Feedback and feedforward neural control of muscle glucose uptake during contraction

为阐明肌肉交感神经系统（MS）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摄影技术的实验。在建立手术方法并明确神经束中MS纤维的位置后，在仰卧位，在休息时以及在同侧后肢诱导肌肉收缩期间测量多纤维MSNA和血糖水平（BG）。据我们所知，这是第一例显微神经造影术用于小动物MS神经活动（MSNA）的测量。将数据存储在数据记录器中，并用个人计算机系统进行离线分析。建立了鉴别MSNA的标准，用包括综合神经图在内的常规方法对MSNA进行了评价，并发展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，肌肉收缩时BG降低，MSNA增强，提示MSNS是MGU神经反馈控制系统的传出通路。为了探讨中枢前馈控制系统，将大鼠头部固定在立体定向架上，建立了俯卧位MSNA的显微神经成像方法。下丘脑腹内侧核（VMH）是中枢神经系统的一个潜在控制中心，它在静息状态下对肌球蛋白产生影响，因此，人们试图用钨微电极研究VMH的神经信号。然而，它还没有建立很好的识别VMH的位置或信号，它被认为是必要的开发新的方法，包括Fos方法，例如，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.