title: Response of human oral mucosa and skin to histamine provocation: laser Doppler perfusion imaging discloses differences in the nociceptive nervous system.
abstract: OBJECTIVE
  To investigate the existence of histamine-excitable nerve fibers in the oral mucosa and to compare the response to histamine provocation in healthy volunteers with that in a small group of patients with chronic oral pain.
  
  
  METHODS
  Thirteen healthy volunteers and six patients suffering from chronic oral pain took part in the study. Blood perfusion was monitored in the hard palate, the tongue, and the skin of the cheek using laser Doppler perfusion imaging (Perimed; Sweden). Baseline scannings were performed, followed by 15 scannings after iontophoresis of histamine (1%). A free description of the sensations was then obtained from the participants after finishing the measurements.
  
  
  RESULTS
  Compared to pre-histamine scanning, histamine application resulted in a considerable increase in blood perfusion in all regions (p<0.001) that was significantly higher in skin than in oral mucosa (p<0.001). There were no significant differences between the healthy volunteers and the patients regarding baseline blood flow, increased blood perfusion, or flare size after histamine provocation. The sensory impression was reported to be more persistent and intense in the skin than in the oral mucosa. No effect on mucosa could be detected by visual inspection.
  
  
  CONCLUSIONS
  Intra-oral flare could be induced by activating histamine-excitable nerve fibers. Both duration and intensity of the flare were considerably less pronounced than in the control skin site. Histamine application was not clearly associated with itch.
authors.affiliation: Institute of Odontology, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Bay
authors.forename: Marita
authors.initials: M
authors.lastname: Hilliges
authors.forename: Christian
authors.initials: C
authors.lastname: Weidner
authors.forename: Gunilla
authors.initials: G
authors.lastname: Sandborgh-Englund
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001369:Axons / Q000187:drug effects; D002054:Burning Mouth Syndrome / Q000150:complications / Q000503:physiopathology*; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006801:Humans; D007478:Iontophoresis; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009059:Mouth Diseases / Q000150:complications / Q000503:physiopathology; D009061:Mouth Mucosa / Q000098:blood supply / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology*; D009437:Neuralgia / Q000150:complications / Q000503:physiopathology*; D018377:Neurotransmitter Agents / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects*; D017288:Pain Threshold / Q000187:drug effects; D012016:Reference Values; D012018:Reflex / Q000187:drug effects; D012867:Skin / Q000098:blood supply / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology
chemical_list: D018377:Neurotransmitter Agents; D006632:Histamine