Journal
CELL CALCIUM
Volume 45, Issue 2, Pages 155-164Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.ceca.2008.08.001
Keywords
Transient receptor potential channels; Calcium homeostasis; Ultraviolet light; Hydrogen peroxide; Photosensitiser; Hypericin
Categories
Ask authors/readers for more resources
TRPA1, a Ca2+-permeable cation channel that is expressed in sensory neurones, is involved in the perception of chemical irritants and mechanical hyperalgesia. TRPA1 is activated by either covalent or reversible binding of various chemical compounds, including allylisothiocyanate or acrolein, and is further sensitised by increases in the intracellular Ca2+ concentration. We here demonstrate that TRPA1 confers a sensitivity towards near ultraviolet (UVA) light, which rapidly causes Ca2+ entry. In electrophysiological recordings in whole cell and inside out modes, exposure to UVA light activated typical TRPA1 currents in a wavelength-dependent and membrane-delimited manner. In the presence of the photosensitising agents acridine orange (100 nM) or hypericin (10 nM), the sensitivity of light-induced TRPA1 activation was increased and extended towards the visible spectrum. Since extracellular application of hydrogen peroxide mimicked the effect of UVA irradiation and since dithiothreitol partly reversed the activation by UVA exposure, we conclude that reactive oxygen species may mediate the light-induced activation of TRPA1. Accordingly, hydrogen peroxide induced a TRPA1 activation with a membrane-delimited mode of action that was attenuated by dithiothreitol. Intracellular but not extracellular application of FeSO4, which catalyses the formation of highly reactive hydroxyl radicals potentiated the hydrogen peroxide-stimulated TRPA1 activation. We conclude that, via generation of reactive oxygen species, light-induced TRPA1 activation provides an additional mode of activation, which renders TRPA1 a likely molecular candidate in processes leading to painful or burning sensations during photodynamic therapy or upon local application of hydrogen peroxide. (C) 2008 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available