TRPV1-mediated itch in seasonal allergic rhinitis.
BACKGROUND
Patients with allergic rhinitis may be abnormally sensitive to stimulation of the ion channel transient receptor potential vanilloid-1 (TRPV1).


OBJECTIVE
To examine effects of various TRP ion channel activators on sensory symptoms in allergic rhinitis prior to and during seasonal allergen exposure.


METHODS
Nasal challenges were carried out with the TRPV1-activators capsaicin, anandamide and olvanil. Moreover, challenges were performed with mustard oil (allylisothiocyanate) and cinnamaldehyde as well as menthol, activators of TRPA1 and TRPM8, respectively. Nasal symptoms were monitored after each challenge and compared with symptoms reported following corresponding sham challenges. Symptoms recorded after challenge prior to pollen season were also compared with challenge-induced symptoms during pollen season.


RESULTS
The TRPV1, TRPA1 and TRPM8-activators produced sensory symptoms dominated by pain and smart. During seasonal allergen exposure, but not prior to season, TRPV1-activators also induced itch. Furthermore, the seasonal challenge to the TRPV1-activator olvanil was associated with rhinorrhoea.


CONCLUSIONS
Patients with allergic rhinitis feature an increased itch response to TRPV1 stimulation at seasonal allergen exposure. We suggest that this reflects part of the hyperresponsiveness that characterizes on-going allergic rhinitis. Intervention with the TRPV1-signalling pathway may offer potential treatments of this condition.
Alenmyr
L
L
Department of Clinical Chemistry and Pharmacology, Lund University Hospital, Lund, Sweden.
Högestätt
E D
ED
Zygmunt
P M
PM
Greiff
L
L
D000171:Acrolein / Q000031:analogs & derivatives / Q000494:pharmacology; D000328:Adult; D000485:Allergens / Q000276:immunology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D000982:Antipruritics / Q000494:pharmacology; D001095:Arachidonic Acids / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000276:immunology; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D063388:Endocannabinoids; D006801:Humans; D008610:Menthol / Q000494:pharmacology; D009149:Mustard Plant; D009299:Nasal Provocation Tests; D009419:Nerve Tissue Proteins / Q000819:agonists / Q000276:immunology; D010938:Plant Oils / Q000494:pharmacology; D053284:Polyunsaturated Alkamides / Q000494:pharmacology*; D011537:Pruritus / Q000139:chemically induced* / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*; D018689:Sensory System Agents / Q000494:pharmacology; D012720:Severity of Illness Index; D000074025:TRPA1 Cation Channel; D050053:TRPM Cation Channels / Q000819:agonists / Q000276:immunology; D050916:TRPV Cation Channels / Q000819:agonists* / Q000276:immunology; D050051:Transient Receptor Potential Channels / Q000819:agonists / Q000276:immunology
D000485:Allergens; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000982:Antipruritics; D001095:Arachidonic Acids; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D063388:Endocannabinoids; D009419:Nerve Tissue Proteins; D010938:Plant Oils; D053284:Polyunsaturated Alkamides; D018689:Sensory System Agents; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050053:TRPM Cation Channels; C425966:TRPM8 protein, human; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D050051:Transient Receptor Potential Channels; D008610:Menthol; C054256:olvanil; D000171:Acrolein; D002211:Capsaicin; C012843:cinnamaldehyde; C027793:mustard oil; C078814:anandamide