Alberghina M, Viola M, Giuffrida A M
J Neurochem. 1983 Jan;40(1):25-31. doi: 10.1111/j.1471-4159.1983.tb12648.x.
The intraaxonal transport of phospholipids in regenerating hypoglossal nerve of the rabbit was investigated by administration of labeled lipid precursors into the medulla oblongata. At various time intervals after crushing the left hypoglossal nerve at the level of the digastric muscle, a mixture of 60 mu Ci of [2-3H]glycerol and 15 mu Ci of [1-14C]palmitate, dissolved in 15% bovine serum albumin, was injected into the calamus scriptorius of the fourth ventricle. The amount and the pattern of labeling of glycerophospholipids synthesized in the motor neurons were determined. Three days after nerve crush there was an accumulation of labeled glycerophospholipids immediately proximal to the injury site. Seven days after crushing, the regenerating nerve incorporated rapidly transported labeled lipids in greater amounts than the contralateral normal nerve; the incorporation was elevated along the entire length of the nerve containing both regenerating axons and the post-crush sprouting terminals. The difference between the two sides increased up to 14 days, but disappeared as regeneration proceeded (21-45 days). The "pool" of radioactive lipids remaining in the cell bodies of hypoglossal nuclei, in the segments of nerve, both proximal and distal to the crush site, and in all the segments of uncrushed nerve was similar 6-12 h after labeling. Among the phospholipids, the highest 3H and 14C radioactivity was observed in phosphatidylcholine and phosphatidylethanolamine. These results support the hypothesis than an increase in the amount of glycerophospholipids, conveyed by rapid axonal transport, takes place in the first 2 weeks during nerve regeneration. The increased transport of lipids presumably reflects an augmented demand for membrane precursors during the sprouting process.
通过向延髓注射标记的脂质前体，研究了家兔再生舌下神经中磷脂的轴突内运输。在二腹肌水平切断左侧舌下神经后的不同时间间隔，将溶解于15%牛血清白蛋白中的60μCi [2-³H]甘油和15μCi [1-¹⁴C]棕榈酸的混合物注入第四脑室的髓纹。测定运动神经元中合成的甘油磷脂的标记量和模式。神经挤压后三天，损伤部位近端立即出现标记甘油磷脂的积累。挤压后七天，再生神经比同侧正常神经更快地摄取大量快速运输的标记脂质；在包含再生轴突和挤压后发芽终末的整个神经长度上，摄取量都有所增加。两侧的差异在14天前不断增大，但随着再生的进行（21 - 45天）而消失。标记后6 - 12小时，舌下神经核细胞体、挤压部位近端和远端的神经节段以及未挤压神经的所有节段中残留的放射性脂质“池”相似。在磷脂中，磷脂酰胆碱和磷脂酰乙醇胺的³H和¹⁴C放射性最高。这些结果支持这样的假说，即在神经再生的前两周内，通过快速轴突运输传递的甘油磷脂量会增加。脂质运输的增加可能反映了发芽过程中对膜前体的需求增加。
