Ontogeny of Mouse Vestibulo-Ocular Reflex Following Genetic or Environmental Alteration of Gravity Sensing
Ontogeny of Mouse Vestibulo-Ocular Reflex Following Genetic or Environmental Alteration of Gravity Sensing
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DOI：
10.1371/journal.pone.0040414
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发表时间：
2012-07-10
期刊：
影响因子：
3.7
通讯作者：
Vidal, Pierre-Paul
中科院分区：
文献类型：
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作者：
Beraneck, Mathieu;Bojados, Mickael;Vidal, Pierre-Paul
前庭器官由互补的传感器组成：半规管检测旋转，而耳石检测线性加速度，包括重力的恒定拉力。关于前庭系统如何发展和/或适应长期重力变化，例如在长期太空旅行期间，仍然存在几个基本问题。如果耳石和半规管的适当组装受到干扰，前庭反射如何发展？本工作的目的是评估前庭系统的个体发育过程中的重力感应的作用。在耳锥缺陷小鼠（ied）中，重力不能被感觉到，因此斑眼反射（莫尔）不存在。当存在与小管相关的反射时，IED缺陷也导致与水平角小管相关的VOR的异常空间调谐。为了确定假定的耳石相关的关键时期，正常C57 Bl/6 J小鼠在不同的发育期或成年期（成年-HG）通过慢性离心经受2G超重力，并与未离心（对照）C57 Bl/6 J小鼠进行比较。在发育期间暴露于超重力的小鼠在离心结束后6个月具有完全正常的前庭眼反射。成年HG小鼠在恢复正常重力后一个月均显示出黄斑眼反射的主要异常。在接下来的5个月里，有一半的人适应了正常的重力。总之，重力感应的遗传抑制表明，耳石相关的信号可能是必要的，以确保正常运作的运河相关的前庭反射。另一方面，在发育过程中暴露于超重力不足以持久改变运动行为。因此，在发育过程中，2G离心显示没有耳石特定的关键期。
The vestibular organs consist of complementary sensors: the semicircular canals detect rotations while the otoliths detect linear accelerations, including the constant pull of gravity. Several fundamental questions remain on how the vestibular system would develop and/or adapt to prolonged changes in gravity such as during long-term space journey. How do vestibular reflexes develop if the appropriate assembly of otoliths and semi-circular canals is perturbed? The aim of present work was to evaluate the role of gravity sensing during ontogeny of the vestibular system. In otoconia-deficient mice (ied), gravity cannot be sensed and therefore maculo-ocular reflexes (MOR) were absent. While canals-related reflexes were present, the ied deficit also led to the abnormal spatial tuning of the horizontal angular canal-related VOR. To identify putative otolith-related critical periods, normal C57Bl/6J mice were subjected to 2G hypergravity by chronic centrifugation during different periods of development or adulthood (Adult-HG) and compared to non-centrifuged (control) C57Bl/6J mice. Mice exposed to hypergravity during development had completely normal vestibulo-ocular reflexes 6 months after end of centrifugation. Adult-HG mice all displayed major abnormalities in maculo-ocular reflexe one month after return to normal gravity. During the next 5 months, adaptation to normal gravity occurred in half of the individuals. In summary, genetic suppression of gravity sensing indicated that otolith-related signals might be necessary to ensure proper functioning of canal-related vestibular reflexes. On the other hand, exposure to hypergravity during development was not sufficient to modify durably motor behaviour. Hence, 2G centrifugation during development revealed no otolith-specific critical period.