H₂O₂ Sensors of Lungs and Blood Vessels and Their Role in the Antioxidant Defense of the Body

V. P. Skulachev

Department of Bioenergetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-0338; E-mail: skulach@genebee.msu.su

Received April 2, 2001; Revision received August 2, 2001

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This paper considers the composition and function of sensory systems monitoring H₂O₂ level by the lung neuroepithelial cells and carotid bodies. These systems are localized in the plasma membrane of the corresponding cells and are composed of O₂^*--generating NADPH-oxidase and an H₂O₂-activated K⁺ channel. This complex structure of the H₂O₂ sensors is probably due to their function in antioxidant defense. By means of these sensors, an increase in the H₂O₂ level in lung or blood results in a decrease in lung ventilation and constriction of blood vessels. This action lowers the O₂ flux to the tissues and, hence, intracellular [O₂]. The [O₂] decrease, in turn, inhibits intracellular generation of reactive oxygen species. The possible roles of such systems under normal conditions (e.g., the effect of O₂^*- in air) and in some pathologies (e.g., pneumonia) is discussed.

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KEY WORDS: reactive oxygen species, H₂O₂ sensor, neuroepithelial cells, lung, carotid bodies

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