Pulmonary vascular reactivity in Fischer rats.
We previously reported that Fischer (F) rat lungs developed more extensive injury when challenged with oxidants than age-matched Sprague-Dawley (SD) rat lungs. We now describe a reduced pulmonary vascular response to alveolar hypoxia and angiotensin II (ANG II) in F compared with SD rats. The comparative studies were performed with isolated lungs perfused with salt solution or blood, catheter-implanted awake rats, and isolated main pulmonary arterial rings. Isolated lungs from F rats perfused with either blood or salt solution had reduced vasoconstriction in comparison with lungs from SD rats when exposed to alveolar hypoxia or challenged with ANG II. Instrumented awake F rats had a smaller mean increase in total pulmonary vascular resistance (PVR) than SD rats (35 vs. 94 mmHg.min.l-1, P less than 0.05) when challenged with 8% oxygen. The contractile response of isolated pulmonary artery but not thoracic aortic rings to KCl and ANG II was reduced in F compared with SD rats. In addition, F rats exposed to 4 wk of hypobaric hypoxia developed less pulmonary hypertension and right ventricular hypertrophy (when corrected for the hematocrit) than SD rats. We conclude that the oxidant stress-sensitive inbred F rat strain is characterized by a lung vascular bed that is relatively unresponsive to vasoconstricting stimuli. The mechanism underlying this genetic difference in lung vascular control remains to be defined.
He
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Cardiovascular Pulmonary Research Laboratory, University of Colorado Health Sciences Center, Denver 80262.
Chang
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SW
Voelkel
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NF
D000531:Altitude; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000860:Hypoxia / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D010477:Perfusion; D011652:Pulmonary Circulation / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D011919:Rats, Inbred Strains; D013045:Species Specificity; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology
D000804:Angiotensin II