TRPV1 and TRPA1 in Pulmonary Vagal Afferents and their Relations to Airway Sensitivity

Hiroyuki      Watanabe; Takayoshi      Ohba; Kazuhiro      Satoh; Masaaki      Sano; Takanobu      Shioya; Hiroshi      Ito

Abstract

In the last 15 years, studies of transient receptor potential (TRP) channels have significantly extended our knowledge about the molecular basis of sensory function in pulmonary vagal afferents. In particular, TRPV1 and TRPA1 channels are unique cellular sensors for a wide range of inflammatory mediators and noxious irritants. These channels act as the molecular integrator of multiple nociceptive stimuli and are involved in multiple cellular functions, ranging from transduction of sensory signals to the release of neuropeptides in pulmonary vagal afferents. Increased activity of TRPV1 channels is now recognized as a cause of airway hypersensitivity in inflammatory airway diseases. In this review, we summarize current knowledge about the activation mechanisms of TRPV1 and TRPA1, and discuss the possible functional implications of TRPV1 and TRPA1 in human physiology and pathophysiology, such as the cough reflex and hypersensitivity.

Keywords: TRPV1, TRPA1, hypersensitivity, cough, pulmonary vagal afferents, irritants, resiniferatoxin, A-fibers, 2-aminoethoxy diphenyl borate, Non-anaesthetised