Laboratory for Experimental Pain Research, Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, DK-9220, Denmark.
Acta Physiol (Oxf). 2009 Aug;196(4):411-7. doi: 10.1111/j.1748-1716.2009.01960.x. Epub 2009 Feb 4.
Myofascial trigger points (MTrPs) are a major cause of musculoskeletal pain. It has been reported that stimulation of a latent MTrP increases motor activity and facilitates muscle pain via activation of the sympathetic nervous system. However, the magnitude of the sympathetic vasoconstrictor response following stimulation of MTrP has not been studied in healthy volunteers. The aims of this study were to (1) evaluate the magnitude of the vasoconstrictor response following a nociceptive stimulation (intramuscular glutamate) of MTrPs and a breath-hold manoeuvre (activation of sympathetic outflow) and (2) assess whether the vasoconstrictor response can be further modulated by combining a nociceptive stimulation of MTrPs and breath-hold.
Fourteen healthy subjects were recruited in this study. This study consisted of four sessions (normal breath group as control, breath-hold group, glutamate MTrP injection group and glutamate MTrP injection + breath-hold group). Skin blood flow and skin temperature in both forearms were measured with laser Doppler flowmetry and infrared thermography, respectively, in each session (before the treatment, during the treatment and after the treatment).
Glutamate injection into MTrPs decreased skin temperature and blood flow in the peripheral area. The magnitudes of the reduction were comparable to those induced by the breath-hold manoeuvre, which has been used to induce sympathetic vasoconstrictor response.
The combination of glutamate injection into latent MTrPs together with the breath-hold manoeuvre did not result in further decrease in skin temperature and blood flow, indicating that sympathetic vasoconstrictor activity is fully activated by nociceptive stimulation of MTrPs.
肌筋膜触发点（MTrPs）是肌肉骨骼疼痛的主要原因。据报道，潜伏的 MTrP 受到刺激会增加运动活动，并通过激活交感神经系统促进肌肉疼痛。然而，在健康志愿者中，尚未研究 MTrP 刺激后交感神经血管收缩反应的幅度。本研究的目的是：（1）评估 MTrPs 疼痛刺激（肌肉内谷氨酸）和屏气动作（激活交感传出）后血管收缩反应的幅度；（2）评估是否可以通过结合 MTrPs 的疼痛刺激和屏气进一步调节血管收缩反应。
本研究招募了 14 名健康受试者。该研究包括四个阶段（正常呼吸组作为对照，屏气组，谷氨酸 MTrP 注射组和谷氨酸 MTrP 注射+屏气组）。在每个阶段（治疗前、治疗期间和治疗后），使用激光多普勒血流仪和红外热像仪分别测量双侧前臂的皮肤血流和皮肤温度。
谷氨酸注射到 MTrPs 会降低外周区域的皮肤温度和血流。减少的幅度与屏气动作引起的幅度相当，屏气动作已被用于诱导交感神经血管收缩反应。
将潜伏的 MTrP 内的谷氨酸注射与屏气动作相结合，并没有导致皮肤温度和血流进一步降低，表明 MTrP 的疼痛刺激充分激活了交感神经血管收缩活性。
