Department of Biological Science, Florida State University, Tallahassee, Florida, United States.
Department of Psychology, Florida State University, Tallahassee, Florida, United States.
Am J Physiol Regul Integr Comp Physiol. 2023 Aug 1;325(2):R181-R192. doi: 10.1152/ajpregu.00317.2022. Epub 2023 Jun 12.
Static high magnetic fields (MFs) interact with the vestibular system of humans and rodents. In rats and mice, exposure to MFs causes perturbations such as head movements, circular locomotion, suppressed rearing, nystagmus, and conditioned taste aversion acquisition. To test the role of otoconia, two mutant mouse models were examined, Nox3 () and Otop1 (), with mutations, respectively, in Nox3, encoding the NADPH oxidase 3 enzyme, and Otop1, encoding the otopetrin 1 proton channel, which are normally expressed in the otolith organs, and are critical for otoconia formation. Consequently, both mutants show a near complete loss of otoconia in the utricle and saccule, and are nonresponsive to linear acceleration. Mice were exposed to a 14.1 Tesla MF for 30 min. After exposure, locomotor activity, conditioned taste aversion and c-Fos (in ) were assessed. Wild-type mice exposed to the MF showed suppressed rearing, increased latency to rear, locomotor circling, and c-Fos in brainstem nuclei related to vestibular processing (prepositus, spinal vestibular, and supragenual nuclei). Mutant mice showed no response to the magnet and were similar to sham animals in all assays. Unlike mutants exposed to the MF showed significant locomotor circling and suppressed rearing compared with sham controls, although they failed to acquire a taste aversion. The residual responsiveness of versus mice might reflect a greater semicircular deficit in mice. These results demonstrate the necessity of the otoconia for the full effect of exposure to high MFs, but also suggest a semicircular contribution.
静磁场（MFs）与人类和啮齿动物的前庭系统相互作用。在大鼠和小鼠中，暴露于 MF 会引起头部运动、圆形运动、抑制后肢站立、眼球震颤和条件性味觉厌恶获得等扰动。为了测试耳石的作用，研究了两种突变小鼠模型，Nox3（）和 Otop1（），分别在编码 NADPH 氧化酶 3 酶的 Nox3 和编码耳石蛋白 1 质子通道的 Otop1 中发生突变，这两种蛋白通常在耳石器官中表达，对耳石形成至关重要。因此，两种突变体在耳石和囊均表现出几乎完全缺失耳石，并且对线性加速度无反应。将小鼠暴露于 14.1 特斯拉 MF 中 30 分钟。暴露后，评估运动活动、条件性味觉厌恶和 c-Fos（在）。暴露于 MF 的野生型小鼠表现出抑制后肢站立、后肢站立潜伏期增加、运动旋转和与前庭处理相关的脑干核（前位、脊髓前庭和上颈核）中的 c-Fos。突变体 小鼠对磁铁无反应，在所有检测中均与假动物相似。与假对照相比，与假对照相比，暴露于 MF 的突变体 小鼠表现出明显的运动旋转和抑制后肢站立，但未能获得味觉厌恶。与 突变体相比， 突变体的残余反应性可能反映了 小鼠的半规管缺陷更大。这些结果表明耳石对于暴露于高 MF 的全部影响是必要的，但也表明半规管有一定的贡献。
