刺激大鼠大脑脚影响脊髓伤害感受性传递的下行途径

DESCENDING PATHWAYS MEDIAING THE EFFECT OFSTIMULATING CEREBRAL PEDUNCLE ON THE SPINAL NOCICEPTIVE TRANSMISSION IN THE RAT

在麻醉大鼠用部分切割脊髓的方法分析了刺激大脑脚（ＣＰ）影响脊髓背角伤害感受性神经元的下行途径。刺激ＣＰ对背角神经元伤害感受性反应（Ｃ－反应）的影响以抑制为主，部分（３０．７％）神经元在抑制作用产生之前先被兴奋。抑制作用主要是通过背索（ＤＦ）或背外侧索（ＤＬＦ）实现的，然而在多数神经元是两者共同作用的结果，其中ＤＬＦ的作用似乎更为重要。兴奋作用则是通过ＤＦ实现的。由于大鼠的皮质脊髓束（ＣＳＴ）位于ＤＦ中，以上结果提示大脑皮层不仅可直接通过ＣＳＴ，而且可经某些脊髓上结构中继后由ＤＬＦ下行调控脊髓的伤害感受性传递。

The descending pathways for the effects of stimulation of cerebtal peduncle(CP)on the nocicbptive neurons of spinal cord dorsal horn were analyzed by subtotal spinalcord lessions in anesthetized rats.Inhibition was the predominant effect of CP stimulation on the C-fiber elicit6d nociceptive responses of dorsal horn neurons,in 30.7% ofsuch neurons,the inhibition was preceded by some initial excitation.In mad neuronsthe inhibitory effect was mediated by both dorsal funiculus(DF)and dorsolateral funiculus(DLF),that of DF usually predominated.It seemed that DLF Played a moreimportant role than DF.However,the excitatory effect was mediated by DF alone.Since in the rat the corticospinal tract (CST) is situated in the DF,the results suggestthat cerebral cortex can modulate spinal nociceptive transmission not only by the CST,but also through a relay in some supraspinal structure(s)sending descending fibers intothe DLF.I