Separate inhibitory and excitatory components underlying receptive field organization in superficial medullary dorsal horn neurons.
Separate inhibitory and excitatory components underlying receptive field organization in superficial medullary dorsal horn neurons.
复制标题
DOI：
10.1523/jneurosci.4474-11.2011
复制
发表时间：
2011-11-23
期刊：
影响因子：
--
通讯作者：
Strassman AM
中科院分区：
文献类型：
--
作者：
Kato G;Kosugi M;Mizuno M;Strassman AM
细胞外记录表明，背角神经元可以在其兴奋性感受野外具有抑制性环绕，但不能揭示兴奋性场内的抑制性输入，或显示决定净输出的潜在兴奋性和抑制性突触输入。为了研究感受野组织的基本组成部分，在体内膜片钳记录被用来比较的大小和分布的阈下，阈上，和抑制性领域，在小鼠浅延髓背角的神经元，其特征在于他们的反应，有害和无害的机械面部刺激。阈下兴奋性场通常延伸超出阈上场的边界一定距离，并且通常还表现出更广泛的刺激选择性，因为大多数伤害性特异性神经元表现出对刷的阈下反应。单独的电压钳记录的兴奋性和抑制性的输入，使用不同的保持电位显示，抑制可以引起从内以及外的兴奋性领域。在伤害性神经元，抑制往往是最大的兴奋性感受野中心，通常是更大的捏比刷，虽然捏刷的选择性不如兴奋性反应。根据目前有关背角组织的数据，我们提出兴奋性场中心的局部抑制峰值可能由局部中间神经元介导，而更广泛的周围抑制可能取决于脊髓上回路。
Extracellular recording has shown that dorsal horn neurons can have an inhibitory surround outside their excitatory receptive field, but cannot reveal inhibitory inputs within the excitatory field, or show the underlying excitatory and inhibitory synaptic inputs that determine net output. In order to study the underlying components of receptive field organization, in vivo patch clamp recording was used to compare the size and distribution of subthreshold, suprathreshold, and inhibitory fields, in neurons in the mouse superficial medullary dorsal horn that were characterized by their responses to noxious and innocuous mechanical facial stimulation. Subthreshold excitatory fields typically extended some distance beyond the borders of the suprathreshold field, and also commonly exhibited broader stimulus selectivity, in that the majority of nociceptive-specific neurons exhibited subthreshold responses to brush. Separate voltage-clamp recording of excitatory and inhibitory inputs using different holding potentials revealed that inhibition could be evoked from both within as well as outside the excitatory field. In nociceptive neurons, inhibition tended to be maximal at the excitatory receptive field center, and was usually greater for pinch than brush, although the selectivity for pinch vs brush was not as great as with excitatory responses. Based on current data on dorsal horn organization, we propose that the localized peak of inhibition at the excitatory field center could be mediated by local interneurons, while the more widespread surrounding inhibition may depend on supraspinal circuitry.