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Jornal Brasileiro de Pneumologia :... 2011
Topics: Diagnostic Imaging; Humans; Pulmonary Circulation
PubMed: 21755196
DOI: 10.1590/s1806-37132011000300001 -
The American Journal of Physiology Jul 1993We examined the role of endothelium-derived relaxing factor (EDRF) in the increase in pulmonary blood flow caused by increasing oxygen tension in the lungs of the fetus....
We examined the role of endothelium-derived relaxing factor (EDRF) in the increase in pulmonary blood flow caused by increasing oxygen tension in the lungs of the fetus. Fetal lambs at 133 days of gestation were instrumented for intrauterine measurement of pulmonary arterial, left atrial, and amniotic fluid pressure and pulmonary blood flow. Three days later oxygen tension in the pulmonary arterial blood of the fetus was doubled by having the ewe breathe 100% oxygen at 3 atm absolute pressure. In the control fetuses (n = 5), hyperbaric oxygenation increased pulmonary blood flow eightfold. Blocking EDRF production by infusing 45 mg of NG-monomethyl-L-arginine into the superior vena cava of the fetus over 5 min starting 30 min after the beginning of hyperbaric oxygen reversed the increase in pulmonary blood flow (n = 5). Blocking EDRF production by infusing NG-nitro-L-arginine at 1 mg/min for 60 min starting 30 min before hyperbaric oxygen blunted the initial increase in pulmonary blood flow and eliminated it by the end of the experiment (n = 5). As hyperbaric oxygen did not significantly alter pulmonary arterial or left atrial pressure, changes in pulmonary vascular conductance paralleled those in pulmonary blood flow. We conclude that the majority of the vasodilation of the fetal pulmonary circulation caused by increasing oxygen tension is mediated by EDRF. We speculate that EDRF is involved in maintaining low vascular tone at the relatively high oxygen tension of the postnatal lung.
Topics: Animals; Arginine; Fetus; Hemodynamics; Hyperbaric Oxygenation; Nitric Oxide; Nitroarginine; Oxygen; Pulmonary Circulation; Sheep; Vasodilation; omega-N-Methylarginine
PubMed: 8342654
DOI: 10.1152/ajpheart.1993.265.1.H376 -
Revista Espanola de Cardiologia Jan 2010
Topics: Humans; Pulmonary Circulation; Ventricular Function, Right
PubMed: 20089228
DOI: 10.1016/s1885-5857(10)70011-6 -
Annals of the New York Academy of... Sep 1965
Topics: Altitude; Animals; Cattle; Humans; Hypoxia; Pulmonary Circulation; Sheep
PubMed: 5217283
DOI: 10.1111/j.1749-6632.1965.tb49429.x -
Hang Tian Yi Xue Yu Yi Xue Gong Cheng =... Aug 2000Fluid is transferred cephalad in microgravity and simulated microgravity, and the pulmonary circulation is the first to be affected. Blood and fluid contents in the... (Comparative Study)
Comparative Study Review
Fluid is transferred cephalad in microgravity and simulated microgravity, and the pulmonary circulation is the first to be affected. Blood and fluid contents in the lungs increase, but unevenly distributed among various zones of the lungs. Blood vessels in the lungs are filled and distend. Capillary changes have been observed in the animal model of simulated microgravity. Studies about the changes of regulative function of pulmonary circulation are relatively rare. Observations of the reactivity of pulmonary vessels may help to understand the mechanisms of the changes in pulmonary circulation during microgravity.
