ネコ扁桃核内キスカリン酸微量注入により誘発される辺縁系部分発作の特徴

EPIL EPTOGENIC PROPERTIES OF QUISQUALIC ACID:MICROINJECTION INTO THE UNILATERAL AMYGDALA IN CATS

　抄録　カイニン酸（KA）と並ぶ興奮性アミノ酸であるキスカリン酸（QA）の，てんかん惹起効果を，慢性深部電極を植え込んだネコの扁桃核内にQAを微量注入し検討した。QA 2μgの注入では脳波および行動上に変化は見られなかったが，5μgで，辺縁系に限局する，てんかん性発作波の誘発を認め，行動上わずかの注意反応ないし軽症の辺縁系発作の特徴を認めた。15μgの注入では，辺縁系部分発作の重積状態が誘発され，多くの例ではその回復後に辺縁系に限局する発作間発射が長期間観察された。その一部の例に辺縁系発作重積状態からの回復後，自発性の二次性全般化痙攣発作が起こるようになった。病理組織学的所見では，15μg注入群において，両側海馬のCA 3およびCA 4のpyramidal cell layerに変性が認められた。QAのてんかん発作惹起効果は，KAのそれに比較し弱く，かつ脳波上特徴的な発作波を呈する。以上の特徴は，ヒトのcomplex partial seizureに見られる所見によく類似しており，その実験てんかんモデルに値すると思われる。

The present studies demonstrated that the microinjection of quisqualic acid (QA) into uni-lateral amygdala in chronically implanted cats re-sulted in various types of limbic seizures in ac-cordance with injected doses.

The epileptogenic potency of QA in the in-duction of epileptic seizures was lower then that of kainic acid (KA), which has also been demon-strated in our previous studies.

Electroencephalographic changes and clinical manifestations of QA-induced epilepsy were less prominent as compared with those of KA-induced epilepsy. Five micrograms of QA resulted in pure amygdaloid seizures. The moderate dose admini-stration of QA (15 pg) was suitable to observe limbic status. Both doses of QA elicited similar characteristic epileptic patterns on EEG, which was quite distinguishable from those of KA.

In pathological study, mild degeneration of hip-pocampal pyramidal cell layer was observed in the cases injected 15 pg of QA. These electro-clinical and pathological features are interesting in similar-ities to those of human complex partial seizures, mesial temporal sclerosis.

In conclusion, the strict dose dependency of QA in the production of limbic seizures is a valid advantage for an experimental model of a complex partial epilepsy in man.