Growth cones and structural variation of synaptic end-bulbs in the cochlear nucleus of the adult cat brain.
Growth cones and structural variation of synaptic end-bulbs in the cochlear nucleus of the adult cat brain.
复制标题
成年猫大脑耳蜗核中突触终球的生长锥和结构变化。
DOI：
10.1002/syn.890100404
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Morest,DK
中科院分区：
文献类型：
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作者：
Jones,DR;Hutson,KA;Morest,DK
为了探索突触结构变异和新生长的潜力，我们通过使用快速高尔基体、还原银和电子显微镜方法研究了成年猫耳蜗神经轴突末端的形态模式。辣根过氧化物酶标记的这些末端在前腹侧耳蜗核的前部是通过注射到耳蜗后的顺行运输产生的。无论采用哪种方法，都可以区分三种类型的端球：网状、聚结和环状形式，所有球状突触都在球形浓密细胞上。网状品种对应于经典描述的端球，并构成音位图所有区域的大多数。这里首次描述的环状端球在浓密细胞的主树突基部周围形成兴奋性突触袖带；这些末端位于接收 1-6 kHz 范围内的耳蜗输入的区域，该区域用于发声。在整个研究区域中，聚结末端仅占球茎末端数量的一小部分。这些发现提出了这些突触类型之间存在功能差异的可能性。在所研究的每只成年猫中，大多数（如果不是全部）末端灯泡上都存在生长锥和回缩球。对端球模式的系统调查揭示了变化的连续梯度，其中每种突触类型形成独特的模式。这些发现使我们假设球茎处于结构和功能不断变化的状态。这些结局对于研究中央突触的可修改特性应该是有用的。
To explore the potential for structural variation and new growth at the synapse, we studied the morphological patterns of the end‐bulbs of cochlear nerve axons in adult cats by using rapid Golgi, reduced silver, and electron microscopic methods. Horseradish peroxidase labeling of these endings in the anterior division of the antroventral cochlear nucleus was produced by anterograde transport following injection into the cochlea. Three types of end‐bulbs were distinguished, regardless of method: reticular, coalescent, and ringed forms, all synapsing on spherical bushy cells. The reticular variety corresponds to the classically described end‐bulb and constitutes the majority in all regions of the tonotopic map. The ringed end‐bulb, described here for the first time, forms an excitatory synaptic cuff around the base of a bushy cell's main dendrite; these endings were localized to the region receiving cochlear input in the 1–6 kHz range, which is used in vocalization. The coalescent ending forms a small fraction of the end‐bulb population throughout the region studied. The findings raise the possibility of functional differences between these snyaptic types.Growth cones and retraction clubs were present on most, if not all, of the end‐bulbs in every adult cat studied. A systematic survey of the end‐bulb patterns revealed a continuous gradient of variation, in which each synaptic type forms a distinct mode. These findings lead us to hypothesize that the end‐bulbs are in a continual state of structural and functional flux. These endings should prove useful for studies on the modifiable properties of central synapses.