Transient Receptor Potential Vanilloid 1 - A Doubtful Ambitious Modality for Manipulation

Abstract

Sir,

Transient Receptor Potential Vanilloid 1 (TRPV1) is the most widely studied member of the TRPV family. They act as a non-selective cationic ligandgated channel on neuronal and non-neuronal cell membrane and highly permeable to calcium. TRPV1 is distributed widely in the peripheral nervous system, autonomic nervous system and different parts of the brain and essential organs such as the pancreas, liver, lung, kidney and heart. TRPV1 acts as a multisensory receptor for receiving potential injury signals, they can be activated by many exogenous and endogenous mediators that involve in physiological reactions, initiate inflammation and transmit pain signal.^[1] TRPV1 mediates secretion of proinflammatory factors such as tachykinin and calcitonin gene-related peptide (CGRP) in nerve endings that causes “neurogenic inflammation” which includes bronchoconstriction, tracheal mucosal edema, inflammatory cell chemo taxis and increased protein secretion. Exogenous and endogenous pro-inflammatory mediators such as capsaicin, resiniferatoxin, PGE2, citric acid and low pH lead to inflammation and chronic cough by increasing TRPV1 expression. TRPV1 can impair immune system by the action of a suppressor of interferon-gamma released by CGRP which is a critical cytokine for innate and adaptive immunity, activation of macrophages, stimulation of natural killer cells down-regulation and neutrophils to prevent virus replication and anti-inflammatory action by promoting some interleukins (IL-10). TRPV1 is a chemosensor in sympathetic neurons and promoter of airway inflammation in the non-neural system. All these evidences indicated that capsaicin, a TRPV1 agonist induces the release of IL-8, as a chemokine that triggers cytokine storm in infections while capsazepine, an antagonist of TRPV1 blocks the pro-inflammatory process.^[1-4] Read more...