Axon-to-axon transmission in tullidora (buckthorn) neuropathy
Axon-to-axon transmission in tullidora (buckthorn) neuropathy
复制标题
沙棘神经病中的轴突间传递
DOI：
10.1016/0014-4886(84)90202-4
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发表时间：
1984
影响因子：
5.3
通讯作者：
E. Muñoz‐Martinez
中科院分区：
文献类型：
--
作者：
A. Hernández;E. Muñoz‐Martinez
口服含有一种确定的神经毒素的tullidora（Karwinskia humboldtiana）果实的乙醚提取物，在潜伏期4至7周后，可使猫产生松弛性后肢麻痹。急性实验是在麻痹明显之后进行的。尽可能靠近脊髓切断腰骶段的脊神经根，并将其分成几根细丝。刺激远端的横切诱发动作电位在其他丝（轴突-轴突传输或串扰）的一些丝至少8毫秒的潜伏期后。串扰反应经常包括多次放电。轴突到轴突的传输只在运动轴突之间观察到，当后肢神经离脊髓10 ~ 15 cm处被切断时，轴突到轴突的传输消失。双脉冲施加到灯丝在不同的时间间隔，脉冲强度进行调整，使调节脉冲是阈下引起串扰，但测试脉冲经常引起它（时间促进）。在三个充分研究的纤维的促进延长到50至80毫秒。在某些情况下，没有串扰引起在一个给定的细丝个别刺激的其他两个细丝，但同时刺激相同的细丝引起串扰（空间促进）。在这些轴突中自发地发生一系列周期性的活动爆发，对其他轴突的单次刺激进行多次放电。在低温（约30°C）下，刺激可以触发基本上类似的一系列爆发。单运动神经元胞内刺激短暂的去极化脉冲。由刺激引起的动作电位在几毫秒后由在外周产生的次级放电串（“回射”）跟随。
Oral administration of ether extracts of the tullidora (Karwinskia humboldtiana) fruit, which contains an identified neurotoxin, produced flaccid hind limb paralysis in cats after a latency of 4 to 7 weeks. Acute experiments were conducted after the paralysis was evident. Spinal roots of lumbar and sacral segments were transected as close as possible to the spinal cord and divided into several filaments. Stimulation of some filaments distal to the transection evoked action potentials in other filaments (axon-to-axon transmission or cross talk) after a latency of at least 8 ms. Cross-talk responses frequently consisted of multiple discharges. Axon-to-axon transmission was seen only between motor axons and disappeared when hind limb nerves were transected 10 to 15 cm from the spinal cord. Twin pulses were applied to a filament at various intervals; the pulse intensity was adjusted so that the conditioning pulse was subthreshold to elicit cross talk, but the test pulse frequently elicited it (temporal facilitation). In three fully studied fibers the facilitation was prolonged to 50 to 80 ms. In some cases, no cross talk was evoked in a given filament by individual stimulation of two other filaments, but simultaneous stimulation of the same filaments did evoke cross talk (spatial facilitation). Series of periodic bursts of activity spontaneously occurred in those axons responding with multiple discharges to single stimulation of other axons. At low temperatures (about 30°C) the stimulus could trigger essentially similar series of bursts. Single motoneurons were intracellularly stimulated by brief depolarizing pulses. The action potential elicited by the stimulus was followed after several msec by a secondary train of discharges generated at the periphery (“back firing”).