TRP channels detect changes in external environment and internal states of the body and cells. They also detect cellular redox status mediated by reactive oxygen species and reducing species including molecular oxygen. It has been recognized by many researchers that the carotid body is the only major oxygen sonsor that induce adaptive changes in the body. Recently, we have found that in addition to the carotid body, vagus plays an important role in detecting oxygen availabity in the atomosphere by projecting to the airway, trachea and the lung. TRPA1 is responsible for this oxygen sensing ability of the vagus, and in fact detects both hyperoxia and hypoxia through oxydative modification of cysteine residues and supression of prolyl-hydroxylation,respectively, contrasting prominently with the well known roles of K channels in hypoxia sensing function of the carotid body glomus cells. In my presentation, I will provide evidence that supports our findings, and will refer to our effort to look for oxygen receptor organs ubiquitously localized in the body to control adaptaion of tissues and composing cells in response to changes in oxygen availabity externally and internally. I will also demonstrate some of our data on a series of substance which selectively activate TRPA1 channels via transnitrosylation and molecluar recognistion. TRPA1 and other TRP channels should be interesting targets for invention of chemical substances not only from medical aspects but also in understanding molecular nature of ion channel function.