家兎小脳の呼吸運動に対する影響

ON THE EFFECT OF CEREBELLAR STIMULATION UPON THE RESPIRATORY MOVEMENT IN RABBIT

I．はじめに

　小脳刺激による自律系の変化は古くから報告されていたが，それらは実験操作の不備によるとされていた。しかしMoruzzi^1）（1940）は頸動脈洞反射の結果現われた呼吸増強が前葉刺激で抑制されることをみいだし，須田ら^2）（1944）および内山^3）（1956）は小脳皮質のグルタミン酸ソーダ溶液やクエン酸ソーダ溶液その他による刺激で，そしてCross^4）（1959）は小脳核の電気的刺激で呼吸運動の変化を観察した。しかしその変化を認めなかつた報告^5）6）もあり，まだ小脳と呼吸運動の関係は十分に解明されているとはいえない。それで家兎の呼吸運動におよぼす小脳各部皮質のクエン酸ソーダによる化学的および種々の電気的刺激の影響を観察し，二，三の知見を得たので報告する。

The effect of chemical (2mo1 citraste sodium) and electrical stimulation (1-25V, 0.1-4 m sec, 5-200 /sec) to the cerebellar cortex on the respiratory movement were observed in 43 rabbits. Injection of 0.02 ml citrate sodium solution into the cerebellar cortex of the anterior lobe, tuber vermis, pyramis, uvula vermis and flocculus produced changes in the respiratory movements, whereas changes due to the electrical stimulation were induced not only in these regions but also in the ansiform lobulus. Moreover, the effects were most pronounced with stimulation to the anterior portion of the anterior lobe and uvula vermis.

Chemical stimulation to the uvula vermis elicited an increase in the respiratory amplitude preceded by a diminution of the amplitude, whereas this di-minution was not exhibited by the stimulation to the anterior portion of the anterior lobe in most instances.

Electrical stimulation to the anterior and posterior portions of the anterior lobe brought out an increase of respiratory amplitude in the former and an aug-mentation of both the amplitude and frequency in the latter respectively. The same stimulation to the tuber vermis, pyramis, uvula vermis and ansiform lobulus produced an increase in respiratory fre-quency and a slight decrease in the amplitude. In ad-dition, stimulation to the paramedian lobulus caused augmentation of either the respiratory frequency or amplitude.

The threshold of respiratory changes was observed to vary with increasing the frequency and duration of the electrical stimulation, whereas the effect be-came more distinct with increasing the stimulating intensity and, in some instances, different changes were also induced.

Though some differences in the relationship bet-ween the frequency of cerebellar. electric stimula-tion and the threshold for respiratory changes were noted before and after decerebration by intracolli-cular trasection, there were no differences in the other changes. This latter finding suggests that the effect of the cerebellum upom the activity of the respiratory center is independant of the upper brain, whereas the former finding suggests that the influence of the cerebellum upon the respiratory center is cor-related to that of the upper brain.