title: Responsiveness of electrical nociceptive detection thresholds to capsaicin (8 %)-induced changes in nociceptive processing.
abstract: Pain disorders can be initiated and maintained by malfunctioning of one or several mechanisms underlying the nociceptive function. Psychophysical procedures allow the estimation of nociceptive detection thresholds using intra-epidermal electrical stimuli. By varying the temporal properties of electrical stimuli, various contributions of nociceptive processes to stimulus processing can be observed. To observe the responsiveness of nociceptive thresholds to changes in nociceptive function, a model of capsaicin-induced nerve defunctionalization was used. Its effect on nociceptive detections thresholds was investigated over a period of 84 days. A cutaneous capsaicin (8 %) patch was applied for 60 min to the upper leg of eight healthy human participants. Single- and double-pulse electrical stimuli were presented in a pseudo-random order using an intra-epidermal electrode. Stimuli and corresponding responses were recorded on both treated and untreated skin areas prior to capsaicin application and on days 2, 7, 28, and 84. Increases in electrical detection thresholds at the capsaicin area were observed on days 2 and 7 for single-pulse stimuli. Detection thresholds corresponding to double-pulse stimuli were increased on days 7 and 28, suggesting a delayed and longer lasting effect on double-pulse stimuli. In the present study, it was demonstrated that the responsiveness of detection thresholds to capsaicin application depends on the temporal properties of electrical stimuli. The observation of capsaicin-induced changes by estimation of detection thresholds revealed different time patterns of contributions of peripheral and central mechanisms to stimulus processing.
authors.affiliation: Biomedical Signals and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Zuidhorst, ZH-222, Drienerlolaan 5, PO BOX 217, Enschede, The Netherlands. r.j.doll@utwente.nl.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Doll
authors.affiliation: Centre for Human Drug Research, Leiden, The Netherlands.
authors.forename: Guido
authors.initials: G
authors.lastname: van Amerongen
authors.affiliation: Centre for Human Drug Research, Leiden, The Netherlands.
authors.forename: Justin L
authors.initials: JL
authors.lastname: Hay
authors.affiliation: Centre for Human Drug Research, Leiden, The Netherlands.
authors.forename: Geert J
authors.initials: GJ
authors.lastname: Groeneveld
authors.affiliation: Biomedical Signals and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Zuidhorst, ZH-222, Drienerlolaan 5, PO BOX 217, Enschede, The Netherlands.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Veltink
authors.affiliation: Biomedical Signals and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Zuidhorst, ZH-222, Drienerlolaan 5, PO BOX 217, Enschede, The Netherlands.
authors.forename: Jan R
authors.initials: JR
authors.lastname: Buitenweg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002211:Capsaicin / Q000494:pharmacology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000187:drug effects* / Q000502:physiology; D010812:Physical Stimulation / Q000379:methods; D011601:Psychophysics / Q000379:methods; D012867:Skin / Q000187:drug effects* / Q000294:innervation; D055815:Young Adult
chemical_list: D002211:Capsaicin
keywords: Capsaicin; Intra-epidermal electrical stimulation; Nociception; Psychophysics