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Hyperexcitable C nociceptors in fibromyalgia
Author(s) -
Serra Jordi,
Collado Antonio,
Solà Romà,
Antonelli Francesca,
Torres Xavier,
Salgueiro Monika,
Quiles Cristina,
Bostock Hugh
Publication year - 2014
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.24065
Subject(s) - nociceptor , fibromyalgia , medicine , nociception , mechanosensitive channels , anesthesia , peripheral neuropathy , endocrinology , receptor , ion channel , diabetes mellitus
Objective To test the hypothesis that peripheral C nociceptor function may be abnormal in fibromyalgia and that C nociceptor dysfunction may contribute to the symptoms reported by these patients. Methods Microneurography was used to record C nociceptors of 30 female patients meeting criteria for fibromyalgia and compared with recordings from 17 female patients with small‐fiber neuropathy and 9 female controls. Results We obtained stable recordings of 186 C nociceptors in the fibromyalgia group, 114 from small‐fiber neuropathy patients, and 66 from controls. The mechanosensitive nociceptors in the fibromyalgia patients behaved normally, but the silent nociceptors in 76.6% of fibromyalgia patients exhibited abnormalities. Spontaneous activity was detected in 31% of silent nociceptors in fibromyalgia, 34% in small‐fiber neuropathy, and 2.2% in controls. Sensitization to mechanical stimulation was found in 24.2% of silent nociceptors in fibromyalgia, 22.7% in small‐fiber neuropathy, and 3.7% in controls. Abnormally high slowing of conduction velocity when first stimulated at 0.25Hz was more common in fibromyalgia. Interpretation We show for the first time that the majority of fibromyalgia patients have abnormal C nociceptors. Many silent nociceptors exhibit hyperexcitability resembling that in small‐fiber neuropathy, but high activity‐dependent slowing of conduction velocity is more common in fibromyalgia patients, and may constitute a distinguishing feature. We infer that abnormal peripheral C nociceptor ongoing activity and increased mechanical sensitivity could contribute to the pain and tenderness suffered by patients with fibromyalgia. ANN NEUROL 2014;75:196–208