VESTIBULAR INFLUENCES ON THE SYMPATHETIC NERVOUS SYSTEM

相当多的证据表明来自前庭系统的输入 对交感神经流出和血液产生直接和强大的影响 压力。电刺激前庭神经改变活动 从支配身体许多区域的交感神经记录下来的；这些 这种影响可能伴随着血压的变化。此外, 切断前庭神经会严重损害血压 猫对头朝上倾斜的补偿，表明前庭系统 参与纠正直立性低血压。的存在 作用于心血管系统的前庭交感神经反射不是 令人惊讶的是，因为姿势的变化可能会挑战 血压稳定，前庭系统提供的输入 当身体位置改变时发出信号，包括那些可能会影响 循环，正在发生。我们的长期目标是界定和研究 负责产生前庭交感神经反射的神经回路。 我们之前的工作表明，脑干两个区域的神经元， 延髓中缝尾侧核和延髓背侧核 延髓吻侧腹外侧，将前庭信号传递给交感神经 脊髓中的节前神经元。建议的实验是 旨在发现哪些脑干神经元参与了 这些脊椎投射细胞的迷路输入。通过利用 损伤技术和电生理方法，我们将确定： (1)哪些前庭核团介导前庭交感神经反射； 脑干中间神经元将前庭信号传递到脊髓- 投射血管运动神经元；以及(3)小脑是否影响 前庭引起的交感反应。因此，拟议的工作将 提高对未充分调查和未充分调查的 潜在的重要神经机制参与控制 发行量。

Considerable evidence suggests that inputs from the vestibular system have direct and powerful influences on sympathetic outflow, as well as blood pressure. Electrical stimulation of the vestibular nerve alters activity recorded from sympathetic nerves innervating many body regions; these effects can be accompanied by changes in blood pressure. In addition, transection of the vestibular nerves greatly impairs blood pressure compensation to head-up tilt in cats, suggesting that the vestibular system participates in correcting orthostatic hypotension. The existence of vestibulosympathetic reflexes which act on the cardiovascular system is not surprising, since changes in posture can challenge the maintenance of stable blood pressure, and the vestibular system provides inputs which signal when changes in body position, including those which can affect circulation, are occurring. Our long-term goal is to define and study the neural circuitry responsible for producing vestibulosympathetic reflexes. Our previous work has shown that neurons in two regions of the brainstem, the caudal medullary raphe nuclei and the subretrofacial portion of the rostral ventro-lateral medulla, transmit vestibular signals to sympathetic preganglionic neurons in the spinal cord. The proposed experiments are aimed at discovering which brainstem neurons participate in relaying labyrinthine inputs to these spinally-projecting cells. By making use of lesioning techniques and electrophysiological methods, we will determine: (1) which vestibular nuclei mediate vestibulosympathetic reflexes; (2) which brainstem interneurons relay vestibular signals to spinally- projecting vasomotor neurons; and (3) whether the cerebellum influences vestibular-elicited sympathetic responses. The proposed work will thus advance the basic scientific knowledge about an underinvestigated and potentially important neural mechanism involved in the control of circulation.