Hyperexcitable C nociceptors in fibromyalgia
Article first published online: 12 FEB 2014
© 2014 Child Neurology Society/American Neurological Association
Annals of Neurology
Volume 75, Issue 2, pages 196–208, February 2014
How to Cite
Serra, J., Collado, A., Solà, R., Antonelli, F., Torres, X., Salgueiro, M., Quiles, C. and Bostock, H. (2014), Hyperexcitable C nociceptors in fibromyalgia. Ann Neurol., 75: 196–208. doi: 10.1002/ana.24065
- Issue published online: 19 MAR 2014
- Article first published online: 12 FEB 2014
- Accepted manuscript online: 16 NOV 2013 05:55AM EST
- Manuscript Accepted: 8 NOV 2013
- Manuscript Revised: 5 NOV 2013
- Manuscript Received: 20 AUG 2013
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.
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.
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.
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