Department of Physiology, University College London, London, UK.
J Physiol. 2011 Feb 1;589(Pt 3):559-73. doi: 10.1113/jphysiol.2010.201376. Epub 2010 Nov 22.
In the central nervous system, electrical signals passing along nerve cells are speeded by cells called oligodendrocytes, which wrap the nerve cells with a fatty layer called myelin. This layer is important for rapid information processing, and is often lost in disease, causing mental or physical impairment in multiple sclerosis, stroke, cerebral palsy and spinal cord injury. The myelin speeds the information flow in two ways, by decreasing the capacitance of the nerve cell and by increasing its membrane resistance, but little is known about the latter aspect of myelin function. By recording electrically from oligodendrocytes and imaging their morphology we characterised the geometry and, for the first time, the resistance of myelin in the brain. This revealed differences between the properties of oligodendrocytes in two brain areas and established that the resistance of myelin is sufficiently high to prevent significant slowing of the nerve electrical signal by current leakage through the myelin.
在中枢神经系统中，电信号沿着神经细胞传递的速度可以通过被称为少突胶质细胞的细胞来加速，少突胶质细胞用一层称为髓鞘的脂肪层包裹神经细胞。髓鞘对于快速信息处理很重要，并且在多发性硬化症、中风、脑瘫和脊髓损伤等疾病中经常丢失，导致精神或身体损伤。髓鞘通过两种方式加速信息流，即降低神经细胞的电容和增加其膜电阻，但对髓鞘功能的后一方面知之甚少。通过对少突胶质细胞进行电记录并对其形态进行成像，我们描述了髓鞘的几何形状，并首次描述了大脑中髓鞘的电阻。这揭示了两个大脑区域中少突胶质细胞性质的差异，并确定了髓鞘的电阻足够高，可以防止电流通过髓鞘泄漏对神经电信号造成明显的减速。
