Gao X X, Ren B, Linderoth B, Meyerson B A
Karolinska Institute Center for Pain Research, Karolinska Hospital, Stockholm, Sweden.
Neuroscience. 1996 Nov;75(2):463-70. doi: 10.1016/0306-4522(96)00288-6.
Autotomy in experimental animals following peripheral nerve section has been interpreted as a sign of pain corresponding to the chronic pain observed in patients with extensive nerve lesions. Such pain may be alleviated by spinal cord stimulation. In the present study, the effect of such stimulation, via chronically implanted electrodes, on autotomy behavior following sciatic nerve section was assessed in the rat. The stimulation was applied for 30 min daily during a 10-day period. There were four groups of animals, 16 in each, half of them females. Stimulating electrodes were implanted in all and one group served as control, receiving sham stimulation. In one group, the stimulation was started when autotomy was observed, one received stimulation from the day of nerve section, and in one it was begun three days before section. The onset of autotomy was significantly delayed in the latter two groups. When stimulation was applied as "treatment", autotomy ceased but reappeared after the 10-day stimulation period. The incidence and severity of autotomy was markedly delayed and reduced when the stimulation had been applied just after the nerve section or before. In the latter groups, the diminished degree of autotomy persisted for the entire observation period, lasting 60 days after the stimulation was stopped. It seems that spinal cord stimulation, albeit applied only once daily and during a limited time period, can protect the spinal cord from developing the state of hyperexcitability believed to be the major cause of autotomy behavior. Peripheral mechanisms may also play a role by the antidromic activity evoked by the stimulation in the sectioned peripheral nerve. This study shows that spinal cord stimulation, which is a commonly employed method for treating chronic neurogenic pain, may have long-lasting effects on plasticity changes in the spinal cord following peripheral nerve injury, even when the stimulation is applied for short periods of time.
实验动物在周围神经切断后出现的自残行为被解读为与广泛神经损伤患者中观察到的慢性疼痛相对应的疼痛迹象。这种疼痛可通过脊髓刺激得到缓解。在本研究中，评估了通过长期植入电极进行的这种刺激对大鼠坐骨神经切断后自残行为的影响。在为期10天的时间里，每天施加刺激30分钟。共有四组动物，每组16只，其中一半为雌性。所有动物均植入刺激电极，一组作为对照组，接受假刺激。在一组中，当观察到自残行为时开始刺激，一组从神经切断当天开始接受刺激，另一组在切断前三天开始刺激。后两组的自残行为开始时间显著延迟。当将刺激作为“治疗”应用时，自残行为停止，但在10天刺激期后又重新出现。当在神经切断后或之前立即应用刺激时，自残行为的发生率和严重程度明显延迟并降低。在后两组中，自残行为减轻的程度在整个观察期内持续存在，在刺激停止后持续60天。似乎脊髓刺激，尽管每天仅应用一次且在有限的时间段内，但可以保护脊髓不发展为被认为是自残行为主要原因的过度兴奋状态。外周机制也可能通过刺激在切断的外周神经中诱发的逆向活动发挥作用。本研究表明，脊髓刺激作为治疗慢性神经源性疼痛的常用方法，即使在短时间内应用，也可能对周围神经损伤后脊髓的可塑性变化产生长期影响。
