EFFECTS OF REACTIVE OXYGEN SPECIES ON INTRACELLULAR CALCIUM IN BOVINE TRACHEAL EPITHELIUM: Modulation by Nitric Oxide

• Published in: Experimental lung research Vol. 26; no. 5; pp. 335 - 348
• Main Author: Soichiro Kanoh, Mitsuko Kondo, Jun Tamaoki, Hideo Kobayashi, Kazuo Motoyoshi, Atsushi Nagai
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Informa UK Ltd 2000; Taylor & Francis
• Subjects: Air breathing; Animals; Biological and medical sciences; Calcium - metabolism; Catalase - pharmacology; Cattle; Cells, Cultured; Dose-Response Relationship, Drug; Epithelium - drug effects; Epithelium - metabolism; Fundamental and applied biological sciences. Psychology; Hydrogen Peroxide - metabolism; Hypoxanthine - pharmacology; Intracellular Calcium Nitric Oxide Reactive Oxygen Species; L-Lactate Dehydrogenase - metabolism; Nitric Oxide - pharmacology; Nitroprusside - pharmacology; Phenanthrolines - pharmacology; Reactive Oxygen Species - physiology; Respiratory system: anatomy, metabolism, gas exchange, ventilatory mechanics, respiratory hemodynamics; Superoxide Dismutase - pharmacology; Superoxides - pharmacology; Thiourea - analogs & derivatives; Thiourea - pharmacology; Trachea - drug effects; Trachea - metabolism; Vertebrates: respiratory system; Xanthine Oxidase - pharmacology; Oxidative stress; Oxygen; Calcium; Respiratory epithelium; Ox; Respiratory system; Free radical; Respiratory tract; Vertebrata; Mammalia; Nitric oxide; Artiodactyla; Intracellular; Trachea; Ungulata
• ISSN: 0190-2148; 1521-0499
• DOI: 10.1080/019021400408290

We studied the effects of reactive oxygen species (ROS) on intracellular Ca 2+ concentration (\[Ca2+]i) and their possible modulation by nitric oxide (NO) in fura-2-loaded cultured bovine tracheal epithelium. Hypoxanthine (HX) and xanthine oxidase (XO), which generate superoxide anion (O2-) and hydrogen peroxide (H2O2), dose dependently increased \[Ca2+]i. The increase in \[Ca2+]i was reduced in the presence of superoxide dismutase (SOD, 200 U/mL) and catalase (200 U/mL) by 29% and 43%, respectively. The iron chelator o-phenanthroline and the hydroxyl radical (OH) scavenger dimethylthiourea (DMTU) more potently inhibited the response of \[Ca2+]i. H2O2- derived OH generated by the Fenton reaction caused a marked \[Ca2+]i elevation, but exogenous H2O2 did not. Sodium nitroprusside (100 muM), an NO donor, potentiated HX-XO induced \[Ca2+]i rise by 50%, an effect that was abolished in the presence of SOD or DMTU. These results suggest that OH formed by interaction of O2- and H2O2 in the presence of iron may play a major role in the HX-XO induced disruption of airway epithelial Ca 2+ homeostasis, and that NO potentiates ROS-induced \[Ca2+]i response, presumably by reacting with O2- and producing OH.