Aδ and not C fibers mediate thermal hyperalgesia to short laser stimuli after burn injury in man. Issue 11 (November 2018)

• Record Type: Journal Article
• Authors: Slimani, Hocine; Plaghki, Leon; Valenti, Paola; Werner, Mads U.; Kehlet, Henrik; Kupers, Ron
• Is Part Of: Pain. Volume 159:Issue 11(2018)
• Publication Date: 2018-11
• Subjects: Inflammation -- CO2 laser -- Nociception -- Thermal hyperalgesia -- Pain -- Burn injury; Pain -- Periodicals; Douleur -- Périodiques; Anesthésie -- Périodiques; Pain; Electronic journals; Periodicals; Electronic journals; 616.0472
• DOI: 10.1097/j.pain.0000000000001339
• Languages: English
• ISSNs: 0304-3959

Abstract

Abstract : Abstract: It remains unclear which nerve fibers are responsible for mediating hyperalgesia after skin injury. Here, we examined the role of Aδ and C fibers in inflammatory hyperalgesia after a first-degree burn injury. A CO2 laser delivered ultrafast short constant-temperature heat pulses to the upper part of the lower leg to stimulate selectively the relatively fast-conducting thinly myelinated Aδ and the slowly conducting unmyelinated C fibers. Participants were asked to respond as fast as possible whenever they detected a thermal stimulus. Thresholds and reaction times to selective Aδ and C fiber activations were measured in the conditioned and the surrounding intact skin, at pre-injury, and 1 hour and 24 hours after injury. First-degree burn injury caused a significant decrease in Aδ fiber detection thresholds and a significant increase in the proportion of Aδ-fiber-mediated responses in the inflamed area 24 hours, but not 1 hour, after burn injury. No changes in heat perception were observed in the intact skin surrounding the injury. No group differences in C-fiber-mediated sensations were observed. Our findings indicate that quickly adapting Aδ fibers but not quickly adapting C fibers are sensitized when activated by short and ultrafast heat stimuli after skin burn injury. Our results further show that this change occurs between 1 hour and 24 hours after injury and that it does not extend to the skin surrounding the injury. Abstract : Supplemental Digital Content is Available in the Text.Thermal hyperalgesia following a first-degree burn injury in humans causes a sensitization of the thinly myelinated A∂ fibers, but not of the unmyelinated C fibers.