Blaker W D, Goodrum J F, Morell P
J Cell Biol. 1981 Jun;89(3):579-84. doi: 10.1083/jcb.89.3.579.
Rats 24 d old were injected intraocularly with [2-3H]glycerol and [35S]methionine and killed 1 h-60 d later. 35S label in protein and 3H label in total phospholipid and a mitochondria-specific lipid, diphosphatidylglycerol(DPG), were determined in optic pathway structures (retinas, optic nerves, optic tracts, lateral geniculate bodies, and superior colliculi). Incorporation of label into retinal protein and phospholipid was nearly maximal 1 h postinjection, after which the label appeared in successive optic pathway structures. Based on the time difference between the arrival of label in the optic tract and superior colliculus, it was calculated that protein and phospholipid were transported at a rate of about 400 mm/d, and DPG at about half this rate. Transported labeled phospholipid and DPG, which initially comprised 3-5% of the lipid label, continued to accumulate in the visual structures for 6-8 d postinjection. The distribution of transported material among the optic pathway structures as a function of time differed markedly for different labeled macromolecules. Rapidly transported proteins distributed preferentially to the nerve endings (superior colliculus and lateral geniculate). Total phospholipid quickly established a pattern of comparable labeling of axon (optic nerve and tract) and nerve endings. In contrast, the distribution of transported labeled DPG gradually shifted toward the nerve ending and stabilized by 2-4 d. A model is proposed in which apparent "transport" of mitochondria is actually the result of random bidirectional saltatory movements of individual mitochondria which equilibrate them among cell body, axon, and nerve ending pools.
给24日龄的大鼠眼内注射[2-³H]甘油和[³⁵S]甲硫氨酸，1小时至60天后处死。测定了视路结构（视网膜、视神经、视束、外侧膝状体和上丘）中蛋白质中的³⁵S标记以及总磷脂和线粒体特异性脂质二磷脂酰甘油（DPG）中的³H标记。注射后1小时，视网膜蛋白质和磷脂中的标记掺入几乎达到最大值，之后标记出现在连续的视路结构中。根据标记到达视束和上丘的时间差计算得出，蛋白质和磷脂的运输速率约为400毫米/天，DPG的运输速率约为其一半。运输的标记磷脂和DPG最初占脂质标记的3%-5%，在注射后6-8天内继续在视觉结构中积累。不同标记大分子在视路结构中的运输物质分布随时间的变化明显不同。快速运输的蛋白质优先分布到神经末梢（上丘和外侧膝状体）。总磷脂迅速在轴突（视神经和视束）和神经末梢建立了相当的标记模式。相比之下，运输的标记DPG的分布逐渐向神经末梢转移，并在2-4天内稳定下来。提出了一个模型，其中线粒体的明显“运输”实际上是单个线粒体随机双向跳跃运动的结果，这些运动使它们在细胞体、轴突和神经末梢池之间达到平衡。
