Cutaneous C-fiber pain abnormalities of fibromyalgia patients are specifically related to temporal summation
Cutaneous C-fiber pain abnormalities of fibromyalgia patients are specifically related to temporal summation
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DOI：
10.1016/j.pain.2008.04.024
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发表时间：
2008-10-15
期刊：
影响因子：
7.4
通讯作者：
Price, Donald D.
中科院分区：
文献类型：
--
作者：
Staud, Roland;Bovee, Courtney E.;Price, Donald D.
Temporal summation of "second pain" (TSSP) is considered to be the result of C-fiber evoked responses of dorsal horn neurons, termed 'windup'. TSSP is dependent on stimulus frequency (>= 0.33 Hz) and is relevant for central sensitization and chronic pain. We have previously shown that compared to normal controls (NC), fibromyalgia (FM) subjects show abnormal TSSP, requiring lower stimulus intensities/frequencies to achieve similar TSSP, However, it is unknown whether abnormal TSSP in FM is influenced by peripheral sensitization of C-fiber nociceptors and/or bias in pain ratings. Thus, we evaluated 14 FM subjects and 19 NC with pain threshold tests to selective C-fiber stimulation, 30 s heat stimuli, and repetitive brief (1.5s) heat pulses at 0.33 Hz using a contact heat stimulator (CHEPS). The intensity of heat pulses was varied to achieve maximal TSSP ratings of 45 +/- 10 (numerial pain scale 0-100) in both FM and NC groups. We found that NC and FM subjects had similar pain thresholds to C-fiber stimulation and yet FM subjects required lower heat pulse temperatures to generate the same magnitudes of TSSP (p < .05). This combination of findings does not support peripheral sensitization and suggests central TSSP abnormalities in FM subjects. In a second experiment, all aspectss of individually adjusted TSSP heat pulses were kept the same except that the baseline temperature (BT) between heat pulses was surreptitiously alternated between 35 degrees C and 40 degrees C. These changes of BT resulted in significantly greater TSSP ratings of FM subjects compared to NC subjects, both at 35 degrees C and at 40 degrees C but did not change their response to the first heat pulse of a stimulus train. These findings provide strong support for alterations of central pain sensitivity and not peripheral sensitization or rating bias as responsible for TSSP difference between NC and FM subjects. (C) 2008 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
