家兔脊髓部分切割对脊髓背半部下行抑制作用的影响

预先刺激在T_(10)～T_(12)水平做纵向分离并横切的家兔脊髓背半部离心瑞,可明显抑制束旁核神经元的痛敏放电。在上述切面尾端5～7mm处横切双侧背柱,未发现刺放脊髓背侧部引起的下行性抑制效应有明显改变;再次在尾侧约3～5mm处横切脊髓背半部(包括双侧背外侧束),则上述下行性抑制效应不再出现。结果表明:刺激家兔脊髓背半部离心端所产生的下行性抑制作用,主要是通过背外侧索中的下行纤维实现的,而背柱系统与此效应关系不大。

Effects of Partial Transection of the Spinal Cord on the Antinociceptive Action Produced by Stimulation of the Dorsal Half of Spinal Cord in Rabbits

In the present experiments we have shown that the descending inhibitory effects elicited by the strong electrical stimulation of the peroneal nerve can not be eliminated by transection of the dorsal columns at T11-T12 level, but they can be abolished by an additional transection of the dorsal half of spinal cord at T12 -L1 level including the bilateral dorsolateral funiculi (DLF). These results suggest that the antinociceptive action produced by stimulation of the centrifugal stump of isolated dorsal half of spinal cord is mediated through the descending fibers in DLF and has little, if any, to do with the dorsal column.