Zochodne D W, Ho L T
Department of Medicine, Queen's University, Kingston, Ont., Canada.
Brain Res. 1991 Apr 12;546(1):113-8. doi: 10.1016/0006-8993(91)91165-w.
We studied the influence of graded nerve trunk stimulation on endoneurial blood flow (NBF), oxygen tension and pH in the rat sciatic nerve. The purpose of the investigation was to explore changes in the in vivo microenvironment of axons which result from their metabolic activation. Using endoneurial microelectrodes, we made serial measurements before, during and after varying stimulation protocols in curarized animals. NBF was increased by stimulation and the effect was directly related to the frequency, length and intensity of the stimulation train. At an intensity designed to supramaximally recruit myelinated fibers, high frequency (50 and 100 Hz) and prolonged duration (5-15 min) stimulation increased NBF. The effect was partly blocked by infiltration of lidocaine at the stimulating site. High intensity stimulation, designed to also recruit unmyelinated fibers, was particularly effective in enhancing NBF and lowering microvascular resistance. Continuous measurements of endoneurial oxygen and pH tension failed to identify associated declines with stimulation irrespective of the protocol. Both oxygen tension and pH tended to rise with stimulation. These studies confirm the presence of stimulation-induced endoneurial hyperemia but provide no evidence that local hypoxia or acidosis are mechanisms. Stimulation recruitment of vasodilatory axons innervating vasa nervorum may be an alternative explanation.
我们研究了分级神经干刺激对大鼠坐骨神经神经内膜血流（NBF）、氧张力和pH值的影响。本研究的目的是探索轴突代谢激活后其体内微环境的变化。在箭毒化的动物中，我们使用神经内膜微电极在不同刺激方案实施前、期间和之后进行了连续测量。刺激可增加NBF，且该效应与刺激串的频率、时长和强度直接相关。在旨在超最大程度募集有髓纤维的强度下，高频（50和100 Hz）和长时间（5 - 15分钟）刺激可增加NBF。利多卡因在刺激部位浸润可部分阻断该效应。旨在募集无髓纤维的高强度刺激在增强NBF和降低微血管阻力方面特别有效。无论采用何种方案，对神经内膜氧和pH张力的连续测量均未发现刺激后相关指标下降。氧张力和pH值在刺激时均趋于升高。这些研究证实了刺激诱导的神经内膜充血的存在，但没有证据表明局部缺氧或酸中毒是其机制。支配神经血管的血管舒张轴突的刺激募集可能是另一种解释。
