title: A human surrogate model of itch utilizing the TRPA1 agonist trans-cinnamaldehyde.
abstract: The thermoreceptive transient receptor potential ankyrin 1 (TRPA1) is important in the transmission of itch, and its agonist trans-cinnamaldehyde has occasionally been reported to be a pruritogen in humans. However, no studies have accurately quantified the capabilities of trans-cinnamaldehyde to induce itch and related dysesthetic sensations. The present study examined alterations in somatosensory and vasomotor parameters in response to topical trans-cinnamaldehyde 5% and vehicle (ethanol) in 24 healthy subjects. During the study the following parameters were recorded: itch area and intensity, hyperknesis, alloknesis, neurogenic flare, skin blood flow and temperature. Trans-cinnamaldehyde evoked moderate itch sensation, flare, hyperknesis and alloknesis (p < 0.001). Blood flow and skin temperature were elevated in the area of trans-cinnamaldehyde application (p < 0.001). Significant positive correlations were found between blood flow and skin temperature, itch area and blood flow, and itch area and skin temperature. Topical trans-cinnamaldehyde proved feasible as a human itch model with applicability in studying itch mechanisms or anti-pruritic drug profiling.
authors: Center for Sensory-Motor Interaction (SMI), Department of Health science and Technology, Aalborg University, Aalborg, Denmark.
authors: Chris R
authors: CR
authors: Højland
authors: Hjalte H
authors: HH
authors: Andersen
authors: Jeppe N
authors: JN
authors: Poulsen
authors: Lars
authors: L
authors: Arendt-Nielsen
authors: Parisa
authors: P
authors: Gazerani
mesh_terms: D000171:Acrolein / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000279:Administration, Cutaneous; D015220:Calcium Channels / Q000378:metabolism; D005240:Feasibility Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007509:Irritants / Q000008:administration & dosage*; D008297:Male; D009419:Nerve Tissue Proteins / Q000819:agonists* / Q000378:metabolism; D011537:Pruritus / Q000139:chemically induced* / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology; D012039:Regional Blood Flow; D012720:Severity of Illness Index; D012867:Skin / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D012881:Skin Temperature; D000074025:TRPA1 Cation Channel; D013997:Time Factors; D050051:Transient Receptor Potential Channels / Q000819:agonists* / Q000378:metabolism; D055815:Young Adult
chemical_list: D015220:Calcium Channels; D007509:Irritants; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050051:Transient Receptor Potential Channels; D000171:Acrolein; C012843:cinnamaldehyde