Gopalkrishnan P, Sluka K A
Physical Therapy Graduate Program, College of Medicine, University of Iowa, Iowa City 52242, USA.
Arch Phys Med Rehabil. 2000 Jul;81(7):984-90. doi: 10.1053/apmr.2000.5576.
To examine the effect of varying frequency, intensity, and pulse duration of transcutaneous electrical nerve stimulation (TENS) on primary hyperalgesia (increased response to a noxious stimuli) to heat and mechanical stimuli induced by carrageenan paw inflammation in rats.
Inflammation was induced by injection of 3% carrageenan into the hindpaw. Two frequencies (high, 100 Hz; low, 4 Hz), 2 intensities (high, motor; low, sensory), and 2 pulse durations (100 microsec, 250 microsec) were applied for 20 minutes to the inflamed paw. The paw withdrawal latency (PWL) to radiant heat, threshold to mechanical stimuli, and spontaneous pain-related behaviors were measured before and 4 hours after induction of inflammation, after TENS, and at 8, 12, and 24 hours after inflammation. A 3-factor (frequency, intensity, pulse duration) repeated-measures (time) design was used to analyze the changes in PWL. Mechanical threshold and spontaneous pain-related behaviors were compared for frequency, intensity, and pulse duration with a Kruskal-Wallis analysis of variance.
For changes in PWL to heat, there was an effect for time (p = .0001) and frequency (p =.0001), but not for intensity (p = .45) or pulse duration (p = .21). For changes in mechanical threshold, there was also an effect for frequency (p = .007), but not for intensity (p = .055) or pulse duration (p = .058), after treatment with TENS. High-frequency TENS significantly reduced the primary hyperalgesia to heat and mechanical stimuli when compared with controls receiving no TENS or treatment with low-frequency TENS. High-frequency motor TENS also reduced spontaneous pain-related behaviors for 1 day after treatment.
High-frequency TENS reduces primary hyperalgesia to heat and mechanical stimuli for up to 1 day after treatment. In contrast, low-frequency TENS is ineffective in reducing primary hyperalgesia. Varying intensity or pulse duration had no effect on the degree of antihyperalgesia produced by high-frequency TENS.
研究经皮电刺激神经疗法（TENS）不同的频率、强度和脉冲持续时间对大鼠角叉菜胶足爪炎症诱导的热和机械刺激原发性痛觉过敏（对伤害性刺激反应增强）的影响。
通过向大鼠后爪注射3%角叉菜胶诱导炎症。将两种频率（高，100赫兹；低，4赫兹）、两种强度（高，运动强度；低，感觉强度）和两种脉冲持续时间（100微秒、250微秒）应用于发炎的爪子20分钟。在炎症诱导前、诱导后4小时、TENS治疗后以及炎症后8、12和24小时测量爪子对辐射热的缩爪潜伏期（PWL）、对机械刺激的阈值以及与自发疼痛相关的行为。采用三因素（频率、强度、脉冲持续时间）重复测量（时间）设计来分析PWL的变化。采用Kruskal-Wallis方差分析比较频率、强度和脉冲持续时间的机械阈值以及与自发疼痛相关的行为。
对于热刺激引起的PWL变化，时间（p = 0.0001）和频率（p = 0.0001）有影响，但强度（p = 0.45）或脉冲持续时间（p = 0.21）无影响。对于机械阈值的变化，TENS治疗后频率（p = 0.007）有影响，但强度（p = 0.055）或脉冲持续时间（p = 0.058）无影响。与未接受TENS或接受低频TENS治疗的对照组相比，高频TENS显著减轻了对热和机械刺激的原发性痛觉过敏。高频运动TENS在治疗后1天内也减少了与自发疼痛相关的行为。
高频TENS在治疗后长达1天的时间内可减轻对热和机械刺激的原发性痛觉过敏。相比之下，低频TENS在减轻原发性痛觉过敏方面无效。改变强度或脉冲持续时间对高频TENS产生的抗痛觉过敏程度没有影响。
