Properties of mouse spinal lamina I GABAergic interneurons
Properties of mouse spinal lamina I GABAergic interneurons
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DOI：
10.1152/jn.00184.2005
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发表时间：
2005-11-01
影响因子：
2.5
通讯作者：
Hochman, S
中科院分区：
文献类型：
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作者：
Dougherty, KJ;Sawchuk, MA;Hochman, S
板层I是一个感觉中继区，包含投射细胞和参与热和伤害性信号传导的局部中间神经元。这些神经元在形态、感觉反应方式和放电特征上不同。我们研究了表达增强型绿色荧光蛋白（EGFP）的小鼠I层GABA能神经元的内在特性。GABA能神经元的身份通过GABA免疫标记和EGFP荧光之间的高度对应性来证实。这些EGFP（+）/GABA（+）细胞的形态为多极（65%）、梭形（31%）和锥体（4%）。在全细胞记录中，细胞发射单个尖峰（44%），紧张性（35%），或响应于当前步骤的初始爆发（21%），代表报告的板层I发射特性的子集。紧张性和初始爆发细胞的膜特性是难以区分的，这些神经元可能代表一个功能群体，因为在单个神经元中，它们的放电模式可以相互转换。单个棘细胞的兴奋性较低，膜电阻率和较高的基强度。大多数梭形细胞（64%）的紧张性放电，而大多数多极细胞（56%）发射单棘波。总之，I层抑制性中间神经元在功能上可分为至少两个主要的群体，这两个群体可能都起到限制兴奋性传递的作用。
Lamina I is a sensory relay region containing projection cells and local interneurons involved in thermal and nociceptive signaling. These neurons differ in morphology, sensory response modality, and firing characteristics. We examined intrinsic properties of mouse lamina I GABAergic neurons expressing enhanced green fluorescent protein (EGFP). GABAergic neuron identity was confirmed by a high correspondence between GABA immunolabeling and EGFP fluorescence. Morphologies of these EGFP(+)/GABA(+) cells were multipolar (65%), fusiform (31%), and pyramidal (4%). In whole cell recordings, cells fired a single spike (44%), tonically (35%), or an initial burst (21%) in response to current steps, representing a subset of reported lamina I firing properties. Membrane properties of tonic and initial burst cells were indistinguishable and these neurons may represent one functional population because, in individual neurons, their firing patterns could interconvert. Single spike cells were less excitable with lower membrane resistivity and higher rheobase. Most fusiform cells (64%) fired tonically while most multipolar cells (56%) fired single spikes. In summary, lamina I inhibitory interneurons are functionally divisible into at least two major groups both of which presumably function to limit excitatory transmission.