電撃重積脳組織のアンモニア処理機構に関する研究

STUDIES ON THE AMMONIA-BINDING MECHANISM IN THE BRAIN TISSUE INFLUENCED BY THE REPEATED ELECTRICALLY INDUCED CONVULSIONS

　電撃重積動物の脳代謝，とくにアンモニア処理機構を追求する目的で本実験を行い，併せて基質代謝に及ぼす電撃重積の影響を検索した。

　成熟モルモツトに，頭部通電による電撃重積を施し，重積回数50回以下（電撃重積I群）50回以上（同II群）に大別した。

　正常対照群，電撃重積I，II群のモルモツトの大脳皮質切片を，基質を含まないKrobs-Ringer液，ブドウ糖，焦性ブドウ酸，グルタミン酸，α-ケトグルタール酸を基質に含むmediumに夫々浮遊させ，アンモニア形成量，酸素消費量を測定して得た成績は次の如くである。

　1）正常対照群では，グルタミン酸を基質に用いた場合が最も酸素消費量が大ぎく，焦性ブドウ酸，α-ケトグルタール酸，ブドウ糖がこれに次ぐ。

　アンモニア形成量は，基質なしの場合が最も生成が大きく，α-ケトグルタール酸は初めアンモニア形成を抑制するが，後その能力を失い，ブドウ糖，焦性ブドウ酸，グルタミン酸は強くアンモニア形成を抑制する。

　2）電撃重積群では，各mediumともに酸素消費量に関しては，正常対照群との間に差異を認めない。

These experiments were made for the pur-pose of studying the ammonia binding mec-hanism in the brain tissue of a guinea pig the functions of which were disturbed by me-ans of the repeated electric convulsions.

The electrical convulsions were applied on two groups of adult guinea pigs; 1st group on which the electrical convulsions were re-peated less than 50 times, while 2nd group more than 50 times.

The results obtained by measuring the am-monia formation and the oxygen uptake of the respective brain slices suspended in Kre-bs Ringer phosphate saline which contained glucose, pyruvate, glutamate or α-ketogluta-rate as substrate, were as follows.

1) The oxygen uptake by the normal gui-nea pig brain slices is the greatest in the presence of glutamate as substrate, and as to the other substrates the order of the gre-atness is: pyruvate, α-ketoglutarate, glucose.

The ammonia formation by that is the greatest in the absence of substrate. Ammonia formation in the presence of α-ketoglutarate, suppressed at the beginning of incubation,is observed in a short time.

When glucose, pyruvate or glutamate are added as substrate, ammonia formation is clearly suppressed.