Feedback and feedforward neural control of muscle glucose uptake during contraction

为了阐明肌肉交感神经系统（MS）作为收缩过程中神经控制肌肉葡萄糖摄取（MGU）系统的传出通路的可能性，在麻醉大鼠坐骨神经中进行了微神经图技术测试。在确定手术方法并明确MS纤维在神经束中的位置后，在仰卧位下，测量静息时和诱导肌肉收缩时同侧后肢的多纤维MSNA和血糖水平（BG）。据我们所知，这是微神经造影首次用于小动物多发性硬化症神经活动（MSNA）的测量。数据被存储在数据记录仪中，并通过个人计算机系统离线分析。在此基础上，提出了一种新的动作电位检测方法，并利用综合神经图等传统方法对动作电位进行了评价。结果显示BG在肌肉收缩过程中降低，同时伴有MSNA的增强，提示MSNA是MGU神经反馈控制系统的传出通路。为了研究中央前馈控制系统，将大鼠头部固定在立体定向框架中，并建立了用微神经摄影记录俯卧位MSNA的方法。下丘脑腹内侧核（VMH）作为中枢神经系统的候选控制中枢，由于VMH被认为会影响下丘脑腹内侧核（VMH）在静止状态下的神经信号，因此试图用钨微电极来寻找VMH的神经信号。然而，目前还没有很好地确定VMH的位置或信号，因此有必要开发新的方法，例如Fos方法，以便在未来的项目中识别它们。

To clarify a possibility of muscle sympathetic (MS) nervous system (MSNS) as an efferent path of neurally controlled muscle glucose uptake (MGU) system during contraction, microneurographic technique has been tested in the sciatic nerve of anesthetized rats. After surgical methodology has been established and the location of MS fibers in the nerve bundle has been clarified, in the supine position, multi-fiber MSNA and blood glucose level (BG) were measured at rest as well as during induced muscle contraction in the ipsilateral hindlimb. To our best knowledge, this was the first case that the microneurography was used for the measurement of MS nerve activity (MSNA) in small animals. The data was stored in a data recorder, and analyzed off-line with a personal computer system. A criteria to identify MSNA have been established, MSNA was evaluated with conventional methods including the integrated neurogram, and a novel method using continuous wavelet transform has been developed for detecting action potentials. Results showed that the BG decreased during muscle contraction and that it was accompanied with an enhancement of MSNA, suggesting the MSNS is the efferent path in the neural feedback control system of MGU.To approach the central feedforward control system, rat heads were fixed in a stereotactic frame, and methodology has been established to record MSNA in the prone position by microneurography. As a candidate of the control center in the central nervous system, neural signal in the ventromedial hypothalamus nuclei (VMH) has been tried to find out with a tungsten microelectrode, because VMH is believed to affect MGU at rest. However, it has not been established well yet to identify the location of or signal from VMH, It is considered to be necessary to develop new methods, including Fos method for example, to identify them in the future projects.