In CP-W, pinprick hyperalgesia and increased sensitivity to capsaicin were aligned with increased epidermal TRPV1 expression, while smaller histamine axon reflex erythema matched with significantly reduced intraepidermal nerve fiber density.
The prevention of this hyperalgesia by diclofenac (1-10μg), the inhibitors of COX-1 SC-560 (0.1-1μg) or COX-2 celecoxib (1-5μg), the TRPV1 antagonist capsazepine (0.03-0.3μg) or the TRPA1 antagonist HC030031 (10-50μg) demonstrates the involvement of prostaglandin synthesis and TRP sensitization in CCL5-evoked hyperalgesia.
That a proinflammatory chemokine, by interacting with its receptor on small-diameter neurons, sensitizes TRPV1 reveals a previously undescribed mechanism of receptor cross-sensitization that may contribute to hyperalgesia during inflammation.
Importantly, we found that interfering with TRPV1 subunit association using a plasma membrane-tethered peptide attenuated mechanical and thermal hypersensitivity in two mouse models of inflammatory hyperalgesia.
Peripheral group II metabotropic glutamate receptors (mGluR2/3) regulate prostaglandin E2-mediated sensitization of capsaicin responses and thermal nociception.
A strong connection has been suggested between the expression of the transient receptor potential vanilloid type 1 (TRPV1) ion channel and the development of inflammatory hyperalgesia.
Intrathecal administration of the TRPV1 siRNA not only attenuated behavioural hyperalgesia but also reduced the expression of TRPV1 and CAMKII, as well as ERK2 phosphorylation.
Beneficial effect of mirtazapine on diabetes-induced hyperalgesia: involvement of TRPV1 and ASIC1 channels in the spinal cord and dorsal root ganglion.
Because animals treated with opiates show thermal hyperalgesia, we examined the possible role of TRPV1 receptors in the development of morphine-induced hyperalgesia using TRPV1 wild-type (WT) and knock-out (KO) mice and with administration of a TRPV1 antagonist in mice and rats.
Similarly, NTG injection produced significant hindpaw mechanical allodynia or facial cold allodynia, but not heat hyperalgesia in transient receptor potential type V1 (TRPV1) knockout mice.
Following TNBS treatment, the successive administration of the transient receptor potential vanilloid 1 (TRPV1) antagonist SB366791 or neutralizing anti-Artn antibody completely inhibited the heat hyperalgesia.
Phα1β did not affect calcium responses evoked by selective TRPV1 (capsaicin) or TRPV4 (GSK 1016790A) agonists on the various cell types.Intrathecal (i.t.) and intraplantar (i.pl.) administration of low doses of Phα1β (up to 300 pmol per paw) attenuated acute nociception and mechanical and cold hyperalgesia evoked by AITC (i.t. or i.pl.), without affecting responses produced by capsaicin or hypotonic solution.
p38 signaling cascades are involved in tongue heat hyperalgesia in association with TRPV1 upregulation in TG neurons innervating the TNBS-treated tongue.
We conclude that one of the possible regulatory mechanisms of TNF in pain involves upregulation of the nociceptor TRPV1, and that peripheral treatment with a selective anti-soluble TNF biologic can prevent hyperalgesia caused by inflammation in the orofacial region.
Altogether, these results indicate that B vitamins can be useful to control heat hyperalgesia associated with trigeminal neuropathic pain and that modulation of TRPV1 receptors may contribute to their anti-hyperalgesic effects.
Spinally, the IL/mGluR5-induced behavioral heat hyperalgesia is mediated by TRPV1 and associated with facilitated heat-evoked responses of WDR and NS neurons.
Our data suggest that H<sub>2</sub>S leads to hyperalgesia in diabetic rats through activation of TRPV1, TRPA1 and TRPC channels and, subsequent intraepidermal fibers loss.