Changes in neuronal activities in the two ventral posterior medial thalamic nuclei in an experimental model of trigeminal pain in the rat by constriction of one infraorbital nerve.
Changes in neuronal activities in the two ventral posterior medial thalamic nuclei in an experimental model of trigeminal pain in the rat by constriction of one infraorbital nerve.
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DOI：
10.1080/08990220050020535
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发表时间：
2000
影响因子：
0.9
通讯作者：
B. Vos;J. Benoist;M. Gautron;G. Guilbaud
中科院分区：
文献类型：
--
作者：
B. Vos;J. Benoist;M. Gautron;G. Guilbaud
本研究分析了三叉神经病理性疼痛大鼠模型中丘脑两个腹后内侧 (VPM) 核中记录的 120 个神经元的活动。 28 只大鼠在眶下神经 (IoN) 慢性压迫性损伤 (CCI) 两周后接受了测试。这些动物对损伤的 IoN 区域以及较小程度的未损伤的 IoN 区域施加极弱的机械刺激，表现出与疼痛相关的剧烈反应。将受损神经对侧和同侧的 VPMc (n = 80) 和 VPMi (n = 40) 中记录的神经元活动分别与 10 只正常大鼠 (VPMn) VPM 中记录的 62 个神经元的活动进行比较。 CCI-IoN 大鼠 VPM 的神经元背景活动高于正常大鼠（约 4 vs 1 脉冲/秒）。在三种 VPM 中，由对侧施加于其记录部位的机械刺激驱动的神经元比例（63-70%）相当，但有效刺激方式在正常大鼠和病变大鼠之间存在显着差异。特别是，CCI-IoN 大鼠 VPM 中由触须或护毛运动驱动的神经元数量显着减少，主要是在 VPMc 中（VPMn 中 67% 的神经元具有感受野 (RF)，而 VPMc 中 12% 的神经元）。相反，VPMc 和 VPMi 中一致数量的神经元由施加到 IoN 区域的其他刺激方式驱动（VPMc 神经元为中等压力，VPMc 和 VPMi 神经元为捏或针刺）。由此引起的反应特别强烈，包括后放电。与 VPMn 神经元相反，VPMc 和 VPMi 神经元的 RF 至少包括两个触须，并且偶尔是不连续的和多峰的，包括 VPMc 单元的触须和皮肤区域。 VPM 反应性和行为的双边变化表明涉及感觉信息的中央处理，这是由 CCI-IoN 引发的。讨论了 VPM 神经元活动变化的假定机制和功能意义。
The present study analyzes the activity of 120 neurons recorded in the two ventro-postero-medial (VPM) nuclei of the thalamus in a rat model of trigeminal neuropathic pain. Twenty-eight rats were tested 2 weeks after a chronic constriction injury (CCI) of the infraorbital nerve (IoN). These animals exhibited violent pain-related reactions to extremely weak mechanical stimuli applied to the lesioned and, to a lesser extent, unlesioned IoN territories. The activities of neurons recorded in the VPMc (n = 80) and VPMi (n = 40), contralateral and ipsilateral to the injured nerve, respectively, were compared with those of 62 neurons recorded in the VPM of ten normal rats (VPMn). The neuronal background activity was higher in the VPM of CCI-IoN rats than in normal rats (about 4 vs 1 spike/s). The proportion of neurons which were driven by mechanical stimulations applied contralaterally to their recording site, was comparable in the three VPM (63-70%), but the effective stimulus modality differed significantly between the normal and the lesioned rats. In particular, the number of neurons driven by vibrissa or guard hair movements dramatically decreased in the VPM of CCI-IoN rats, mainly in the VPMc (67% of neurons with a receptive field (RF) in the VPMn vs 12% in the VPMc). Inversely, a consistent number of neurons in both the VPMc and VPMi were driven by other stimulus modalities applied to the IoN territory (moderate pressure for VPMc neurons, pinch or pinprick for both VPMc and VPMi neurons). The responses so induced were especially intense and included afterdischarges. In contrast to the VPMn neurons, the RFs of both the VPMc and VPMi neurons included two vibrissae at least, and were occasionally discontinuous and multimodal, including both vibrissae and cutaneous areas for VPMc units. The bilateral changes in VPM responsiveness and in behavior suggest the involvement of central processing of sensory information, which are set off by the CCI-IoN. The putative mechanisms and functional implication of the changes in the VPM neuronal activities are discussed.