Fazalbhoy Azharuddin, Birznieks Ingvars, Macefield Vaughan G
Faculty of Medicine, Prince of Wales Clinical School, University of New South Wales, Sydney, Australia.
Exp Brain Res. 2014 Apr;232(4):1309-15. doi: 10.1007/s00221-014-3847-7. Epub 2014 Jan 31.
We recently showed that long-lasting muscle pain, induced by intramuscular infusion of hypertonic saline, evoked two patterns of cardiovascular responses across subjects: one group showed parallel increases in muscle sympathetic nerve activity (MSNA), blood pressure, and heart rate, while the other group showed parallel decreases. Given that MSNA is consistent day to day, we tested the hypothesis that individuals who show increases in MSNA during experimental muscle pain will show consistent responses over time. MSNA was recorded from the peroneal nerve, together with blood pressure and heart rate, during an intramuscular infusion of hypertonic saline causing pain for an hour in 15 subjects on two occasions, 2-27 weeks apart. Pain intensity ratings were not significantly different between the first (5.8 ± 0.4/10) and second (6.1 ± 0.2) recording sessions. While four subjects showed significant decreases in the first session (46.6 ± 9.2% of baseline) and significant increases in the second (159.6 ± 8.9%), in 11 subjects, there was consistency in the changes in MSNA over time: either a sustained decrease (55.6 ± 6.8%, n = 6) or a sustained increase (143.5 ± 6.1%, n = 5) occurred in both recording sessions. There were no differences in pain ratings between sessions for any subjects. We conclude that the changes in MSNA during long-lasting muscle pain are consistent over time in the majority of individuals, reflecting the importance of studying interindividual differences in physiology.
我们最近发现，通过肌肉内输注高渗盐水诱发的持续性肌肉疼痛，在不同受试者中引发了两种心血管反应模式：一组受试者的肌肉交感神经活动（MSNA）、血压和心率呈平行增加，而另一组则呈平行下降。鉴于MSNA在一天内是稳定的，我们检验了这样一个假设，即在实验性肌肉疼痛期间MSNA增加的个体，其反应会随时间保持一致。在15名受试者中，两次分别在间隔2至27周的时间进行肌肉内输注高渗盐水，持续一小时诱发疼痛，期间记录腓神经的MSNA，同时记录血压和心率。第一次（5.8±0.4/10）和第二次（6.1±0.2）记录期间的疼痛强度评分无显著差异。虽然有4名受试者在第一次记录时MSNA显著下降（为基线的46.6±9.2%），而在第二次记录时显著增加（159.6±8.9%），但在11名受试者中，MSNA随时间的变化具有一致性：在两次记录期间均出现持续下降（55.6±6.8%，n = 6）或持续增加（143.5±6.1%，n = 5）。所有受试者在各次记录期间的疼痛评分均无差异。我们得出结论，在大多数个体中，持续性肌肉疼痛期间MSNA的变化随时间是一致的，这反映了研究个体生理差异的重要性。
