Scientists from USA and Canada have discovered that calcium-permeable channels are present in cerebral arteries, which are colocalized with NADPH oxidase 2, a potent inducer of reactive oxygen species (ROS) in various cells. The scientists coined the term “TRPA1 sparklets” based on their discovery of ROS-triggered calcium signals representing calcium influx through single TRPA1 (transient receptor potential ankyrin 1) channels. In the publication in Science Signaling, they say that “TRPA1 sparklet activity was low under basal conditions but was stimulated by NOX-generated ROS. Ca2+ entry during a single TRPA1 sparklet was twice that of a TRPV4 sparklet and ~200 times that of an L-type Ca2+ channel sparklet. The NADPH oxidase-induced TRPA1 sparklets activated intermediate-conductance, Ca2+-sensitive K+ channels, resulting in smooth muscle hyperpolarization and vasodilation.” From their data, it comes to our knowledge that during circulation, cerebral arteries dilate due to lipid peroxidation metabolites generated by ROS activated Ca2+ influx through TRPA1 channels in the endothelium.
The article can be accessed at: http://stke.sciencemag.org/content/8/358/ra2.abstract
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