Reactive oxygen species are the cause of the enhanced cardiorespiratory response induced by intermittent hypoxia in conscious rats.
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.
Kuo
Terry B J
TB
Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.
Yuan
Zung Fan
ZF
Lin
You Shuei
YS
Lin
Yi-Ning
YN
Li
Weng-Shan
WS
Yang
Cheryl C H
CC
Lai
Ching Jung
CJ
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
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