EFFECTS OF ELECTRICAL AND MECHANICAL STIMULATION ON 2 FOCI OF SPONTANEOUS ACTIVITY WHICH DEVELOP IN PRIMARY AFFERENT NEURONS AFTER PERIPHERAL AXOTOMY
EFFECTS OF ELECTRICAL AND MECHANICAL STIMULATION ON 2 FOCI OF SPONTANEOUS ACTIVITY WHICH DEVELOP IN PRIMARY AFFERENT NEURONS AFTER PERIPHERAL AXOTOMY
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DOI：
10.1016/0304-3959(84)90820-0
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发表时间：
1984-01-01
期刊：
影响因子：
7.4
通讯作者：
BURCHIEL, KJ
中科院分区：
文献类型：
--
作者：
BURCHIEL, KJ
SD大鼠28只，在股骨中段水平切断一侧坐骨神经。术后1~21d观察动物行为学变化，1~14d取同侧L5背根和坐骨神经的微丝进行电生理记录。记录到两种类型的自发放电：一种是典型的节律性爆发式放电，可由机械刺激神经瘤驱动；另一种是低频(0.25-14赫兹)不规则活动，在切除或局部麻醉神经瘤后持续。在切除神经瘤后，也可以从坐骨神经的近端记录到后一种活动。第一种活动来自神经瘤，第二种活动起源于背根神经节(DRG)。对涉及每种放电类型的纤维的传导速度的分析表明，两者都涉及较小的有髓细丝。背根神经节的活动涉及A三角内传导速度明显较小的纤维。射程。分别在第3天和第4天记录神经瘤的自发活动和DRG的活动。持续放电在7-10天达到最大值，14天后罕见。同侧足部的自体切断术也发生在类似的时间过程中。强电刺激(100赫兹)对基线放电率的影响很小，或者延长了神经瘤活动纤维的后放电。在具有DRG起源的持续活动的纤维中，刺激产生了一种刻板的、短暂的低频后爆发，然后延长了对放电的抑制。机械刺激神经瘤可引起短暂的自发放电增加和长时间的后放电。在具有自发DRG活动的纤维中，对其起源的神经节进行最小的机械刺激会产生长时间的高频放电。切断背根节神经元的外周轴突产生自发活动，不同于正在进行的神经瘤活动，部分纤维具有潜在的伤害性(A。以及背根神经节的异常机械敏感性。电刺激这些纤维产生长时间的放电抑制。这一发现可能部分解释了外周强直性电刺激后慢性周围性疼痛患者可能经历的症状持续缓解的原因。
In 28 Sprague-Dawley rats, unilateral division of the sciatic nerve at the level of the midfemur was performed. Animals were observed for behavioral changes for 1-21 days, and electrophysiological recordings were made from microfilaments dissected from the ipsilateral [lumbar] L5 dorsal rootlets and sciatic nerve from 1-14 days postoperatively. Spontaneous discharges of 2 types were recorded: variable frequency (0-100 Hz) discharges which typically occurred in rhythmic bursts and could be driven by mechanical stimulation of the neuroma and lower frequency (0.25-14 Hz) irregular activity which persisted after either excision or local anesthesia of the neuroma. Th latter activity could also be recorded from the proximal cut end of the sciatic nerve following removal of the neuroma. The 1st type of activity was produced from the neuroma while the 2nd originated in the region of the dorsal root ganglion (DRG). Analysis of the conduction velocities of fibers involved in each type of discharge indicated that both involved smaller myelinated filaments. The DRG activity involved significantly smaller fibers with conduction velocities in the A.delta. range. Spontaneous activity was recorded at 3 and 4 days for the neuroma and DRG activity, respectively. Ongoing discharges maximized at 7-10 days and were rare by 14 days. Autotomy of the ipsilateral foot was found to occur over a similar time course. Tetanic electrical stimulation (100 Hz) produced either little change in the baseline firing rate or prolonged afterdischarges in fibers manifesting neuroma activity. In fibers with ongoing activity of DRG-origin, stimulation produced a stereotyped, brief low-frequency afterburst and then prolonged inhibition of firing. Mechanical stimulation of the neuroma produced both brief increases in spontaneous discharges and prolonged afterdischarges. In fibers with spontaneous DRG activity, minimal mechanical stimulation of their ganglion of origin produced prolonged high-frequency firing. Peripheral axotomy of DRG neurons produces spontaneous activity distinct from ongoing neuroma activity in a proportion of fibers which are potentially nociceptive (A.delta.) as well as abnormal mechanosensitivity of the DRG. Electrical stimulation of these fibers produces prolonged inhibition of the discharge. This finding may partially explain the prolonged relief of symptoms patients with chronic pain of peripheral origin may experience following peripheral tetanic electrical stimulation.