The vestibular system contributes to not only eye movement and posture but also the sympathetic response. Plastic alteration of the vestibulo-sympathetic reflex is induced by hypergravity load; however, the mechanism remains unknown. Here, we examined 2 g-induced changing in responsiveness of CAMK2-expressing neurons in the vestibular nucleus complex using optogenetic tools. The excitatory photostimulation of the CAMK2-expressing neurons in the unilateral vestibular nuclear complex induced body tilt to the contralateral side, while inhibitory photostimulation showed the opposite response. Photoactivation of either cell body or the axonal terminal in the rostral ventrolateral medulla showed sympathoexcitation followed by the pressor response. Furthermore, this response was significantly attenuated (49.8 ± 4%) after the 1st day of 2 g loading, and this value was further reduced by the 5th day (22.4 ± 3%), suggesting that 2 g-induced attenuation of the vestibulo-sympathetic reflex involves at least decrease in responsiveness of CAMK2-expressing neurons in the vestibular nuclear complex.

中文翻译：

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超重力引起的前庭交感神经反射的塑性改变涉及前庭核复合体中表达 CAMK2 的神经元的反应性降低。


前庭系统不仅有助于眼球运动和姿势，还有助于交感神经反应。前庭交感神经反射的塑性改变是由超重力负荷引起的；然而，其机制仍不清楚。在这里，我们使用光遗传学工具检查了 2 g 诱导的前庭核复合体中表达 CAMK2 的神经元的反应性变化。单侧前庭核复合体中表达 CAMK2 的神经元的兴奋性光刺激引起身体向对侧倾斜，而抑制性光刺激则表现出相反的反应。延髓头侧腹外侧的细胞体或轴突末端的光激活显示交感神经兴奋，随后是升压反应。此外，在 2 g 负载的第一天后，该反应显着减弱（49.8 ± 4%），并且该值在第 5 天进一步降低（22.4 ± 3%），表明 2 g 引起的前庭神经衰减交感反射至少涉及前庭核复合体中表达 CAMK2 的神经元的反应性降低。