The role of adenosine in hypoxic pulmonary vasoconstriction in the anaesthetized rat.
In nine artificially ventilated rats anaesthetized with Saffan, systemic hypoxia induced a tachycardia followed by a bradycardia, a fall in systemic arterial pressure and an increase in pulmonary artery pressure (PPA) indicating pulmonary vasoconstriction. This increase in PPA was abolished by the adenosine receptor antagonist 8-phenyltheophylline (8-PT, 10 mg kg-1 I.V.). Further, in seven rats the Pa,O2 achieved during hypoxia was greater after 8-PT than before (38 vs. 40 mmHg). We suggest that adenosine makes a major contribution to hypoxia-induced pulmonary vasoconstriction in the rat. The better maintenance of Pa,O2 during hypoxia may reflect improved perfusion of well-ventilated alveoli.
Thomas
T
T
Department of Physiology, Medical School, University of Brimingham.
Marshall
J M
JM
D000241:Adenosine / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D000860:Hypoxia / Q000503:physiopathology*; D008168:Lung / Q000098:blood supply* / Q000502:physiology; D011651:Pulmonary Artery / Q000502:physiology; D011667:Pulmonary Veins / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D014474:Unconsciousness / Q000503:physiopathology*; D014661:Vasoconstriction / Q000502:physiology*
D013806:Theophylline; C028322:8-phenyltheophylline; D000241:Adenosine