Roederer E, Cohen M J
J Neurosci. 1983 Sep;3(9):1835-47. doi: 10.1523/JNEUROSCI.03-09-01835.1983.
When the axon of the medial giant interneuron (MGI) of the cricket is axotomized close to the cell body, the normally stable, characteristic dendritic arborization is induced to sprout supernumerary neurites. The origin of the induced dendritic sprouts is not random; they emerge preferentially from the dentritic tips and branches close to the exit of the axon from the terminal ganglion. If any growth also occurred from the axon, there was a reciprocal relationship between the extent of dendritic and axonal sprouting. On the other hand, axotomy distant to the cell body induces sprouting only from the axon and does not alter the dendritic structure of the MGI. After crushing the ventral nerve cord distant to the cell body, the MGI sprouted neurites from the proximal axonal stump which crossed the site of lesion and continued growing within the distal cord. After a distant cut of the cord, however, the axonal neurites formed a neuroma in the proximal cord stump at the site of lesion and stopped elongating after 1 month. At this time, supernumerary sprouts first began to emerge from the normally smooth, rounded contours of the cell body. Based on these observations, we propose that axotomized neurons produce membrane at a constant rate. This newly synthesized membrane is preferentially inserted into neurites emerging from the proximal axonal stump. When axonal neurites stop growing in a neuroma following a distant cut, then this new membrane appears as supernumerary neurites from the soma. After a close cut, the axon often dies back into the ganglion and appears unable to receive the full complement of sprouting membrane. In such cases, the balance of the newly synthesized membrane is inserted into the dendrites and the characteristic structure of the arborization is significantly altered.
当蟋蟀的内侧巨中间神经元（MGI）的轴突在靠近细胞体处被切断时，其通常稳定的特征性树突分支会被诱导长出多余的神经突。诱导产生的树突芽的起源并非随机；它们优先从靠近轴突从终神经节穿出部位的树突尖端和分支处出现。如果轴突也有任何生长，那么树突和轴突的发芽程度之间存在相互关系。另一方面，在远离细胞体处进行轴突切断仅诱导轴突发芽，而不会改变MGI的树突结构。在远离细胞体处挤压腹神经索后，MGI从近端轴突残端长出神经突，这些神经突穿过损伤部位并在远端神经索内继续生长。然而，在神经索进行远距离切断后，轴突神经突在损伤部位的近端神经索残端形成神经瘤，并在1个月后停止伸长。此时，多余的芽首先开始从细胞体通常光滑、圆润的轮廓处出现。基于这些观察结果，我们提出轴突被切断的神经元以恒定速率产生膜。这种新合成的膜优先插入从近端轴突残端长出的神经突中。当轴突神经突在远距离切断后在神经瘤中停止生长时，那么这种新膜就会以细胞体多余神经突的形式出现。在进行近距离切断后，轴突常常会回缩到神经节中，似乎无法接收全部的发芽膜。在这种情况下，新合成膜的平衡会插入到树突中，树突分支的特征结构会发生显著改变。
