[Abstract Title]. - Society for Neuroscience

have agonist properties at selective TRP channels. Some of these chemicals produce a
neurogenic inflammatory response, which is produced by a locally-, as well as a centrallymediated
release of vasoactive peptides and thought to be important in some types of
inflammatory pain. For example, the TRPV1 agonist, capsaicin, produces an intense „burning‟
pain sensation followed by radiating areas of hyperalgesia and allodynia following intradermal or
topical administration. This inflammatory response is visible as a “flare” surrounding the site of
injection. Quantification of flare can be accomplished by using laser Doppler imaging, which
measures superficial blood flow in the skin.
In the present study, laser Doppler imaging was used to evaluate the flare response to TRP
agonists. The TRPV1, TRPA1, and TRPM8 agonists capsaicin (0.1 - 3 mg), mustard oil (0.3%-
10%), and menthol (50%), respectively, were topically administered in anesthetized rats.
Capsaicin dose-dependently produced flare, with the maximal flare response occurring 45 min
(191% increase from baseline) after application of 1 mg. When administered 120 min before
capsaicin, the selective TRPV1 antagonist, JNJ-17203212 (30 mg/kg; p.o), blocked the flare
response induced by topical administration of 0.3 mg capsaicin. Mustard oil, produced the
greatest flare response at 30 min (120% increase from baseline) at a concentration of 0.3%.
Higher concentrations of mustard oil produced less flare at the site of application, though flare
outside the area of application was substantially greater. The flare response to menthol was not
substantially different than that of vehicle. These results suggest that laser Doppler imaging can
be useful for evaluating compounds for their ability to modify the flare response produced by
TRP agonists.
Disclosures: V.A. Kenigs, Johnson & Johnson PR&D, A. Employment (full or part-time); M.R.
Brandt, Johnson & Johnson PRD, A. Employment (full or part-time); C.M. Flores, Johnson &
Johnson PR&D, A. Employment (full or part-time).
Poster
265. Nociceptors II
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 265.21/EE22
Topic: B.02.t. TRP Channels
Title: Development of a high-content automated electrophysiological assay combining TRPV1
pH and voltage-dependent activations
Authors: O. RADRESA, *S. ZICHA, M. VALIQUETTE, J. DUCHARME;
AstraZeneca R&D Montreal, St-Laurent, QC, Canada