INHIBITORY NEUROTRANSMISSION IN RAT SPINAL-CORD - COLOCALIZATION OF GLYCINE-RECEPTOR AND GABA(A)-RECEPTOR AT GABAERGIC SYNAPTIC CONTACTS DEMONSTRATED BY TRIPLE IMMUNOFLUORESCENCE STAINING
INHIBITORY NEUROTRANSMISSION IN RAT SPINAL-CORD - COLOCALIZATION OF GLYCINE-RECEPTOR AND GABA(A)-RECEPTOR AT GABAERGIC SYNAPTIC CONTACTS DEMONSTRATED BY TRIPLE IMMUNOFLUORESCENCE STAINING
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DOI：
10.1016/0006-8993(94)90905-9
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发表时间：
1994-04-11
期刊：
影响因子：
2.9
通讯作者：
FRITSCHY, JM
中科院分区：
文献类型：
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作者：
BOHLHALTER, S;MOHLER, H;FRITSCHY, JM
大鼠脊髓的突触抑制是由氨基酸γ-氨基丁酸(GABA)和甘氨酸介导的。大多数脊髓神经元对这两种神经递质都有反应，这表明GABA(A)敏感的甘氨酸受体和士的宁敏感的甘氨酸受体在单个细胞中共同表达。虽然甘氨酸受体的分布已经得到了广泛的表征，但对于GABA(A)受体在脊髓神经元中的细胞定位还知之甚少。在本研究中，用识别α1亚基的亚基特异性抗血清对GABA(A)受体的分布进行了免疫组织化学分析。用抗93 kDa甘氨酸受体相关蛋白的单抗和谷氨酸脱羧酶的抗血清，在激光共聚焦显微镜下观察它们与甘氨酸受体的共定位及其与GABA能轴突终末的结合。GABA(A)受体α1亚单位染色装饰了脊髓III-和X板层内大量神经元的胞体和树突，清晰地显示了它们的形态。双标免疫荧光染色显示，第III-VIII层和第X层的大多数GABA(A)受体阳性细胞也表现出明显的甘氨酸受体免疫反应。这两种类型的受体在细胞膜上的分布模式非常相似，并且经常共同定位于与GABA能轴突终末相对的位置。这些结果表明，GABA(A)受体和甘氨酸受体可能在单个突触后密度内共存，提示GABA和甘氨酸在脊髓神经元中的作用可能存在协同作用。
Synaptic inhibition in rat spinal cord is mediated by the amino acids gamma-aminobutyric acid (GABA) and glycine. Most spinal cord neurons respond to both neurotransmitters, suggesting co-expression of GABA(A)- and strychnine-sensitive glycine-receptors in individual cells. While the distribution of glycine-receptors has been extensively characterized, much less is known about the cellular localization of GABA(A)-receptors in spinal cord neurons. In the present study, the distribution of GABA(A)-receptors was analyzed immunohistochemically with a subunit-specific antiserum recognizing the alpha 1-subunit. Their co-localization with glycine-receptors and their apposition to GABAergic axon terminals were assessed by confocal laser microscopy in sections processed for double- and triple-immunofluorescence staining, using a monoclonal antibody against the 93 kDa glycine-receptor-associated protein, gephyrin, and an antiserum to glutamic acid decarboxylase. Staining for the GABA(A)-receptor alpha 1-subunit decorated the soma and dendrites of numerous neurons in laminae III-VIII and X of the spinal cord, revealing their morphology in clear detail. By contrast, laminae II and IX contained little immunoreactivity for these GABA(A)-receptors, Double-immunofluorescence staining showed that most GABA(A)-receptor-positive cells in layers III-VIII and X also exhibited a prominent glycine-receptor immunoreactivity. Both types of receptors had very similar distribution patterns in the cell membrane and were frequently co-localized in sites apposed to GABAergic axon terminals. These results indicate that GABA(A)- and glycine-receptors may co-exist within single postsynaptic densities, suggesting a possible synergism in the action of GABA and glycine in spinal cord neurons.