Differential contribution of GABAergic and glycinergic components to inhibitory synaptic transmission in lamina II and laminae III-IV of the young rat spinal cord
Differential contribution of GABAergic and glycinergic components to inhibitory synaptic transmission in lamina II and laminae III-IV of the young rat spinal cord
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DOI：
10.1111/j.1460-9568.2007.05919.x
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发表时间：
2007-11-01
影响因子：
3.4
通讯作者：
Schlichter, Remy
中科院分区：
文献类型：
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作者：
Inquimbert, Perrine;Rodeau, Jean-Luc;Schlichter, Remy
使用全细胞膜片钳记录从脊髓切片的年轻（10-15天）大鼠，我们的特点和比较的抑制性突触传递在板层II和板层III-IV的背角，这是参与伤害性和非伤害性的感觉信息的处理，分别。所有（100%）的板层III-IV神经元，但只有55%的板层II神经元，接受γ-氨基丁酸（GABA）能和甘氨酸能输入。其余45%的板层II神经元只接受GABA能突触。从未观察到仅接受甘氨酸能突触的神经元。在接受GABA能和甘氨酸能输入的55%的板层II神经元中，所有神经元都显示出一小部分（类似于10%）的混合微型抑制性突触后电流（mIPSC），表明在突触的子集处存在功能性GABA/甘氨酸共传递。这种共传输从未观察到在板层III-IV神经元。混合mIPSC的存在以及层II和层III-IV之间GABA（A）型受体mIPSC的衰减动力学的差异是由于层II中3 α 5 α还原类固醇（3 α 5 α-RS）的内源性紧张性产生。刺激3 α 5 α-RS的局部生产是可能的，在板层III-IV孵育后的切片与孕酮，皮下注射孕酮或诱导外周炎症。这导致GABA能mIPSC的延长，但未能诱导混合mIPSC在层III-IV中的出现。我们的研究结果表明，与板层II相比，在板层III-IV中的抑制性突触传递的特征在于甘氨酸能抑制的主导作用和功能性GABA/甘氨酸共传递的情况下。
Using whole-cell patch-clamp recordings from spinal cord slices of young (10-15 days old) rats, we have characterized and compared the properties of inhibitory synaptic transmission in lamina II and laminae III-IV of the dorsal horn, which are involved in the processing of nociceptive and non-nociceptive sensory information, respectively. All (100%) of laminae III-IV neurons, but only 55% of lamina II neurons, received both gamma-aminobutyric acid (GABA)ergic and glycinergic inputs. The remaining 45% of lamina II neurons received only GABAergic synapses. Neurons receiving only glycinergic synapses were never observed. Among the 55% of lamina II neurons receiving both GABAergic and glycinergic inputs, all displayed a small proportion (similar to 10%) of mixed miniature inhibitory postsynaptic currents (mIPSCs), indicating the presence of a functional GABA/glycine co-transmission at a subset of synapses. Such a co-transmission was never observed in laminae III-IV neurons. The presence of mixed mIPSCs and the differences in decay kinetics of GABA(A)-type receptor mIPSCs between lamina II and laminae III-IV were due to the endogenous tonic production of 3 alpha 5 alpha-reduced steroids (3 alpha 5 alpha-RS) in lamina II. Stimulation of the local production of 3 alpha 5 alpha-RS was possible in laminae III-IV after incubation of slices with progesterone, subcutaneous injection of progesterone or induction of a peripheral inflammation. This led to the prolongation of GABAergic mIPSCs, but failed to induce the appearance of mixed mIPSCs in laminae III-IV. Our results indicate that, compared with lamina II, inhibitory synaptic transmission in laminae III-IV is characterized by a dominant role of glycinergic inhibition and the absence of a functional GABA/glycine co-transmission.