Studies of specific treatment strategies utilizing axoplasmic transpot in motor neuron diseases.

为了探讨利用逆行轴浆转运现象治疗肌萎缩性侧索硬化症的可能性，初步研究其内在转运机制。本研究阐明了位于脊髓前角的躯体运动神经元通过神经肌肉接点的逆行轴浆转运，生理性地摄取血清白蛋白和IgG。形成神经肌肉连接处的细胞外基质被认为在为初始摄取提供储存库中起作用，细胞外基质的组成蛋白被检查。层粘连蛋白是基质的主要蛋白质之一，已知具有许多功能域，其中之一是强大的神经营养作用。当用抗层粘连蛋白抗体对运动神经元进行免疫细胞化学研究时，运动神经元有明显的免疫反应性。对大鼠和人脑匀浆进行Western blot，发现了与正宗层粘连蛋白具有相同抗原性的l9OkDalton蛋白。将CNS中的层粘连蛋白与真实的层粘连蛋白进行比较，发现在还原条件下，神经层粘连蛋白不具有亚基，分子量接近层粘连蛋白B链。然而，当使用肝素亲和柱时，神经胺素中未出现肝素结合结构域。同样，神经胺素似乎不是细胞外的度量成分，而是细胞内的分子。这项研究正在进行中，目的是纯化神经胺素，并观察这种特殊分子中存在的生物活性。如果神经胺素确实具有神经营养活性，那么通过逆行轴浆运输系统治疗肌萎缩性侧索硬化症患者可能是值得尝试的分子。

In order to investigate the possibility of treating the patients with amyotrophic lateral sclerosis, utilizing the phenomenon of retrograde axoplasmic transport, intrinsic transport mechanism was initially studied. This study clarified the somatic motor neurons residing in the spinal anterior horn physiologically take up serum albumin and IgG by way of retrograde axoplasmic transport from the neuromuscular junction. Extracellular matrix forming the neuromuscular junction was then thought to play a role in subserving the reservoir for initial uptake, constituent proteins of the extracellular matrix were examined. Laminin, one of major proteins of the matrix, is known to possess many functional domains, one of which is a potent neurotrophic actions. When motor neurons were immunocytochemically studies with anti-laminin antibody, there was a distinct immunoreactivity in motor neurons. Western blot of the brain homogenates in rat and human disclosed l9OkDalton protein which shares the antigenicity with authentic laminin was found. When the laminin in the CNS (neurolaminin) was compared to authentic laminin, it was found that neurolaminin did not possess subunits under reducing condition and the molecular weight is close to laminin B chain. However, heparin-binding domain appeared not present in neurolaminin, when heparin-affinity column was used. Similarly, neurolaminin did not appear to be an extracellular metric constituent but intra cellular molecule. The study is in progress in order to purify neurolaminin and to see the biological activities which are assumed to be present in this particular molecule. If indeed neurolaminin possesses neurotrophic activity this molecule might be the one which is worthwhile trying to treat the patients with amyotrophic lateral sclerosis, by way of retrograde axoplasmic transport system.