Three-dimensional organization of local excitatory and inhibitory inputs to neurons in laminae III-IV of the spinal dorsal horn.
Three-dimensional organization of local excitatory and inhibitory inputs to neurons in laminae III-IV of the spinal dorsal horn.
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脊髓背角 III-IV 层神经元局部兴奋性和抑制性输入的三维组织。
DOI：
10.1113/jphysiol.2013.256016
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Strassman,AndrewM
中科院分区：
文献类型：
--
作者：
Kato,Go;Kosugi,Masafumi;Mizuno,Masaharu;Strassman,AndrewM
要点•检测身体组织疼痛和非疼痛刺激的感觉神经元轴突集中投射到脊髓的背角，分别在浅层和深层中部分分离。•浅层和深层之间的神经元间连接可能会调节感觉传递，并有助于在疼痛过敏条件下发生的改变。•本研究使用局部刺激技术（激光扫描光刺激）进行高分辨率映射在大鼠腰脊髓的体外“切片”制备中，与第 III-IV 层神经元的局部神经元突触连接，结合用于形态分析的细胞内染色。•来自浅层 (I-II) 的突触输入由具有长背侧树突的第 III-IV 层神经元接收，支持了层间连接是通过跨层树突延伸介导的观点，更普遍的是，局部连接是受特定于突触后神经元的层状位置和形态的规则的控制。摘要激光扫描光刺激用于绘制大鼠腰脊髓的旁矢状和横向切片中背角层 III-IV 神经元的突触输入区（提供局部突触输入的位点）的分布，并检查这些输入对于不同形态的神经元有何不同。所有神经元均接收来自 III-IV 层内的局部兴奋性和抑制性突触输入，而一部分神经元还接收来自浅层（尤其是 IIi 层）以及 II/III 边界区域的兴奋性输入。研究发现，两个解剖学特性可以预测神经元输入区相对于体细胞的背腹侧位置：（1）对于具有较长背侧树突的神经元，兴奋性和抑制性输入区都更靠背；（2）对于更多腹侧神经元，兴奋性而非抑制性输入区更靠背（相对于体体），第 III-IV 层神经元的背侧输入区与腹侧之间有过渡。 II 层神经元的输入区出现在 II/III 边界。观察到的形态生理学相关性支持这样的观点，即层间连接是通过跨层树突延伸介导的，更一般地，背角内的局部连接受神经元胞体和树突位置与接收输入的局部突触前神经元位置的规则控制，这些输入特定于轴和方向（背腹），无论输入是兴奋性还是抑制性，以及突触后神经元的层状位置。
Key points•Axons of sensory neurons that detect painful and non‐painful stimulation of body tissues project centrally to the dorsal horn of the spinal cord, where they are partially segregated in the superficial and deep laminae, respectively.•Interneuronal connections between superficial and deep laminae could potentially modulate sensory transmission and contribute to alterations that occur under conditions of pain hypersensitivity.•This study used a localized stimulation technique (laser scanning photostimulation) for high‐resolution mapping of local interneuronal synaptic connections to laminae III–IV neurons, combined with intracellular staining for morphological analysis, in anin vitro‘slice’ preparation of the rat lumbar spinal cord.•Synaptic input from superficial laminae (I–II) was received by laminae III–IV neurons with long dorsal dendrites, supporting the idea that interlaminar connectivity is mediated via translaminar dendritic extensions and, more generally, that local connectivity is governed by rules that are specific to the laminar position and morphology of the postsynaptic neuron.AbstractLaser scanning photostimulation was used to map the distribution of the synaptic input zones (sites that give local synaptic inputs) for dorsal horn laminae III–IV neurons, in parasagittal and transverse slices of the rat lumbar spinal cord, and examine how these inputs differed for neurons of different morphologies. All neurons received local excitatory and inhibitory synaptic inputs from within laminae III–IV, while a subset of neurons also received excitatory input from the superficial laminae, especially lamina IIi, as well as the II/III border region. Two anatomical properties were found to be predictive of the dorsoventral position of a neuron's input zone relative to its soma: (1) both excitatory and inhibitory input zones were more dorsal for neurons with longer dorsal dendrites, and (2) excitatory, but not inhibitory, input zones were more dorsal (relative to the soma) for more ventral neurons, with the transition between the dorsal input zones of laminae III–IV neurons and the ventral input zones of lamina II neurons occurring at the II/III border. The observed morphophysiological correlations support the idea that interlaminar connectivity is mediated via translaminar dendritic extensions and that, more generally, local connectivity within the dorsal horn is governed by rules relating the position of a neuron's soma and dendrites to the position of the local presynaptic neurons from which it receives inputs, which are specific to the axis and direction (dorsalvs.ventral), whether the input is excitatory or inhibitory, and the laminar position of the postsynaptic neuron.