GABA and glycine-like immunoreactivity at axoaxonic synapses on 1a muscle afferent terminals in the spinal cord of the rat
GABA and glycine-like immunoreactivity at axoaxonic synapses on 1a muscle afferent terminals in the spinal cord of the rat
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DOI：
10.1002/cne.1143
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发表时间：
2001-05-07
影响因子：
2.5
通讯作者：
Bazzaz, AA
中科院分区：
文献类型：
--
作者：
Watson, AHD;Bazzaz, AA
本研究的目的是分析大鼠脊髓中已确定的肌纺锤传入轴突末端的突触相互作用。将供应腓肠肌的la组肌肉传入神经用微电极刺入脊髓的背侧白质中，并通过细胞内注射神经生物素进行染色。包埋后免疫金技术用于揭示突触前到腹角传入末梢和背角深层的 GABA 和甘氨酸样免疫反应性。使用连续切片重建来揭示传入终端上不同类型突触接触的分布。大多数传入波顿接收轴轴并形成轴突或轴体突触接触。在腹角，91% 的突触前传入神经末梢仅对 GABA 具有免疫反应性，9% 对 GABA 和甘氨酸均具有免疫反应性。每个终端接收到的轴突接触的平均数量为 2.7，终端作为突触前元件的突触接触的平均数量为 1.4。在背角的深层，58%的突触前传入神经末梢对单独的GABA有免疫反应，31%的对GABA和甘氨酸有免疫反应，11%对单独的甘氨酸有免疫反应。该区域中每个传入终端接收到的轴轴接触的平均数量为 1.6，该终端作为突触前元件的突触接触的平均数量为 0.86。这清楚地确立了以下原理：传入神经的活动是由几个神经化学上不同的突触前神经元群体调节的。 (C) 2001 Wiley-Liss, Inc.
The object of this study was to analyze the synaptic interactions of identified muscle spindle afferent axon terminals in the spinal cord of the rat. Group la muscle afferents supplying the gastrocnemius muscle were impaled with microelectrodes in the dorsal white matter of the spinal cord and stained by intracellular injection with Neurobiotin. Postembedding immunogold techniques were used to reveal GABA- and glycine-like immunoreactivity in boutons presynaptic to afferent terminals in the ventral horn and the deep layers of the dorsal horn. Serial-section reconstruction was used to reveal the distribution of synaptic contacts of different types on the afferent terminals. The majority of afferent boutons received axoaxonic and made axodendritic or axosomatic synaptic contacts. In the ventral horn, 91% of boutons presynaptic to the afferent terminals were immunoreactive for GABA alone and 9% were immunoreactive for both GABA and glycine. The mean number of axo-axonic contacts received per terminal was 2.7, and the mean number of synaptic contacts at which the terminal was the presynaptic element was 1.4. In the deep layers of the dorsal horn, 58% of boutons presynaptic to afferent terminals were immunoreactive for GABA alone, 31% were immunoreactive for GABA and glycine, and 11% for glycine alone. The mean number of axoaxonic contacts received per afferent terminal in this region was 1.6 and the mean number of synaptic contacts at which the terminal was the presynaptic element was 0.86. This clearly establishes the principle that activity in la afferents is modulated by several neurochemically distinct populations of presynaptic neuron. (C) 2001 Wiley-Liss, Inc.