Mixed GABA-glycine synapses delineate a specific topography in the nucleus tractus solitarii of adult rat
Mixed GABA-glycine synapses delineate a specific topography in the nucleus tractus solitarii of adult rat
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DOI：
10.1113/jphysiol.2009.184838
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发表时间：
2010-04-01
影响因子：
5.5
通讯作者：
Baude, Agnes
中科院分区：
文献类型：
--
作者：
Dufour, Amandine;Tell, Fabien;Baude, Agnes
使用相结合的形态学和电生理学的方法，我们已经确定了孤束核（NTS），脑干结构，是许多内脏感觉传入纤维的网关的抑制性突触的组成。免疫组织化学实验表明，在成年大鼠，GABA轴突终末存在于整个NTS，而混合GABA-甘氨酸轴突终末严格位于孤束周围的亚核内的NTS的外侧部分。孤束核外侧部的甘氨酸轴突终末较少，内侧部的甘氨酸轴突终末几乎不存在。电生理学实验证实了GABA抑制在整个NTS中的优势，并证明了存在双重抑制，涉及限制在NTS的侧部的GABA和甘氨酸的共同释放。由于GABA（A）和甘氨酸受体在整个NTS中几乎所有抑制性轴突终末中突触后共表达，这表明抑制表型依赖于轴突终末的特征。我们的研究结果还表明，甘氨酸主要是与GABA轴突终末内，并提高了GABA/甘氨酸释放的突触前水平的动态调节的可能性。我们的数据为了解成年动物中枢神经系统处理内脏信息的机制提供了新的信息。
Using combined morphological and electrophysiological approaches, we have determined the composition of inhibitory synapses of the nucleus tractus solitarii (NTS), a brainstem structure that is a gateway for many visceral sensory afferent fibres. Immunohistochemical experiments demonstrate that, in adult rat, GABA axon terminals are present throughout the NTS while mixed GABA-glycine axon terminals are strictly located to the lateral part of the NTS within subnuclei surrounding the tractus solitarius. Purely glycine axon terminals are rare in the lateral part of the NTS and hardly detected in its medial part. Electrophysiological experiments confirm the predominance of GABA inhibition throughout the NTS and demonstrate the existence of a dual inhibition involving the co-release of GABA and glycine restricted to the lateral part of NTS. Since GABA(A) and glycine receptors are co-expressed postsynaptically in virtually all the inhibitory axon terminals throughout the NTS, it suggests that the inhibition phenotype relies on the characteristics of the axon terminals. Our results also demonstrate that glycine is mostly associated with GABA within axon terminals and raise the possibility of a dynamic regulation of GABA/glycine release at the presynaptic level. Our data provide new information for understanding the mechanisms involved in the processing of visceral information by the central nervous system in adult animals.