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首页> 外文期刊>The European Journal of Neuroscience >Gamma amino butyric acid (GABA) immunoreactivity in the vestibular nuclei of normal and unilateral vestibular neurectomized cats.
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Gamma amino butyric acid (GABA) immunoreactivity in the vestibular nuclei of normal and unilateral vestibular neurectomized cats.

机译：正常和单侧前庭神经切除猫的前庭核中的γ-氨基丁酸（GABA）免疫反应性。

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摘要

Recent neurochemical investigations of the central vestibular pathways have demonstrated that several neurotransmitters are involved in various operations required for stabilizing posture and gaze. Neurons of the vestibular nuclei (VN) receive GABAergic inhibitory afferents, and GABAergic neurons distributed throughout the vestibular complex are implicated in inhibitory vestibulo-ocular and vestibulo-spinal pathways. The aim of this study was to analyse the modifications of GABA immunoreactivity (GABA-ir) in the cat VN after unilateral vestibular neurectomy (UVN). Indeed, compensation of vestibular deficits is a good model for studying adult central nervous system (CNS) plasticity and the GABAergic system is involved in CNS plasticity. We studied GABA-ir by using a purified polyclonal antibody raised against GABA. Light microscopic preparations of thin (20 microm) sections of cat VN were used to quantify GABA-ir by an image analysing system measuring GABA-positive punctate structures and the number of GABA-positive neurons. Both the lesioned and intact sides were analysed in three populations of UVN cats killed at different times after injury (1 week, 3 weeks and 1 year). These data were compared to those collected in normal unlesioned and sham-operated cats. Results showed a spatial distribution of GABA-ir in the control cats that confirmed previous studies. GABA-ir neurons, fibres and nerve terminals were scattered in all parts of the VN. A higher concentration of GABA-positive neurons (small cells) was detected in the medial and inferior VN (MVN and IVN) and in the dorsal part of the lateral VN (LVNd). A higher level of GABA-positive punctate structures was observed in the MVN and in the prepositus hypoglossi (PH) nucleus. Lesion-induced changes were found at each survival time. One week after injury the number of GABA-positive neurons was significantly increased in the MVN, the IVN and the dorsal part of the LVN on the lesioned side and in the ventral part of the LVN on the intact side. One year later a bilateral increase in GABA-positive neurons was detected in the MVN whilst a bilateral decrease was observed in both the SVN and the ventral part of the LVN. Changes in the GABA-staining varicosities did not strictly coincide with the distribution of GABA-ir cells, suggesting that GABA-ir fibres and nerve terminals were also modified. One week and later after injury, higher GABA-staining varicosities were seen unilaterally in the ipsilateral MVN. In contrast, bilateral increases (in PH) and bilateral decreases (in SVN and the ventral part of the LVN) were recorded in the nearly (3 weeks) or fully (1 year) compensated cats. At this stage GABA-staining varicosities were significantly increased in the lesioned side of the MVN. These findings demonstrate the reorganization of the GABAergic system in the VN and its possible role in recovery process after UVN in the cat. The changes seen during the acute stage could be causally related to the VN neuron deafferentation, contributing to the static vestibular deficits. Those found in the compensated cats would be more functionally implicated in the dynamic aspects of vestibular compensation.
机译：最近对中枢前庭通路的神经化学研究表明，几种神经递质参与稳定姿势和凝视所需的各种操作。前庭核（VN）的神经元接受GABA能抑制传入，并且分布在整个前庭复合体中的GABA能神经元与抑制性前庭眼和前庭脊髓通路有关。这项研究的目的是分析单侧前庭神经切除术（UVN）后猫VN中GABA免疫反应性（GABA-ir）的变化。实际上，前庭功能不全的补偿是研究成人中枢神经系统（CNS）可塑性的良好模型，而GABA能系统参与了CNS可塑性。我们通过使用针对GABA的纯化多克隆抗体研究了GABA-ir。通过测量GABA阳性点状结构和GABA阳性神经元数量的图像分析系统，将猫VN薄（20微米）切片的光学显微镜制剂用于定量GABA-ir。在受伤后不同时间（1周，3周和1年）对三只UVN猫种群的病变侧和完整侧进行了分析。将这些数据与在正常病变和假手术猫中收集的数据进行比较。结果表明，对照猫中GABA-ir的空间分布证实了先前的研究。 GABA-ir神经元，纤维和神经末梢散布在VN的所有部位。在内侧和下部VN（MVN和IVN）和外侧VN的背侧部分（LVNd）中检测到较高浓度的GABA阳性神经元（小细胞）。在MVN和垂体前叶（PH）核中观察到更高水平的GABA阳性点状结构。在每个生存时间发现病变引起的变化。损伤后一周，病变侧的MVN，IVN和LVN的背侧以及完整侧的LVN腹侧的GABA阳性神经元数量显着增加。一年后，在MVN中检测到GABA阳性神经元双侧增加，而在SVN和LVN腹侧均观察到双侧减少。 GABA染色静脉曲张的变化与GABA-ir细胞的分布并不严格一致，这表明GABA-ir纤维和神经末梢也被修饰。受伤后一周和之后，在同侧MVN中单侧观察到较高的GABA染色静脉曲张。相比之下，在补偿后近（3周）或完全补偿（1年）的猫中记录了双侧增加（PH）和双侧减少（SVN和LVN腹侧部分）。在此阶段，MVN病变侧的GABA染色静脉曲张明显增加。这些发现证明了在猫中，VN中GABA能系统的重组及其在UVN术后恢复过程中的可能作用。急性期所见的变化可能与VN神经元脱除咖啡因有因果关系，从而导致静态前庭缺损。在补偿后的猫中发现的那些在功能上与前庭补偿的动态方面有关。

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