Axons of sacral preganglionic neurons in the cat: II. Axon collaterals.
Axons of sacral preganglionic neurons in the cat: II. Axon collaterals.
复制标题
猫骶神经节前神经元的轴突：II。
DOI：
10.1023/a:1019637304031
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Morgan,CW
中科院分区：
文献类型：
--
作者：
Morgan,CW
轴突侧支被确定在21的24节前神经元在外侧带的猫骶副交感神经核。HRP或神经生物素的细胞内注射后，这些神经元的轴突从20个被跟踪和53个初级轴突侧支被发现起源于无髓段和从节点的Ranvier。在5个标记最好的细胞中进行的详细绘图显示，双侧轴突侧支分布长度达25，000 μm，有950处静脉曲张，单侧分布长度达12，561 μm，有491处静脉曲张。轴突侧支无髓鞘，直径小（平均0.3 μm）。静脉曲张主要位于第I、V、VII、VIII、X层和外侧索。大多数静脉曲张不与可见结构接触，但有些静脉曲张与尼氏染色的胞体和近端树突紧密贴壁。静脉曲张的平均小直径为1.3 μm，大直径为2.3 μm。绝大多数为过路钮，10-20%为终钮。电镜下可见由静脉曲张和静脉曲张间轴突形成的轴-树-轴突触和轴-轴突触。据估计，这些轴突侧支系统中最广泛的轴突侧支系统可以在多个位置接触超过200个脊髓神经元。这些数据导致的结论是，骶节前神经元在脊髓内有多种功能，除了为他们的靶器官。由于该位置的大多数节前神经元支配膀胱，因此膀胱节前神经元可能具有多种功能。
Axon collaterals were identified in 21 of 24 preganglionic neurons in the lateral band of the sacral parasympathetic nucleus of the cat. Following the intracellular injection of HRP or neurobiotin the axons from 20 of these neurons were followed and 53 primary axon collaterals were found to originate from unmyelinated segments and from nodes of Ranvier. Detailed mapping done in the five best labeled cells showed bilateral axon collaterals distributions up to 25,000 μm in length with 950 varicosities and unilateral distributions up to 12,561 μm with 491 varicosities. The axon collaterals appeared to be unmyelinated, which was confirmed at EM, and were small in diameter (average 0.3 μm). Varicosities were located mostly in laminae I, V, VII, VIII and X and in the lateral funiculi. Most varicosities were not in contact with visible structures but some were seen in close apposition to Nissl stained somata and proximal dendrites. Varicosities had average minor diameters of 1.3 μm and major diameters of 2.3 μm. Most were boutons en passant while 10–20% were boutons termineaux. EM revealed axodendritic and axoaxonic synapses formed by varicosities and by the axons between varicosities. It is estimated that the most extensive of these axon collaterals systems may contact over 200 spinal neurons in multiple locations. These data lead to the conclusion that sacral preganglionic neurons have multiple functions within the spinal cord in addition to serving their target organ. As most preganglionic neurons in this location innervate the urinary bladder, it is possible that bladder preganglionic neurons have multiple functions.