Mechanically induced axon reflex and hyperalgesia in human UV-B burn are reduced by systemic lidocaine.
The mechanisms for the induction of primary mechanical hyperalgesia are unclear. We analyzed the neurogenic axon reflex erythema (flare) following phasic mechanical stimulation in normal and in UV-B irradiated skin. In a cross-over double blind design (n = 10), low dose of systemic lidocaine suppressed mechanical hyperalgesia in sunburned skin and in the mechanically induced flare. Phasic mechanical stimulation, even at painful intensities, did not evoke a flare reaction in normal skin. However, stimulation within the UV-B burn dose-dependently provoked an immediate flare reaction. Systemic lidocaine suppressed the mechanically induced flare as well as the mechanical hyperalgesia in sunburned skin, while leaving the impact-induced ratings in normal skin unchanged. Systemic lidocaine reduced these effects of sensitization, but did not reduce ratings in normal skin. As mechanically insensitive ("sleeping") nociceptors have been shown to mediate the axon-reflex in human skin, sensitization of this class of nociceptors might contribute also to the UV-B-induced primary mechanical hyperalgesia.
Koppert
Wolfgang
W
Department of Anesthesiology, University of Erlangen, Germany.
Brueckl
Valeska
V
Weidner
Christian
C
Schmelz
Martin
M
D000328:Adult; D001369:Axons / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D002056:Burns / Q000150:complications* / Q000503:physiopathology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004333:Drug Administration Routes; D004890:Erythema / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology*; D008012:Lidocaine / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D010812:Physical Stimulation / Q000379:methods; D012018:Reflex / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects
D008012:Lidocaine