1. Furanocoumarins are a novel class of modulators for the transient receptor potential vanilloid type 1 (TRPV1) channel.
- Author
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Chen X, Sun W, Gianaris NG, Riley AM, Cummins TR, Fehrenbacher JC, and Obukhov AG
- Subjects
- Analgesics chemistry, Angelica chemistry, Animals, Dermatologic Agents chemistry, Furocoumarins chemistry, HEK293 Cells, Humans, Mice, Mice, Knockout, NAV1.7 Voltage-Gated Sodium Channel genetics, NAV1.7 Voltage-Gated Sodium Channel metabolism, Nociception drug effects, Nociception physiology, Pain Management methods, Pain Measurement, Rats, TRPV Cation Channels genetics, TRPV Cation Channels metabolism, Analgesics pharmacology, Dermatologic Agents pharmacology, Furocoumarins pharmacology, TRPV Cation Channels agonists
- Abstract
Furanocoumarin imperatorin is the major active component of Angelica dahurica root extracts, widely used in traditional medicine to treat headache, toothache, and orbital eye pain. In this study, we investigated the mechanisms that may underlie the pain-relieving effects of the compound. We found that imperatorin significantly inhibited formalin- and capsaicin-induced nocifensive responses but did not alter baseline thermal withdrawal thresholds in the rat. We established that imperatorin is a weak agonist of TRPV1, a channel implicated in detecting several noxious stimuli, exhibiting a 50% effective concentration (EC50) of 12.6 ± 3.2 μM. A specific TRPV1 antagonist, JNJ-17203212 (0.5 μM), potently inhibited imperatorin-induced TRPV1 activation. Site-directed mutagenesis studies revealed that imperatorin most likely acted via a site adjacent to or overlapping with the TRPV1 capsaicin-binding site. TRPV1 recovery from desensitization was delayed in the presence of imperatorin. Conversely, imperatorin sensitized TRPV1 to acid activation but did not affect the current amplitude and/or the activation-inactivation properties of Na(v)1.7, a channel important for transmission of nociceptive information. Thus, our data indicate that furanocoumarins represent a novel group of TRPV1 modulators that may become important lead compounds in the drug discovery process aimed at developing new treatments for pain management.
- Published
- 2014
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