Facilitation of spinal sciatic neuron responses to hindpaw thermal stimulation after formalin injection in rat tail
Facilitation of spinal sciatic neuron responses to hindpaw thermal stimulation after formalin injection in rat tail
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DOI：
10.1007/s002210050758
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发表时间：
1999-06-01
影响因子：
2
通讯作者：
Sotgiu, ML
中科院分区：
文献类型：
--
作者：
Biella, G;Bianchi, M;Sotgiu, ML
最近的模型福尔马林注射在尾部诱导促进后爪退缩反射。在本工作中，我们试图，福尔马林注射到尾部的白化病大鼠，以确定自发活动和反应的变化，腰坐骨神经的宽动态范围神经元的热刺激的爪子在45 ℃和48 ℃（相应的阈值为有害和非有害的热刺激）。实验采用梳状排列的多个记录电极在坐骨神经投射野L4-L 6水平的脊髓腰段进行。注射后2分钟，自发活动的显着促进作用已经很明显; 5分钟时，热刺激有很强的促进作用。在45摄氏度的刺激，往往无效之前，福尔马林注射，成为强烈的兴奋。48摄氏度的刺激引起了更明显的反应。对自发和热反应的这种易化作用遵循与爪福尔马林注射后观察到的兴奋所描述的相当的时间过程，但持续时间更长，持续超过2小时。这些数据表明，福尔马林对脊髓坐骨神经元的作用后，在尾部注射的易化作用。有人建议，脊髓神经元在遥远的脊髓节段的相互作用可以解释的便利和这样的时间过程，并可以设想在长期疼痛的发展中的作用。
A recent model of formalin injection in the tail induced a facilitation of the hindpaw withdrawal reflexes. In the present work we tried, after injecting formalin into the tail of the albino rat, to determine the spontaneous activity and response changes of lumbar sciatic wide-dynamic-range neurons to thermal stimulations of the paw at 45 degrees C and 48 degrees C (the respective thresholds for noxious and non-noxious thermal stimuli). The experiments were carried out with multiple recording electrodes placed in a comb array in the lumbar segments of the spinal cord at L4-L6 level in the sciatic projection field. A significant facilitation of the spontaneous activity was already evident 2 min after injection; at 5 min there were strong facilitations to the thermal stimuli. Stimuli at 45 degrees C, often ineffective prior to the formalin injection, became strongly excitatory. Stimuli at 48 degrees C evoked more conspicuous responses. This facilitatory effect on spontaneous and thermal responses followed a rime-course comparable to that described for the excitations seen after paw formalin injection, but the duration was more prolonged, lasting more than 2 h. These data indicate a facilitatory role of the formalin effects on spinal sciatic neurons after injection in the tail. It is proposed that the mutual effects of spinal neurons in distant spinal segments could explain the facilitation and such a time-course, and that a role in the development of prolonged pain could be envisaged.