Harada Shotaro, Koyama Yoshihisa, Imai Takao, Takimoto Yasumitsu, Inohara Hidenori, Shimada Shoichi
Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan.
Biochem Biophys Rep. 2025 May 28;43:102066. doi: 10.1016/j.bbrep.2025.102066. eCollection 2025 Sep.
The vestibulo-ocular reflex (VOR) is an involuntary reflex essential for maintaining clear vision and balance during head movement. It stabilizes gaze by generating compensatory eye movements in the opposite direction to head movement, ensuring that the visual image is stable on the retina. Maintaining visual stability leads to enhanced postural control and balance, which are crucial for coordinating daily activities, such as exercise and driving. The two types of balance organs, semicircular canals and otolith organs, are involved in the VOR; however, how they interact to contribute to the VOR remains unclear. This study aimed to investigate the interrelationship between semicircular canals and otolith organs in terms of balance function by performing semicircular canal and otolith organ function tests using head-tilt (Het) mutant mice that lack otoconia. Linear VOR results indicated that eye movements induced by linear acceleration stimuli were not observed in Het mutant mice, regardless of the degree of gravitational acceleration. Angular VOR was observed in Het mutant mice at 1 and 2 Hz, but a reduced VOR gain was observed at 0.3 Hz. In wild-type mice, both the linear and angular VOR were normal. The present study demonstrated that in Het mutant mice, the angular VOR decreased after 0.3-Hz semicircular canal stimulation, but normal responses were observed after 1- and 2-Hz semicircular canal stimulation. These results suggest that otolith organs are closely involved in the angular VOR during slow rotational stimulation.
前庭眼反射（VOR）是一种非自主反射，对于在头部运动期间保持清晰视力和平衡至关重要。它通过产生与头部运动方向相反的代偿性眼球运动来稳定注视，确保视觉图像在视网膜上保持稳定。保持视觉稳定会增强姿势控制和平衡，这对于协调日常活动（如运动和驾驶）至关重要。两种平衡器官，即半规管和耳石器官，参与了VOR；然而，它们如何相互作用以促成VOR仍不清楚。本研究旨在通过使用缺乏耳石的头部倾斜（Het）突变小鼠进行半规管和耳石器官功能测试，来研究半规管和耳石器官在平衡功能方面的相互关系。线性VOR结果表明，无论重力加速度程度如何，在Het突变小鼠中均未观察到由线性加速度刺激诱发的眼球运动。在Het突变小鼠中观察到了1赫兹和2赫兹时的角VOR，但在0.3赫兹时观察到VOR增益降低。在野生型小鼠中，线性和角VOR均正常。本研究表明，在Het突变小鼠中，0.3赫兹半规管刺激后角VOR降低，但在1赫兹和2赫兹半规管刺激后观察到正常反应。这些结果表明，在缓慢旋转刺激期间，耳石器官密切参与角VOR。
