Feedback and feedforward neural control of muscle glucose uptake during contraction

为了阐明肌肉交感神经(MS)神经系统(MSNS)作为神经控制的肌肉葡萄糖摄取(MGU)系统在收缩过程中传出通路的可能性，在麻醉大鼠坐骨神经上进行了显微神经成像技术的测试。在建立手术方法并明确MS纤维在神经束中的位置后，在仰卧位测量静息和诱发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，这是第一次使用显微神经图来测量小动物的MS神经活动(MSNA)。数据被存储在数据记录器中，并与个人计算机系统脱机分析。建立了MSNA的识别标准，用包括积分神经图在内的常规方法对MSNA进行了评价，并提出了一种新的基于连续小波变换的动作电位检测方法。结果表明，在肌肉收缩过程中，BG下降并伴有MSNA的增强，提示MSNS是MGU神经反馈控制系统中的传出通路。为了接近中心前馈控制系统，将大鼠头固定在立体定向框架中，建立了俯卧位MSNA的显微神经学记录方法。下丘脑腹内侧核(VMH)是中枢神经系统控制中枢的候选核团之一，人们认为VMH在静息状态下会影响MGU，因此用钨微电极研究VMH中的神经信号。然而，还没有很好地确定VMH的位置或来自VMH的信号，因此认为有必要开发新的方法，例如FOS方法，以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.