てんかん脳の生化学的研究

Biochemical Studies on Cerebral Cortex of Idiopathic Epileptic Patients

　真正てんかんの成因に関してはかなり以前から種々の説が提唱されており，そのうち従来注目せられてきたもののみを挙げても，酸塩基平衡障害，血液の酸素炭酸ガス平衡障害，水分代謝障害，脳の含水状態の異常，塩分代謝障害，血糖異常，血管攣縮説，脳および脳脊髄液内の痙攣毒説，内分泌障害説，acetylcholine代謝障害，glutamin酸代謝障害など枚挙に遑がない。しがし，これらの報告をみると，人脳を直接使用して研究を行つたものはきわめて少く，多くのものは患者の血液とか脳脊髄液の分析の成績から推察を行つたものである。

　さて，最近こなつて脳外科の進歩にともない，治療の目的で真正てんかん脳の剔除が行われるようになるにおよび，その際えられる脳組織片をもちいて，てんかん脳の生化学的特長を解明しようとする試みが行われるにいたつたが，私どもの教室においても1952年頃から真正てんかん脳の生化学的研究を開始し，現在までにいくつかの新しい知見をえてきた。今，ここにそれらの概要を述べて諸賢の御批判を仰ぎたいと考える。

Biochemical studies on the cerebral cortex ofepileptic patients, on whom corticoectomy wasperformed in this department, were reported asfollows.

1. Acetylcholine metabolism.

The cerebral cortex of idiopathic epileptic pa-tients has a accerelated cholinestrase activity, butit was recovered from this abnormality to normallebel when amino acid (γ-aminobutyric acid (GABA), glutamic acid, glutamine, and aspargine)was added into the experimental, system.

2. glucose metabolism

In the idiopathics, the brain homogenate usedless amount of glucose than of the non-epileptics,and the hexokinase activity and the oxidation ac-tivity of members of TCA cycle and intermediatesin Warburg-Dickens pathway by brain mitochond-ria or homogenate, were decreased as comparedwith the none-epileptics.

The defect in glucose using of the epilepticbrain homogenante was recovered also by addingof glutamic acid, glutamine, aspartic acid, aspargineand GABA.

3. Amino acid metabolism

In the epileptics, free amino acids content of thecerebral cortex were decreased makedly, and theseamino acids involed glutamic acid and GABA.

As to the activities of aspartic-glutamic and 7-aminobutyric-glutamic transaminases, no differentin activities were found between the idiopathicepileptics and non-epileptics.

Conversion of ¹⁴C-glucose into free amino acidsof the brain, in idiopathic epileptics, were thanthat of the non-epileptics, above all into asparticacid and GABA.

4. GABOB

The content of γ-amino-β-hydroxybutyrie acid(GABOB) in the cerebral cortex, known as centralinhibitory substance and intermediate of GABA,was decreased in epileptics as compared with non-epileptics, it is very interesting phenomenon, be-cause GABOB is physiological inhibitory substanceof central nervous system.

The oxidation of GABOB by the brain homo-genate was measured on the other hand, and itwas found that oxidation of GABOB was relati-vely accerelated in the idiopathic epileptics ascompared with the others.