BILABYRINTHECTOMY EFFECTS ON MUSCLE FIBER TYPES

前庭系统包括运动和感觉两部分。 虽然中枢神经系统的连接涉及前庭 系统进行了初步的设计，系统的电机控制效果良好， 不太清楚，大多数结论都基于运动行为。 显然 肢体伸肌和眼外肌的表现， 通过前庭输入促进;然而，没有研究 已完成，证明是否稳定输入的 前庭系统影响肌纤维类型的发育， 纤维直径或区室化在任何一组肌肉。 此外，病变中出现的异常运动行为的原因 对前庭成分的研究还不是很清楚。通过检查 在存在外周前庭损失的情况下肌纤维改变， 这项研究将有助于了解正常和 病态运动 我们假设双侧睾丸切除术 将改变肌纤维类型分布和生物力学一致性 在反重力肌肉中，这是由于失去了来自两个躯干的输入。 所涉及的纤维将是最不容易疲劳的，间隔化的， 离骨头最近 前庭对运动发育的贡献将在一个 雪貂模型 新生的雪貂将接受双侧睾丸切除术 破坏前庭感受器 组织学和 这些雪貂肌肉的肌球蛋白生化含量 与未改变的对照动物相比。 结果将证明 外周前庭成分对肌纤维的影响， 隔室发育 在本提案的最后一年，我们 将继续调查一个关键时期的可能性， 前庭的影响，并在未来，检查收缩 肢体和眼外肌的特征。 最终目标 是为了更好地了解外周前庭输入的作用 运动的发展，并有助于了解运动 行为在存在双侧外周前庭病变。

The vestibular system comprises both motor and sensory components. While central nervous system connections involved in the vestibular system have been lelineated, the system's effect of motor control is less clear, basing most conclusions on motor behavior. It is clear that limb extensor and extraocular musculature performances are facilitated by vestibular input; however, no studies have been completed which demonstrate whether or not the steady input of the vestibular system influences the development of muscle fiber types, fiber diameter or compartmentalization in either group of muscles. Additionally, the cause of abnormal motor behavior seen in lesion studies of vestibular components is not well-understood. By examining muscle fiber changes in the presence of peripheral vestibular loss, this study will contribute to the understanding of normal and pathological movement. We hypothesize that bilateral labyrinthectomy will alter muscle fiber type distribution and biomechanical consistency in anti-gravity muscles secondary to lost input from both labyrinths. The fibers involved will be the least fatigable, compartmentalized, and lie closest to the bone. The vestibular contribution to motor development will be studied in a ferret model. Neonatal ferrets will undergo bilateral labyrinthectomy to destroy the vestibular sensory receptors. The histology and biochemical myosin content of muscle from these ferrets will be compared with unaltered control animals. The results will demonstrate the effect of peripheral vestibular components on muscle fiber and compartment development. During the final year of this proposal, we will go on the investigate the possibility of a critical period of vestibular effects, and, in the future, examine the contractile characteristics of the limb and extraocular muscles. The ultimate goal is to better understand the role of the peripheral vestibular input on motor development and contribute to the understanding of motor behavior in the presence of bilateral peripheral vestibular lesions.