BACKGROUND The activation of ATP-sensitive K+ (K+ ATP) channels by K+ ATP openers, eg, pinacidil, hypoxia, and ischemia, is known to shorten the ventricular action potential. Since adenosine is released in increased amounts during cardiac hypoxia and ischemia, the hypothesis that endogenous adenosine activates K+ ATP channels was tested in vivo in a guinea pig model. METHODS AND RESULTS Anest...

ARTERIAL CHEMORECEPTORS LOCATED in the carotid body are an important defense mechanism against systemic hypoxemia. Activation of arterial chemoreceptors increases alveolar ventilation and sympathetic outflow to most vascular beds. During acute exposures to hypoxia, the sympathoexcitatory responses to chemoreceptor activation are important in counteracting the direct vasodilator effects of hypox...

Intermittent hypoxia caused by sleep apnea is associated with cardiovascular disease. Chymase has been reported to play an important role in the development of cardiovascular disease, but it is unclear whether chymase is involved in the pathogenesis of left ventricular remodeling induced by intermittent hypoxia. The aim of this study was to evaluate the effect of a novel chymase inhibitor (NK32...

Late-gestational intrauterine hypoxia represents a well-known risk factor of acquired perinatal brain injury. Cell type and age-specific sensitivity of hypoxia-responsive genes to low-oxygen partial pressure is to be considered in the screening for early indicators of fetoplacental tissue hypoxia. To identify early hypoxia-induced alterations in gene expression during late-gestational hypoxia (...

Intrauterine growth restriction (IUGR) is a common pregnancy complication and is a leading cause of fetal morbidity and mortality. Placental hypoxia contributes to adverse fetal consequences, such as IUGR. Exposing pregnant rats to hypoxia can lead to IUGR; however, assessment of maternal vascular function in a rat model of hypoxia, and the mechanisms that may contribute to adverse pregnancy ou...

Endothelin-1 (ET-1) is considered an intermediary in the constrictor response of the pulmonary vasculature to hypoxia and, by extension, is assigned a prime role in the pathogenesis of pulmonary hypertension. We report here the antihypertensive action in the conscious newborn lamb of two novel endothelin A receptor antagonists, sodium 2-benzo-[1,3]dioxol-5-yl-4- (4-methoxy-phenyl)-4-oxo-3-(3,4,...

Chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea, enhances carotid body (CB) chemosensory responses to hypoxia and produces autonomic dysfunction, cardiac arrhythmias, and hypertension. We tested whether autonomic alterations, arrhythmogenesis, and the progression of hypertension induced by CIH depend on the enhanced CB chemosensory drive, by ablation of the CB ch...

Systemic hypoxia results in oxidative stress due to a change in the reactive oxygen species (ROS)-nitric oxide (NO) balance. These experiments explored two mechanisms for the altered ROS-NO balance: 1) decreased NO synthesis by NO synthase due to limited O(2) substrate availability and 2) increased superoxide generation. ROS levels and leukocyte adherence in mesenteric venules of rats during hy...

Hypoxia-inducible factor, a heterodimeric transcription complex, regulates cellular and systemic responses to low oxygen levels (hypoxia) during normal mammalian development or tumor progression. Here, we present evidence that a similar complex mediates response to hypoxia in Caenorhabditis elegans. This complex consists of HIF-1 and AHA-1, which are encoded by C. elegans homologs of the hypoxi...

Normal brain function is highly dependent on oxygen and nutrient supply and when the demand for oxygen exceeds its supply, hypoxia is induced. Acute episodes of hypoxia may cause a depression in synaptic activity in many brain regions, whilst prolonged exposure to hypoxia leads to neuronal cell loss and death. Acute inadequate oxygen supply may cause anaerobic metabolism and increased respirati...