van Selms M K A, Wang K, Lobbezoo F, Svensson P, Arendt-Nielsen L, Naeije M
Department of Oral Function, Academic Centre for Dentistry Amsterdam, Louwesweg 1, 1066 EA Amsterdam, The Netherlands.
Clin Neurophysiol. 2005 Jun;116(6):1415-23. doi: 10.1016/j.clinph.2005.02.017. Epub 2005 Apr 7.
To examine the effects of experimentally evoked masticatory muscle fatigue, without and with experimental muscle pain, on the short-latency jaw-stretch reflex, using a randomised crossover design.
Reflexes were evoked in both the masseter and temporalis muscles in 15 men and 13 women. The study was performed in two blocks, both containing 3 experimental conditions (before, directly after, and 15 min after provocation). Provocation consisted of a fatiguing chewing test, followed by an intramuscular injection of either isotonic saline (IS; non-painful) or hypertonic saline (HS; painful).
No significant effects of the experimental condition 'fatigue+IS' were found for any of the reflex outcome variables. For each muscle, the 'fatigue+HS' condition yielded significantly higher normalized reflex amplitudes than the other conditions. Several muscles displayed gender differences regarding both onset latency and normalized reflex amplitude.
Experimentally evoked mild-to-moderate muscle fatigue does not modulate the human jaw-stretch reflex. On the other hand, experimental muscle pain, evoked after the performance of a fatiguing chewing test, does yield a facilitation of this reflex. The gender differences found in both onset latency and peak-to-peak amplitude stress the need to take gender into consideration in future jaw reflex studies.
The sensitivity of the human jaw-stretch reflex can be modulated by HS-induced muscle pain; not by muscle fatigue that is provoked by intense chewing.
采用随机交叉设计，研究实验诱发的咀嚼肌疲劳（有无实验性肌肉疼痛）对短潜伏期下颌牵张反射的影响。
对15名男性和13名女性的咬肌和颞肌诱发反射。研究分两个阶段进行，每个阶段都包含3种实验条件（激发前、激发后即刻、激发后15分钟）。激发包括疲劳咀嚼试验，随后肌肉注射等渗盐水（IS；无痛）或高渗盐水（HS；疼痛）。
对于任何反射结果变量，“疲劳+IS”实验条件均未产生显著影响。对于每块肌肉，“疲劳+HS”条件下的标准化反射幅度均显著高于其他条件。几块肌肉在起始潜伏期和标准化反射幅度方面均表现出性别差异。
实验诱发的轻至中度肌肉疲劳不会调节人类下颌牵张反射。另一方面，在疲劳咀嚼试验后诱发的实验性肌肉疼痛确实会促进这种反射。在起始潜伏期和峰峰值幅度方面发现的性别差异强调了在未来下颌反射研究中考虑性别的必要性。
人类下颌牵张反射的敏感性可由HS诱导的肌肉疼痛调节；而非由强烈咀嚼诱发的肌肉疲劳调节。
