Karlsson A K, Friberg P, Lönnroth P, Sullivan L, Elam M
Spinal Injury Unit, Institute of Clinical Neuroscience, University of Göteborg, Sweden.
Brain. 1998 Sep;121 ( Pt 9):1711-9. doi: 10.1093/brain/121.9.1711.
Centrally mediated sympathetic stimulation of subjects who have suffered a spinal cord injury (SCI) does not activate the decentralized part of the body below the level of the lesion, whereas experimental data indicate an exaggerated response above the level of the lesion. SCI subjects may exhibit an autonomic dysreflexia reaction following afferent stimulation below the level of the lesion. In order to investigate the function of the sympathetic nervous system above and below the level of the lesion, regional noradrenaline spillover was measured by means of steady-state isotope dilution technique above (forearm) and below (leg) the level of the lesion at baseline, during mental stress and following bladder stimulation in nine SCI subjects (mean age 41 years; level of injury C7-T4; mean duration of injury 13.8 years). The results from the SCI subjects were also compared with those from 10 weight- and age-matched control subjects, both at rest and during mental stress. Body composition was determined by dual energy X-ray absorptiometry scanning and arm/leg blood flow by occlusion plethysmography. At baseline, total and regional noradrenaline spillover did not differ between the groups. Mental stress increased mean arterial pressure in both groups. Heart rate (76 versus 64 beats/min; P < 0.05) and arm noradrenaline spillover (2.73 versus 1.71 pmol/min/100 g; P < 0.05) increased more in spinal cord injury subjects than in control subjects, whereas total body (2826 versus 3783 pmol/min; P < 0.01) and leg noradrenaline spillover (0.23 versus 0.41 pmol/min/100 g; P < 0.05) increased only in the control group. During bladder stimulation, SCI subjects reacted with a marked increase in mean arterial pressure and leg noradrenaline spillover (from 0.06 to 0.91 pmol/min/100 g; P < 0.05) and their leg blood flow decreased. Regional and total noradrenaline clearance were similar in the two groups. In conclusion, peripheral afferent stimulation below the level of the lesion in spinal cord injury subjects gives rise to a marked noradrenaline spillover from the decentralized part of the sympathetic nervous system suggesting a remaining, but qualitatively altered, neuronal function. Centrally mediated stimulation induced an exaggerated response above the level of the lesion.
脊髓损伤（SCI）患者中枢介导的交感神经刺激不会激活损伤平面以下身体的失神经支配部分，而实验数据表明损伤平面以上会出现过度反应。SCI患者在损伤平面以下的传入刺激后可能会出现自主神经反射异常反应。为了研究损伤平面上下交感神经系统的功能，采用稳态同位素稀释技术，在9名SCI患者（平均年龄41岁；损伤平面C7-T4；平均损伤持续时间13.8年）的损伤平面以上（前臂）和以下（腿部），于基线、精神应激期间及膀胱刺激后测量局部去甲肾上腺素溢出。还将SCI患者的结果与10名体重和年龄匹配的对照受试者在静息和精神应激时的结果进行比较。通过双能X线吸收法扫描测定身体成分，通过肢体体积描记法测定手臂/腿部血流量。在基线时，两组的总去甲肾上腺素溢出和局部去甲肾上腺素溢出无差异。精神应激使两组的平均动脉压升高。脊髓损伤患者的心率（76次/分钟对64次/分钟；P<0.05）和手臂去甲肾上腺素溢出（2.73皮摩尔/分钟/100克对1.71皮摩尔/分钟/100克；P<0.05）比对照受试者升高更多，而全身（2826皮摩尔/分钟对3783皮摩尔/分钟；P<0.01）和腿部去甲肾上腺素溢出（0.23皮摩尔/分钟/100克对0.41皮摩尔/分钟/100克；P<0.05）仅在对照组中升高。在膀胱刺激期间，SCI患者的平均动脉压和腿部去甲肾上腺素溢出显著升高（从0.06皮摩尔/分钟/100克升至0.91皮摩尔/分钟/100克；P<0.05），且腿部血流量减少。两组的局部和总去甲肾上腺素清除率相似。总之，脊髓损伤患者损伤平面以下的外周传入刺激会导致交感神经系统失神经支配部分出现明显的去甲肾上腺素溢出，提示神经元功能虽有残留但性质发生了改变。中枢介导的刺激在损伤平面以上诱发了过度反应。
