麻酔剤並びに賦活剤の脳蛋白質代謝に及ぼす影響

The Effects of Anaesthetics and of Activators on the Protein Metabolism of the Brain

I．緒論

　脳の生化学は，多くの点で未だ未開拓の分野であり，同時に最も興味ある種々の問題を提示しているが，一方脳組織では多種多様な細胞及び線維構造がみられ，灰白質と白質の分布も非常にこみ入つて居り，それらは部位による化学的組成の変化と，更に不安定燐酸化合物の変動と相俟つて，脳の物質代謝の研究を最も困難な方向に導いている。

　しかし最近では放射性同位元素が，研究分野に盛んに利用されるようになり，脳の機能生化学にも新しい方法が導入され，脳髄の主要な生理的状態，即ち興奮と制止の状態に伴う物質代謝の研究に，一大進歩をもたらした事は今更述べる迄もないが，近時，特に意識障害に関する生化学的解明の一環として，各種麻酔剤による脳物質代謝の影響に就いても，この放射性同位元素を用いる方法が盛んに利用され，各方面から活溌な研究が為されている。

The guinea pig brain slices were incubated with 2-C¹⁴-glycine in the Krebs-Ringer phosphate or in the modified Mc Ilwain's medium, containing glucose as substrate, and the effect of various drugs on the rate of the incorporation of C¹⁴-glycine into the brian proteins was observed.

The results were as follows :

1. When thiopental or chlorpromazine was added into the medium, oxygen uptake of the brain slices was reduced, and the incorporation of .04-glycine into the brain proteins was also inhibited significantly.

2. The creatine phosphate content of the brain slices after the incubation with thiopental or chlorpromazine also decreased remarkably.

3. The addition of low concentrations of 2.4-dinitrophenol into the medium brought about an increase of the oxygen consumption. But the incorporation of C¹⁴-glycine into the brain pro-tein was inhibited strikingly.

4. When megimide was added into the medium, oxygen consumption of the brain slices as well as incorporation of C¹⁴-glycine into the brain proteins was enhanced and the creatine phos-phate content of the brain slices also increased largely.

5. The above results with the brain slices were compared with those with the liver slices, and it was noted that the brain slices were more sensitive to the narcotics and activators than the liver slices.

The specific activities of the proteins and of acid soluble fractions of the rabbit brain and liver tissues were determined at 2 hours after the intracisternal and intraperitoneal injection of 2-C¹⁴-glycine.

The results were as follows :

1. A group of five rabbits anaesthetized by intra-peritoneal injection of 60mg/kg thiopental sho-wed relatively low specific activities in the brain and liver protein fractions.

2. Similar results were shown in a group of five rabbits to which 30mg/kg of chlorpromazine was injected intraperitoneally.

3. A group of five rabbits to which 30mg/kg of megimide was injected intraperitoneally, did not show any significant change in the specific activities of the brain and liver protein frac-tions.