無重力下における温度性眼振発現機序 4:クプラ両側内リンパ圧差と眼振の関係

Abstract

The endolymphatic pressure in the semicircular canal has been considered as the mechanism of caloric nystagmus. The endolymphatic pressure difference between both sides of cupula with caloric stimulation in the external ear canal was +0.2 mm H2O. The threshold of the endolymphatic pressure difference between both sides of cupula for nystagmus was tried to measure but at the maximum endolymphatic pressure difference between both sides of cupula resulted with stimulation in the semicircular canal membranous labyrinth, nystagmus was not observed. Therefore, the mechanism of caloric nystagmus on the earth is not explained by 'semicircular canal endolymphatic pressure changing theory', but the mechanism of caloric nystagmus in the space will be investigated.

無重力下での温度性眼振発現機序として、半規管内リンパ圧に注目している。ハトの水平半規管で外耳道に対する冷温刺激で生じるクプラ両側内リンパ圧差の閾値を求めようとしたが、半規管膜迷路圧迫刺激により生じた最も大きなクプラ両側内リンパ圧差（急性変化:+50mmH2O, 持続的変化:+4mmH2O) では、眼振は生じなかった。従って温度性眼振発現に「半規管内リンパ変化説」はほとんど寄与していないと言えるが、宇宙での温度性眼振発現については今後の検討が待たれる。