Trpv1

Abstract

TRPV1 is a well-characterised channel expressed by a subset of peripheral sensory neurons involved in pain sensation and also at a number of other neuronal and non-neuronal sites in the mammalian body. Functionally, TRPV1 acts as a sensor for noxious heat (greater than ~42 °C). It can also be activated by some endogenous lipid-derived molecules, acidic solutions (pH < 6.5) and some pungent chemicals and food ingredients such as capsaicin, as well as by toxins such as resiniferatoxin and vanillotoxins. Structurally, TRPV1 subunits have six transmembrane (TM) domains with intracellular N- (containing 6 ankyrin-like repeats) and C-termini and a pore region between TM5 and TM6 containing sites that are important for channel activation and ion selectivity. The N- and C- termini have residues and regions that are sites for phosphorylation/dephosphorylation and PI(4,5)P2 binding, which regulate TRPV1 sensitivity and membrane insertion. The channel has several interacting proteins, some of which (e.g. AKAP79/150) are important for TRPV1 phosphorylation. Four TRPV1 subunits form a non-selective, outwardly rectifying ion channel permeable to monovalent and divalent cations with a single-channel conductance of 50-100 pS. TRPV1 channel kinetics reveal multiple open and closed states, and several models for channel activation by voltage, ligand binding and temperature have been proposed. Studies with TRPV1 agonists and antagonists and Trpv1 (-/-) mice have suggested a role for TRPV1 in pain, thermoregulation and osmoregulation, as well as in cough and overactive bladder. TRPV1 antagonists have advanced to clinical trials where findings of drug-induced hyperthermia and loss of heat sensitivity have raised questions about the viability of this therapeutic approach.

Phosphoinositide signaling in somatosensory neurons

“…TRPV1 is a heat- and capsaicin-activated ion channel; it is probably the most intensively studied sensory ion channel (Bevan et al, 2014). Its role as a physiological heat sensor is somewhat debated (Dhaka et al, 2006), but it is very well established to be important for thermal hyperalgesia (Vriens et al, 2014b).…”

Privileged crosstalk between TRPV1 channels and mitochondrial calcium shuttling machinery controls nociception

“…Prolonged activation of TRPV1 channels leads to intracellular Ca 2+ overload, which causes Ca 2+ -dependent apoptosis and cell death [4][5][6]. A prominent feature of TRPV1 channels is their modulation by Ca 2+ [7]. Influx of Ca 2+ through the TRPV1 channels, followed by its intracellular accumulation, desensitizes the channels, thus regulating their activity [8][9][10].…”

Blocking Mammalian Target of Rapamycin (mTOR) Alleviates Neuropathic Pain Induced by Chemotherapeutic Bortezomib

“…It is well known that stimulation of nociceptive receptors in the sensory nerves leads to the releases of substance P and CGRP from the nerve terminal of dorsal root ganglions into the superficial dorsal horn [18,24]. Numerous receptors present on the presynaptic site of the nerve terminals and contribute to the releases of substance P and CGRP in regulating inflammatory pain [16].…”