370 K. LISSAK, E. ENDROCZI AND E. VINCZE 



In the present lecture I wish to present a picture of our resuhs obtained 

 last year with an extract from brain tissue and y-aminobutyric acid, and with 

 the biological effects of y-amino-;8-hydroxybutyric acid. The extract was 

 prepared partly from dog's brain and partly from ox brain with the method 

 used by us in earlier experiments. One volume of 96% cthanol having been 

 added to it, the freshly removed tissue was homogenized and then, after the 

 addition of one more volume of ethanol and one volume of colloidal aluminium 

 hydroxide, centrifuged. The transparent supernatant, slightly yellow in colour, 

 was concentrated in vacuo to one-tenth of its original volume, clarified with 

 active carbon, concentrated, then filtered, and the filtrate evaporated in vacuo. 

 The residue was redissolved in from 10 to 50 ml aqueous ethanol (1:1 v/v) 

 and after the repeated addition of active carbon fihered and again evaporated 

 in vacuo. Depending on the initial amount of the substance, the residue was 

 dissolved in from 1 to 10 ml 50% ethanol, and then run on Whatman No. 4 

 paper partly with a mixture of phenol-water and partly with one of butanol- 

 glacial acetic acid-water (4 : 1 : 1 by volume). In the case of descending 

 chromatography, different amounts of GAB A and GABOB were run for 

 testing and demonstrated with the ninhydrin reaction. After the ninhydrin 

 reaction, and then dissolution in ethanol: 0-1 n NaOH (4 : 1 v/v), estimation 

 of the GABA content in the brain tissue was done photometrically with 

 standard GABA. It should be mentioned here that a series of qualitative 

 chemical reactions were carried out on the paper chromatograms of the brain 

 tissue. Of these the formation of picrate obtained in alkaline miheu deserves 

 to be mentioned. As can be seen in Fig. 1, the picrate-positive area in the 

 system butanol-acetic acid-water shows a position similar to that of GABA. 

 I wish to mention here that in a different chromatographic system, thus in 

 one of phenol-water too, the ninhydrin positive GABA was situated 

 similarly to the picrate positive substances in the brain tissue. The importance 

 to be ascribed to this observation cannot be decided as yet. However, it was 

 the same area that, in the course of biological testing, proved active with 

 regard to inhibition. 



I shall now pass on to the description of results suggesting that the brain 

 extract contains an inhibitory factor, but GABA or GABOB can only partly 

 be responsible for the inhibitory effect. 



(a) According to observations on isolated cat ileum, the extract eluated 

 from the paper chromatogram is able to inhibit acetylcholine contraction at 

 or below pH 7, while, at the same time, in the case of GABA or GABOB 

 even several hundred micrograms are ineffective. The GABA content in the 

 brain extract that proved effective hardly exceeded 10-15 ^g, which shows 

 that GABA or its derivative cannot be responsible for the inhibition. 



(b) When examining on the motor cortex of the cat the electrical threshold 

 stimulus for the motor reaction of a foreleg, we found that while local 

 application of an amount of brain extract obtained from one-tliird of a dog's 



