An electrophysiological study on the mechanoreceptors in the lumbar intervertebral disc and the posterior longitudinal ligament.

实验用12只体重2.3-5.6 kg（平均体重）的成年猫进行。， 3.1公斤)。麻醉维持在戊巴比妥钠和溴化泮溴铵静脉滴注，使用人工呼吸机。L1至L7行椎板切除术。然后分离L5-L7背根，在其近端切开。然后将每个根覆盖在双极电极上。为了研究锁相环中机械敏感传入单元的感受野，用玻璃探针记录了锁相环上机械刺激所引起的传入脉冲。当感受野被识别后，用双极电极对它们进行电刺激以获得传导速度（cv），并用一组17根尼龙丝进行刺激以确定机械阈值。在腰椎前屈韧带中发现了12个机械敏感传入单位。在这12个单元中，9个位于椎体部分，其余位于…更多的位于椎间盘部分。这些装置的力学阈值为20.90 ~ 67.80 g （avr）。45.40 g)。所有这些单位都有高机械阈值（大于7.0 g）。只有一个单位的CV值为0.5-2.5 m/sec （IV组），其余11个单位的CV值为2.5-20 m/sec （III组）。感觉神经纤维按直径和CV分为I ~ IV组。分类为III组或IV组且机械阈值高（大于7.0 g）的机械敏感单位被认为是伤害性单位。另一方面，那些被归类为II或III组和低阈值（小于7.0 g）的被认为是本体感觉单位。本研究中确定的所有单元都具有较高的阈值，被归类为III或IV组。如上所述，本研究中确定的所有单元都被认为是伤害性单元。这一结果表明，腰椎前锁韧带的传入纤维主要参与注意功能，而不是本体感觉功能。尽管腰椎前屈韧带可能与腰痛的机制有关，这是对不稳定或压力的反应的结果。少

The experiments were carried out using twelve adult cats weighing 2.3-5.6 kg (avr., 3.1 kg). The anesthesia was maintained by sodium pentobarbital i.v. And pancronium bromide i.v., using an artificial ventilation machine. Laminectomy was performed on L1 to L7. Then the L5-L7 dorsal rootlets were separated and cut at their proximal ends. Each rootlet was then draped over a bipolar electrode. To investigate the receptive fields of the mechanosensitive afferent units in the PLL, afferent impulses that were evoked by the mechanical stimulation on the PLL with a glass probe were recorded. When the receptive fields were identified, they were stimulated electrically with a bipolar electrode to obtain conduction velocities (CVs) and were stimulated with a set of seventeen nylon filaments to determine the mechanical thresholds.Twelve mechanosensitive afferent units were identified in the lumbar PLL. Of these twelve units, nine were located in the vertebral body portion and the others were locat … More ed in the intervertebral disc portion. The mechanical thresholds of these units were 20.90-67.80 g (avr., 45.40 g). All of these units had high mechanical threshold (more than 7.0 g). Only one unit had a CV of 0.5-2.5 m/sec (group IV) and the remaining 11 units had CVs of 2.5-20 m/sec (group III).Sensory nerve fibers were classified into groups I to IV according to their diameter and CV. Mechanosensitive units classified as group III or IV and with a high mechanical threshold (more than 7.0 g) have been thought to act as nociceptive units. On the other hand those classified as group II or III and with a low threshold (less than 7.0 g) have been thought to act as proprioceptive units. All of the units identified in this study had a high threshold and were classified as group III or IV. As mentioned above, all of the units identified in this study were thought to be nociceptive units. This result suggests that afferent fibers from the lumbar PLL principally contribute to the noticeptive function, not to the proprioceptive function. It is though that the lumbar PLL may be involved in the mechanisms of low back pain as a result of the reaction to instability or stress. Less