Trigeminal Nerve Transection-Induced Neuroplastic Changes in the Somatosensory and Insular Cortices in a Rat Ectopic Pain Model
Trigeminal Nerve Transection-Induced Neuroplastic Changes in the Somatosensory and Insular Cortices in a Rat Ectopic Pain Model
复制标题
DOI：
10.1523/eneuro.0462-18.2019
复制
发表时间：
2019-01-01
期刊：
影响因子：
3.4
通讯作者：
Kobayashi, Masayuki
中科院分区：
文献类型：
--
作者：
Fujita, Satoshi;Yamamoto, Kiyofumi;Kobayashi, Masayuki
初级感觉皮层处理竞争性感觉输入。这些竞争性输入的消融诱导局部皮层回路的神经可塑性变化。然而，有关竞争性伤害性输入干扰引起的皮层可塑性的信息是有限的。来自上颌和下颌磨牙牙髓的伤害性信息会聚在腹侧次级躯体感觉皮层（S2）和岛状口腔区（IOR）之间的边界处;因此，S2/IOR是检查由伤害性输入干扰引起的皮层变化的合适目标，所述伤害性输入干扰常常引起神经性疼痛和异常性疼痛。我们专注于可塑性变化的S2/IOR兴奋大鼠模型进行下牙槽神经横断（IANX）。我们使用电压敏感染料（VSD）的光学成像显示，上颌磨牙牙髓刺激诱导的兴奋性传播扩大后一到两周IANX在宏观水平。在细胞水平上，基于使用双光子显微镜的Ca 2+成像，在兴奋性和抑制性神经元中，S2/IOR中的Ca 2+响应的幅度和响应神经元的数量增加。体外激光扫描光刺激（LSPS）显示，在IANX模型中，S2/IOR区的第II/III层锥体神经元和GABA能快发放神经元从第IV层接受更大的兴奋性输入，这支持了宏观和微观光学成像所获得的结果。此外，在IANX模型中，对锥体神经元的抑制性突触后输入减少，表明抑制性突触传递到兴奋性神经元的抑制。这些结果表明，IANX通过改变局部兴奋和抑制回路诱导S2/IOR的可塑性变化。
The primary sensory cortex processes competitive sensory inputs. Ablation of these competitive inputs induces neuroplastic changes in local cortical circuits. However, information concerning cortical plasticity induced by a disturbance of competitive nociceptive inputs is limited. Nociceptive information from the maxillary and mandibular molar pulps converges at the border between the ventral secondary somatosensory cortex (S2) and insular oral region (IOR); therefore, S2/IOR is a suitable target for examining the cortical changes induced by a disturbance of noxious inputs, which often causes neuropathic pain and allodynia. We focused on the plastic changes in S2/IOR excitation in a model of rats subjected to inferior alveolar nerve transection (IANX). Our optical imaging using a voltage-sensitive dye (VSD) revealed that the maxillary molar pulp stimulation-induced excitatory propagation was expanded one to two weeks after IANX at the macroscopic level. At the cellular level, based on Ca2+ imaging using two-photon microscopy, the amplitude of the Ca2+ responses and the number of responding neurons in S2/IOR increased in both excitatory and inhibitory neurons. The in vitro laser scanning photostimulation (LSPS) revealed that Layer II/III pyramidal and GABAergic fast-spiking neurons in S2/IOR received larger excitatory inputs from Layer IV in the IANX models, which supports the findings obtained by the macroscopic and microscopic optical imaging. Furthermore, the inhibitory postsynaptic inputs to the pyramidal neurons were decreased in the IANX models, suggesting suppression of inhibitory synaptic transmission onto excitatory neurons. These results suggest that IANX induces plastic changes in S2/IOR by changing the local excitatory and inhibitory circuits.