Effect of aminophylline on regional perfusion distribution in the lungs.
Using ten normal dogs, the right upper lobe of the lung was isolated in vivo by a balloon catheter and was artificially ventilated with nitrogen, air, 60% oxygen in nitrogen, and 60% oxygen and 20% carbon dioxide in nitrogen, while the rest of the lungs maintained a spontaneous breathing of ambient air. Aminophylline did not show a vasodilating action under severe alveolar hypoxia (PAO2: ca. 40 mmHg); on the contrary, it seemed to potentiate hypoxic pulmonary vasoconstriction. When the regional alveolar oxygen tension became less hypoxic (PAO2: ca. 70 mmHg) or higher than that in the rest of the lungs which spontaneously breathed ambient air, aminophylline showed a definite vasodilating action. Aminophylline also showed a vasodilating action in alveolar hypercapnia in the presence of alveolar hyperoxia.
D000628:Aminophylline / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D006935:Hypercapnia / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D014664:Vasodilation; D014692:Ventilation-Perfusion Ratio / Q000187:drug effects
D000628:Aminophylline; D010100:Oxygen