Shyu B C, Danielsen N, Andersson S A, Dahlin L B
Department of Physiology, University of Gothenburg, Sweden.
Acta Physiol Scand. 1990 Oct;140(2):237-43. doi: 10.1111/j.1748-1716.1990.tb08995.x.
Non-myelinated C-fibre responses during sympathetic trunk stimulation were studied in rabbit common peroneal nerve 2 weeks after the nerve had been subjected to compression at 400 mmHg for 30 min. Our previous studies have demonstrated that during sympathetic trunk stimulation the compound action potential of uninjured somatic C-fibres is characterized by a reduced amplitude and an increased latency. In the present study, nerve compression changed the C-fibre response to sympathetic stimulation. Three out of eight nerves reacted to nerve compression by increased C-fibre compound action potential amplitude in response to sympathetic stimulation. In three other rabbits with compressed nerves the C-fibre action potential amplitude was unchanged, and in the remaining two rabbits the action potential amplitude was decreased during sympathetic stimulation. The action potential latency increased in all tested compressed C-fibres. The phenomenon of increased C-fibre amplitude during sympathetic activation has not been observed in uninjured nerves. As in uninjured nerves, noradrenaline infusion produced an increased C-fibre action potential amplitude and latency in six animals. Sympathetic stimulation did not affect the A-fibre response. These results indicate that sympathetic activity influences the conduction properties in C-fibres of somatic origin and that the response can be changed after a nerve injury. The findings may be of importance for the understanding of pain aggravation in different types of nerve injuries during increased sympathetic activity.
在兔腓总神经经受400 mmHg压力30分钟的压迫后2周，研究了交感干刺激期间无髓鞘C纤维的反应。我们之前的研究表明，在交感干刺激期间，未受损躯体C纤维的复合动作电位表现为幅度降低和潜伏期延长。在本研究中，神经压迫改变了C纤维对交感刺激的反应。8条神经中有3条对神经压迫的反应是，交感刺激引起C纤维复合动作电位幅度增加。在另外3只神经受压的兔子中，C纤维动作电位幅度未改变，在其余2只兔子中，交感刺激期间动作电位幅度降低。所有测试的受压C纤维的动作电位潜伏期均增加。在未受损神经中未观察到交感激活期间C纤维幅度增加的现象。与未受损神经一样，在6只动物中，输注去甲肾上腺素使C纤维动作电位幅度和潜伏期增加。交感刺激不影响A纤维反应。这些结果表明，交感神经活动影响躯体起源的C纤维的传导特性，并且在神经损伤后反应可能会改变。这些发现可能对于理解交感神经活动增加期间不同类型神经损伤中疼痛加剧具有重要意义。
