Erythropoietin (EPO) regulates respiration under conditions of normoxia and hypoxia through interaction with the respiratory centers brainstem. Here we investigate dose-dependent impact EPO in CB response to hypercapnia. We show, isolated “ en bloc ” carotid body (CB) preparations containing sinus nerve (CSN) from adult male Sprague Dawley rats, that acts as a stimulator CSN activity at concent...

Current protective lung ventilation strategies commonly involve hypercapnia. This approach has resulted in an increase in the clinical acceptability of elevated carbon dioxide tension, with hypoventilation and hypercapnia 'permitted' in order to avoid the deleterious effects of high lung stretch. Advances in our understanding of the biology of hypercapnia have prompted consideration of the pote...

Ooi, Henry, Elaine Cadogan, Michèle Sweeney, Katherine Howell, R. G. O’Regan, and Paul McLoughlin. Chronic hypercapnia inhibits hypoxic pulmonary vascular remodeling. Am. J. Physiol. Heart Circ. Physiol. 278: H331–H338, 2000.—Chronic hypercapnia is commonly found in patients with severe hypoxic lung disease and is associated with a greater elevation of pulmonary arterial pressure than that due ...

Chronic hypercapnia is commonly found in patients with severe hypoxic lung disease and is associated with a greater elevation of pulmonary arterial pressure than that due to hypoxia alone. We hypothesized that hypercapnia worsens hypoxic pulmonary hypertension by augmenting pulmonary vascular remodeling and hypoxic pulmonary vasoconstriction (HPV). Rats were exposed to chronic hypoxia [inspirat...

The renin response to hypoxia in late gestation fetal sheep has been well characterized. However, the renin response to asphyxia-the combination of hypoxia and hypercapnia-has not been extensively studied. The purpose of this study was to determine 1) the interaction of hypoxia and hypercapnia in the control of renin secretion in late gestation fetal sheep and 2) the role of peripheral arterial...

BACKGROUND The arterial partial pressure of carbon dioxide (PaCO2) represents the balance between CO2 production and consumption. Abnormal increase or decrease in PaCO2 can affect the body's internal environment and function. Permissive hypercapnia has aroused more attention as a novel ventilatory therapy. The aim of this study was to elucidate the effects of hypercapnia and hypocapnia on the f...

BACKGROUND AND PURPOSE The purpose of these experiments was to examine mechanisms by which hypercapnia produces vasodilatation in brain. We examined the hypothesis that dilatation of cerebral arterioles during hypercapnia is dependent on activation of ATP-sensitive potassium channels and formation of nitric oxide. METHODS Diameters of cerebral arterioles were measured using a closed cranial w...

Acute hypercapnia may develop during periodic breathing from an imbalance between abnormal ventilatory patterns during apnea and/or hypopnea and compensatory ventilatory response in the interevent periods. However, transition of this acute hypercapnia into chronic sustained hypercapnia during wakefulness remains unexplained. We hypothesized that respiratory-renal interactions would play a criti...

Animals with intermittent lung ventilation and those exposed to hypoxia and hypercapnia will experience fluctuations in the bodily O2 and CO2 stores, but the magnitude and duration of these changes are not well understood amongst ectotherms. Using the changes in the respiratory exchange ratio (RER; CO2 excretion divided by O2 uptake) as a proxy for changes in bodily gas stores, we quantified ti...