually reduced as was serine in the 
case of phenelzine treatment. Glutamic acid was not affected but the conjugated 
References p. 492 
