title: Pain perception in healthy volunteers: effect of repeated exposure to experimental systemic inflammation.
abstract: We aimed to study the relationship between pain perception and cytokine release during systemic inflammation. We present a randomized crossover trial in healthy volunteers (n = 17) in 37 individual trials. Systemic inflammation was induced by an i.v. bolus of Escherichia coli LPS (2 ng/kg) on two separate trial days, with or without a nicotine patch applied 10 h previously. Pain perception at baseline, and 2 and 6 h after LPS was assessed by pressure algometry and tonic heat stimulation at an increasing temperature (45-48℃) during both trials. Compared with baseline, pain pressure threshold was reduced 2 and 6 h after LPS, while heat pain perception was accentuated at all testing temperatures after 2 but not 6 h. The magnitude of changes in pain perception did not correlate to cytokine release. No effect of transdermal nicotine or training status was observed. In conclusion, LPS administration in healthy human volunteers leads to reduction in pain pressure threshold and an increase in pain perception to heat stimuli, supporting a relationship between acute systemic inflammation and pain perception.
authors.affiliation: Center of Inflammation and Metabolism, CIM 7641, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark Department of Anesthesiology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark susanne.janum.01@regionh.dk.
authors.forename: Susanne
authors.initials: S
authors.lastname: Janum
authors.affiliation: Center of Inflammation and Metabolism, CIM 7641, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Signe T
authors.initials: ST
authors.lastname: Nielsen
authors.affiliation: Multidisciplinary Pain Center, Department of Neuroanesthesiology, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Mads U
authors.initials: MU
authors.lastname: Werner
authors.affiliation: Coordinating Research Centre, Frederiksberg Hospital, Frederiksberg, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Mehlsen
authors.affiliation: Institute of Surgical Pathophysiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Kehlet
authors.affiliation: Department of Neuroanesthesiology, Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Møller
mesh_terms: D000293:Adolescent; D000328:Adult; D002908:Chronic Disease; D018592:Cross-Over Studies; D016207:Cytokines / Q000378:metabolism*; D019446:Endotoxemia / Q000503:physiopathology*; D064368:Healthy Volunteers; D006358:Hot Temperature; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology*; D007249:Inflammation / Q000503:physiopathology*; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D058748:Pain Perception; D017288:Pain Threshold; D011312:Pressure; D061485:Tobacco Use Cessation Devices / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides
keywords: Systemic inflammation; heat stimulus; human endotoxemia; hyperalgesia; pain perception; pressure algometry