Effects of peripheral axotomy on presynaptic axon terminals with GABA-like immunoreactivity.
Effects of peripheral axotomy on presynaptic axon terminals with GABA-like immunoreactivity.
复制标题
外周轴突切开术对具有 GABA 样免疫反应性的突触前轴突末端的影响。
DOI：
10.1002/ar.1092380211
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Vaughan,DW
中科院分区：
文献类型：
--
作者：
Vaughan,DW
3只3月龄雄性大鼠面神经在茎乳孔出口处发生单侧挤压。存活10天后，在再生轴突重新支配其靶肌肉之前，检查面神经核以确定中央反应模式，这些材料是为证明GABA样免疫反应的存在而准备的材料，包埋后的程序使用金标记次抗体。未损伤的核团作为对照。在对照核和损伤核中，GABA能终末与运动神经元的所有部分(轴突除外)突触，并呈现出不同的形态。GABA能轴突终末的大小和轴浆的电子密度各不相同，大多数终末含有多形性的囊泡，显示出不同的堆积密度和大小。在对照组和损伤面神经核中，仅有40%的带有多形性小泡的轴突终末轮廓显示∼免疫反应阳性。对GABA阳性终末突触小泡轮廓的形态计量学分析表明，切断轴突后，每个GABA能终末轮廓的突触小泡轮廓的平均数没有变化。然而，这些终末的突触小泡轮廓的平均大小在轴突切断后增加了50%，而增大的小泡轮廓的形状没有改变。此外，与GABA阳性终末相关的金颗粒在损伤轴突终末的数密度始终大于对照轴突终末。在对照动物中，所有轴突终末轮廓在神经束中的相对分布按其囊泡轮廓的形状分为圆形、多形性和平坦型为57：37：6。轴突切断10天后，这些类别在受损核中的比例已移动到35：60：5。本研究表明，突触后靶点的功能状态可以影响突触前元件中的囊泡轮廓的形态及其传入输入的模式。©1994 Wiley-Liss，Inc.
The facial nerve was unilaterally crushed at its exit from the stylomastoid foramen in three 3‐month old male rats. After 10 days survival, before the regenerating axons had reinnervated their target muscles, the facial nucleus was examined to determine central patterns of response in material prepared to demonstrate the presence of GABA‐like immunoreactivity with postembedding procedures using gold‐labeled secondary antibody. The uninjured nucleus served as a control. In both control and injured nuclei, the GABAergic terminals synapse with all parts of the motor neurons, except the axon, and exhibit diverse morphologies. GABAergic axon terminals vary in their size and in the electron density of their axoplasm and the majority of the terminals contain pleomorphic vesicle profiles that display a range in their packing density and size. In both control and injured facial nuclei, only ∼40% of the axon terminal profiles with pleomorphic vesicles exhibit GABA immunoreactivity. A morphometric analysis of the synaptic vesicle profiles in the GABA‐positive terminals reveals that following axotomy there is no change in the mean number of synaptic vesicle profiles per GABAergic terminal profile. However, the mean size of the synaptic vesicle profiles in these terminals shows an axotomy‐induced 50% increase, without change in the shapes of the enlarged vesicle profiles. Also, the numerical density of gold particles associated with the GABA‐positive terminals is consistently greater in the injured than the control axon terminals. In the control animals quantitative analysis of the relative distribution of all axon terminal profiles in the neuropil categorized by the shape of their vesicle profiles as round, pleomorphic, or flat is 57:37:6. Ten days after axotomy the ratio of these categories in the injured nucleus has shifted to 35:60:5. This study demonstrates that the functional state of a postsynaptic target can influence the morphology of vesicle profiles in presynaptic elements as well as patterns of its afferent input. © 1994 Wiley‐Liss, Inc.