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Effects of transient receptor potential (TRP) channel agonists and antagonists on slowly adapting type II mechanoreceptors in the rat sinus hair follicle
Author(s) -
Cahusac Peter M.B.
Publication year - 2009
Publication title -
journal of the peripheral nervous system
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 67
eISSN - 1529-8027
pISSN - 1085-9489
DOI - 10.1111/j.1529-8027.2009.00242.x
Subject(s) - capsazepine , transient receptor potential channel , chemistry , mechanoreceptor , stimulus (psychology) , trpv1 , electrophysiology , hair follicle , medicine , endocrinology , stimulation , receptor , biology , biochemistry , psychology , psychotherapist
The possible functional role of transient receptor potential (TRP) channels was investigated by testing various TRP agonists and antagonists in an isolated rat sinus hair follicle preparation. Extracellular recordings from slowly adapting type II mechanoreceptor units were made. The antagonist capsazepine depressed spontaneous and mechanically evoked activity, with an IC 50 of 82 µM. In one‐third of units, capsazepine caused a selective depression of mechanically evoked firing, such that the existing spontaneous firing was interrupted by an absence of activity during the mechanical stimulus. The broad spectrum TRP blocker ruthenium red (30 µM) had inconsistent effects, although in some units a delayed onset (following wash) bursting and paroxysmal firing ensued. The agonist icilin (50–100 µM) had an excitatory effect on spontaneous firing, and (‐)‐menthol (200 µM) had inconsistent effects. Cinnamaldehyde (1–2 mM) depressed all types of activity equally, mechanically evoked and spontaneous. Camphor (0.5–2 mM) also depressed all types of activity, although it had a preferential effect on spontaneous activity. Capsaicin (1–10 µM) and allyl isothiocyanate (50–100 µM) had no clear effects. These results rule out any role for TRPA1 and TRPV1 channels in mechanotransduction processes of slowly adapting type II mechanoreceptors.