Dorsal column-thalamic pathway is involved in thalamic hyperexcitability following peripheral nerve injury: a lesion study in rats with experimental mononeuropathy
Dorsal column-thalamic pathway is involved in thalamic hyperexcitability following peripheral nerve injury: a lesion study in rats with experimental mononeuropathy
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DOI：
10.1016/s0304-3959(99)00279-1
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发表时间：
2000-03
期刊：
影响因子：
7.4
通讯作者：
K. Miki;K. Iwata;Y. Tsuboi;T. Morimoto;E. Kondo;Yi Dai;K. Ren;K. Noguchi
中科院分区：
文献类型：
--
作者：
K. Miki;K. Iwata;Y. Tsuboi;T. Morimoto;E. Kondo;Yi Dai;K. Ren;K. Noguchi
在单侧坐骨神经慢性挤压伤(CCI)大鼠(n=20)、假手术大鼠(n=24)和幼年大鼠(n=24)的丘脑腹后外侧核(VPL)共记录到68个神经元，并研究了损毁背柱通路[DC损毁或DC+薄束核损毁]对VPL核神经元活动的影响。在CCI对侧VPL核(接受损伤神经输入)，低阈值机械感受性(LTM)和宽动态范围(WDR)神经元对电刺激坐骨神经的反应潜伏期显著长于接受假手术侧输入的对侧VPL核(P<；0.05)。而假手术侧和CCI侧LTM和WDR神经元对DC刺激的反应潜伏期差异无统计学意义(P>；0.05)。背景与假手术侧和幼年动物相比，CCI侧VPL核WDR神经元的活动显著高于假手术侧VPL核的神经元。在所有动物中，损毁DC和DC+薄束核后，LTM和WDR神经元对机械刺激感受野的反应显著降低。然而，只有CCI大鼠的WDR神经元对伤害性刺激的反应被DC和DC+薄束核损毁所选择性地降低(P<；0.05)。损毁DC和DC+薄束核后，CCI侧VPL核WDR神经元伤害性刺激反应的下降幅度大于假手术侧VPL核和幼稚动物。这些结果表明，损毁DC和DC+薄束核对VPL核WDR神经元从神经损伤部位传入的伤害性反应具有选择性和更强的影响。这些结果提示，丘脑薄束核通路向周围神经损伤后的VPL核传递或调制伤害性信息，导致VPL核对伤害性刺激的反应增强，从而促进机械性痛敏的发展。
A total of 68 neurons were recorded from the ventro-postero-lateral nucleus of thalamus (VPL) in rats with a unilateral chronic constriction injury (CCI) of the sciatic nerve (n= 20), sham operation (n= 24) and naive rats (n= 24), and effects of the lesion of dorsal column (DC) pathway [DC lesion or DC+ gracile nucleus lesions] on VPL nucleus neuronal activities were studied. In the VPL nucleus contralateral to the CCI (receiving input from the injured nerve), response latencies of low threshold mechanoreceptive (LTM) and wide dynamic range (WDR) neurons to electrical stimulation of the sciatic nerve were significantly longer than that in the contralateral VPL nucleus receiving input from the sham-operated side (P< 0.05). In contrast, response latencies of LTM and WDR neurons to DC stimulation were not different between the sham operated and CCI sides (P> 0.05). Background activity of WDR neurons was significantly higher in the VPL nucleus contralateral to the CCI side when compared to neurons in the VPL nucleus contralateral to the sham operated side and in naive animals. Responses of LTM and WDR neurons to innocuous mechanical stimulation of the receptive fields were significantly decreased after DC and DC+ gracile nucleus lesions in all animals. However, the responses of WDR neurons to noxious stimuli were selectively reduced only in rats with CCI by DC and DC+ gracile nucleus lesions (P< 0.05). The decrease in noxious stimulus-evoked responses of WDR neurons in the VPL nucleus contralateral to the CCI side after DC and DC+ gracile nucleus lesions was greater than that in the VPL nucleus contralateral to the sham operated side and naive animals. These results indicated that DC and DC+ gracile nucleus lesions produced selective and stronger effect on noxious responses of VPL nucleus WDR neurons receiving input from the site of nerve injury. The findings suggest that the gracile nucleus-thalamic pathway conveys, or modulates, nociceptive information to the VPL nucleus following peripheral nerve injury, resulting in an increase in VPL nucleus response to noxious stimuli that contributes to the development of mechanical hyperalgesia.