The Journal of pharmacology and experimental therapeutics
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J. Pharmacol. Exp. Ther. · Jul 2005
A-425619 [1-isoquinolin-5-yl-3-(4-trifluoromethyl-benzyl)-urea], a novel transient receptor potential type V1 receptor antagonist, relieves pathophysiological pain associated with inflammation and tissue injury in rats.
The vanilloid receptor 1 (VR1, TRPV1), which is a member of the transient receptor potential (TRP) superfamily, is highly localized on peripheral and central processes of nociceptive afferent fibers. Activation of TRPV1 contributes to the pronociceptive effects of capsaicin, protons, heat, and various endogenous lipid agonists such as anandamide and N-arachidonoyl-dopamine. A-425619 [1-isoquinolin-5-yl-3-(4-trifluoromethyl-benzyl)urea] is a novel potent and selective antagonist at both human and rat TRPV1 receptors. ⋯ A-425619 also showed partial efficacy in models of neuropathic pain. A-425619 did not alter motor performance at the highest dose tested (300 micromol/kg p.o.). Taken together, the present data indicate that A-425619, a potent and selective antagonist of TRPV1 receptors, effectively relieves acute and chronic inflammatory pain and postoperative pain.
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J. Pharmacol. Exp. Ther. · Jul 2005
Role of transient receptor potential vanilloid 1 receptors in adjuvant-induced chronic arthritis: in vivo study using gene-deficient mice.
The transient receptor potential vanilloid 1 (TRPV1) receptor is a nonselective cation channel localized on a subset of primary sensory neurons and can be activated by a wide range of stimuli. The present study investigated the role of this receptor in chronic arthritis evoked by complete Freund's adjuvant (CFA) using TRPV1 receptor gene-deleted (TRPV1-/-) mice and wild-type counterparts (TRPV1+/+). In TRPV1+/+ mice, CFA injected intraplantarly into the left hindpaw and the root of the tail induced swelling of the injected and contralateral paws up to 130 and 28%, respectively, measured by plethysmometry throughout 18 days. ⋯ The effect of indomethacin was markedly smaller in knockouts. In TRPV1+/+ animals, HOE-140, but not desArgHOE-140, inhibited arthritis, whereas in TRPV1-/- mice, HOE-140 produced limited effect. Thus, whereas bradykinin and lipoxygenase products seem to act exclusively via TRPV1 activation, prostanoids do not, or at least only partially, to enhance murine experimental arthritis and related hyperalgesia.