末梢神経電気刺激誘発筋電図法による脊髄機能の研究

Studies on the Spinal Function by Means of Evoked EMG Method Stimulating the Peripheral Nerve

緒言

　最近Magladery等^1）はHoffmanの実験^2）を更に展開し，人間を対象として経皮的に主としてN.-tibialisに電気刺激を加えて，M.gastrocne-miusの誘発筋電図を観察し，その場合運動線維の興奮が刺激部位から直接筋に達して起す誘発筋電図である直達性の所謂M波と，筋紡錘起源のUoydの所謂Group 1 fibre^3）の興奮が脊髄を迂回して筋に達して起す，潜時の長い反射性の所謂H波とを識別し，主としてこのH波を対象として一連の基礎実験を行うと共に^4）〜9），脳脊髄性運動障害患者の場合，H波の現れ方の時間的経過に変化の現われることを指摘している^{10）〜13）}。

　我が国においても，本間（伊）^14）は藤森教授の指導のもとに，下肢の運動障害をもつ脊髄梅毒，脊髄腫瘍患者等について，N. tibialis刺激によるM.-gastrocnemiusのH波を検査したところその形態に変化が見られたと報告している。

Forty-five decorticated cats were used in_ these experiments. Monopolar cathodal shoks of 1 msec., duration were applied through the intact skin to posterior tibial nerve be-hind the knee, dependent on the nature of the experiment.

Muscle action potentials were led to ampli-fiers and two beams cathod ray ociloscope through paired surface electrodes fixed to the skin overlying the gastrocnemius muscles.

The excitation of spinal ventral cells were changed by various drugs, using the H wave.

1. In cats anesthetized by ether, chloro-form, urethan, or chloral hydrate, when the knee jerk reflex was depressed a little, the threshold of H wave increased, and finally disappeared.

2. Cats to which small doses of barbitu-rates were given (thiopental sodium, pheno-baribital or hexobarbital sodium) showed that, when knee jerk reflex was excited a little, the threshold of H wave decreased.As larger doses were given H threshold was increased or disappeard, and the knee jerk reflexes were depressed too.

3. When strychnine was given cats the knee jerk reflex was excited, and the thre-shold of H wave decreased.