Topics: Animals; Blood Vessels; Blood Volume; Fluid Shifts; Head-Down Tilt; Humans; Pulmonary Circulation; Space Flight; Weightlessness; Weightlessness Simulation
PubMed: 11892754
DOI: No ID Found -
Pediatric Clinics of North America Aug 1966
Topics: Blood Gas Analysis; Carbon Monoxide; Humans; Infant, Newborn; Lung; Oxygen Consumption; Pulmonary Alveoli; Pulmonary Circulation; Respiratory Function Tests
PubMed: 5946304
DOI: 10.1016/s0031-3955(16)31882-x -
Allergy and Asthma Proceedings 1996Muscular exercise presents a significant challenge to the lung and gas exchange functions of the respiratory system. The cardiovascular system is thought to be the main... (Review)
Review
Muscular exercise presents a significant challenge to the lung and gas exchange functions of the respiratory system. The cardiovascular system is thought to be the main limit to maximal exercise performance. The increase in ventilation with exercise is significant, but only in the elderly and highly fit is the pulmonary system a mechanical limit to exercise performance. Although the response in gas exchange is not perfect, the PaO2 remains preserved at the level of rest. As the oxygen delivery fails to meet the metabolic demand of the working muscle, the resultant metabolic acidosis elicits a ventilatory compensation. It is important to remember that the hemostatic and integrative nature of these organ systems can make treating each component as a discreet element very unrealistic and misleading. Muscular exercise remains a superb example of the capacity of the ventilatory/gas exchange systems to adapt to stress.
Topics: Cardiovascular Physiological Phenomena; Exercise; Humans; Pulmonary Circulation
PubMed: 8993725
DOI: 10.2500/108854196778606356 -
Respiratory Physiology & Neurobiology Aug 2002In the pulmonary circulation, a decrease in oxygen tension results in the development of hypoxic pulmonary vasoconstriction (HPV), although the exact mechanism by which... (Review)
Review
In the pulmonary circulation, a decrease in oxygen tension results in the development of hypoxic pulmonary vasoconstriction (HPV), although the exact mechanism by which HPV occurs remains unclear. Evidence gathered from many laboratories suggests that while pulmonary arterial smooth muscle cells (PASMCs) can sense and respond to changes in oxygen tension, full expression of HPV requires modulating influences from the endothelium. In this review, we propose a model of HPV, based on recent studies from our laboratory, in which endothelin-1 (ET-1), a vasoactive peptide released from the endothelium, plays a central role and discuss how this model may be involved in the long-term adaptation to hypoxia.
Topics: Acute Disease; Animals; Chronic Disease; Endothelin-1; Hypoxia; Pulmonary Circulation; Vasoconstriction
PubMed: 12126698
DOI: 10.1016/s1569-9048(02)00052-6 -
Protoplasma May 2020The present study intended to describe in detail the several blood vessels harboring special regulatory devices in rabbit's pulmonary tissue using light and electron...
The present study intended to describe in detail the several blood vessels harboring special regulatory devices in rabbit's pulmonary tissue using light and electron microscopy and immuno-histochemistry. Numerous throttle arteries were recorded within the adventitia of the segmental and sub-segmental bronchi and within pulmonary pleura. These arteries showed characteristic narrow or obliterated lumens and some of them bear longitudinal muscular intimal bolsters. For the first time, TEM revealed some structural modifications of the vascular endothelial cells of these arteries indicating that they become more activated to perform some additional functions. Arteriovenous anastomoses (AVAs) including direct shunt vessels and glomus organs were also recognized. Direct arteriovenous shunts appeared as small connecting devices communicating between small arteries and small veins while glomus organs consisted of the tortuous glomus vessels and the related afferent and efferent vessels. Several arteries and veins showing unique unusual structural characteristics were also described. For the first time, serotonin (5-HT) was strongly expressed in the vascular endothelium and muscle fibers of throttle arteries, in glomus cells of the glomus vessels, and in vascular endothelium of some veins and venules of special structure. The exact role of 5-HT is still unknown and further investigations are required to determine the types and distribution of 5-HT receptors present in these vascular devices. We concluded that these special vascular devices can play a critical role in controlling blood flow and pressure in the peripheral pulmonary circulation; however, the exact physiological mechanisms by which they work or are controlled remain unknown providing a ripe area for further investigation.
Topics: Animals; Male; Models, Animal; Pulmonary Circulation; Rabbits
PubMed: 31873814
DOI: 10.1007/s00709-019-01459-y -
American Journal of Physiology. Lung... Jan 2005
Topics: Animals; Blood Vessels; Humans; Pulmonary Circulation; Respiratory Physiological Phenomena; Stress, Mechanical
PubMed: 15591038
DOI: 10.1152/classicessays.00013.2004