Fitzgerald M
Brain Res. 1982 Sep 23;248(1):97-107. doi: 10.1016/0006-8993(82)91151-9.
Dorsal horn cells in the lumbar spinal cord of decerebrate spinal rats were examined 7-21 days following local application of capsaicin to the sciatic nerve. Such local capsaicin treatment is known not to influence the size of the incoming A and C fibre afferent volley. The receptive field properties and primary afferent input of cells on both sides of the cord, that is ipsi and contralateral to the treated nerve, were examined. On the treated side, the percentage of cells excited by C fibres from the capsaicin treated nerve was 30% of normal and the number of cells responding to noxious heating of the cutaneous receptive field was reduced by 50%. A fibre input and low and high threshold mechanical input were normal. The receptive field size was larger in many cells innervated by the treated nerve. On the side opposite to the treated nerve, responses to noxious and non-noxious stimulation of the untreated limb were unaffected as was the input from the untreated sciatic nerve. Receptive fields were somewhat larger than normal. Effects were also observed from contralateral stimuli. Cells on both sides of the cord were found with excitatory contralateral receptive fields and excitatory responses to trains of high intensity stimulation to the contralateral sciatic nerve. In untreated animals the effect of such contralateral stimulation is inhibitory. The results show that peripheral nerve capsaicin treatment causes long lasting reduction of the C fibre input to dorsal horn cells on the treated side. However, it also results in changes in the inhibitory and excitatory receptive fields of cells on both sides of the cord.
在对去大脑脊髓大鼠的坐骨神经局部应用辣椒素7 - 21天后，对其腰脊髓背角细胞进行了检查。已知这种局部辣椒素处理不会影响传入的A纤维和C纤维传入冲动的大小。对脊髓两侧（即与处理神经同侧和对侧）细胞的感受野特性和初级传入输入进行了检查。在处理侧，由来自辣椒素处理神经的C纤维兴奋的细胞百分比为正常的30%，对皮肤感受野进行有害加热有反应的细胞数量减少了50%。A纤维输入以及低阈值和高阈值机械输入正常。许多由处理神经支配的细胞的感受野尺寸更大。在处理神经的对侧，对未处理肢体的有害和无害刺激的反应未受影响，来自未处理坐骨神经的输入也未受影响。感受野比正常情况稍大。对侧刺激也观察到了影响。在脊髓两侧都发现有细胞具有兴奋性对侧感受野，并且对向对侧坐骨神经施加的一系列高强度刺激有兴奋反应。在未处理的动物中，这种对侧刺激的作用是抑制性的。结果表明，外周神经辣椒素处理导致处理侧背角细胞的C纤维输入长期减少。然而，它也导致脊髓两侧细胞的抑制性和兴奋性感受野发生变化。
