title: Reactive oxygen species are the cause of the enhanced cardiorespiratory response induced by intermittent hypoxia in conscious rats.
abstract: This study was carried out to investigate the role of reactive oxygen species (ROS) in the elevation of cardiorespiratory responses during the development of intermittent hypoxia (IH)-induced hypertension. Rats were exposed to either 30 days of IH [(30s N₂)+(45 s room air (RA)] or RA for 6 h/day. After 5 days of exposure, stable mean arterial pressure, normalized low-frequency power of pulses interval spectrogram (a marker of cardiac sympathetic outflow), and minute ventilation (an index for arterial chemoreflex activation) were significantly increased throughout the observation period in IH-exposed rats, but not in RA-exposed rats. FosB expression in rostral ventrolateral medulla was elevated after IH exposure for 5 days. Intraperitoneal injection of MnTMPyP (a superoxide scavenger) or N-acetylcysteine (an antioxidant) prevented IH-induced elevation of the cardiorespiratory responses and lipid peroxidation of lung tissues. These results suggest that ROS are essential for IH-induced elevation of arterial chemoreflex activation and sympathetic outflow, which may, in turn, contribute to IH-induced hypertension.
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Terry B J
authors.initials: TB
authors.lastname: Kuo
authors.forename: Zung Fan
authors.initials: ZF
authors.lastname: Yuan
authors.forename: You Shuei
authors.initials: YS
authors.lastname: Lin
authors.forename: Yi-Ning
authors.initials: YN
authors.lastname: Lin
authors.forename: Weng-Shan
authors.initials: WS
authors.lastname: Li
authors.forename: Cheryl C H
authors.initials: CC
authors.lastname: Yang
authors.forename: Ching Jung
authors.initials: CJ
authors.lastname: Lai
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D016166:Free Radical Scavengers / Q000494:pharmacology; D000860:Hypoxia / Q000473:pathology / Q000503:physiopathology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism; D008665:Metalloporphyrins / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000494:pharmacology*; D012018:Reflex / Q000187:drug effects; D013057:Spectrum Analysis / Q000379:methods; D014851:Wakefulness
chemical_list: C483820:Fosb protein, rat; D016166:Free Radical Scavengers; D008665:Metalloporphyrins; C502230:Mn(III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin; D016760:Proto-Oncogene Proteins c-fos; D017382:Reactive Oxygen Species; D000111:Acetylcysteine