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Prolonged lobar hypoxia in vivo enhances the responsivity of isolated pulmonary veins to hypoxiaThe hypoxic response of pulmonary vessels isolated from eight sheep whose right apical lobes (RAL) had inspired 100% N2 for 20 h was studied. The RAL of these conscious sheep inspired hypoxic gas and the remainder of the lung inspired air. During hypoxia, RAL perfusion was 33 +/- 3% of its air value, carotid arterial PO2 averaged 86 +/- 3 mm Hg and pulmonary perfusion pressure was not significantly different from the initial control period when the RAL inspired air. At the end of the hypoxic exposure, the sheep were killed, and pulmonary artery and vein rings (0.5 to 2 mm inner diameter) were isolated from both the RAL and the right cardiac lobe, which served as the control lobe (CL). Arteries from the RAL and CL did not contract in response to 6% O2/6% CO2/88% N2 (hypoxia). In contrast, RAL veins did contract vigorously in response to hypoxia, whereas CL veins did not contract or contracted only minimally. Rubbing of the endothelium or prior incubation of RAL veins with catalase (1,200 units/ml), indomethacin (10(-5) M), or the thromboxane A2/prostaglandin H2 (TxA2/PGH2) receptor antagonist, SQ 29,548 (3 X 10(-6) M) each significantly reduced the response to hypoxia. RAL veins were also found to be more reactive than CL veins to the prostaglandin endoperoxide analogue U46619. We conclude that prolonged lobar hypoxia in vivo increases the responsivity of isolated pulmonary veins to hypoxia. These contractions may result from an increase in reactive O2 species, which in turn modify production of, metabolism of, and/or tissue responsivity to TxA2/PGH2.
Document ID
20050000758
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Sheehan, D. W.
(School of Medicine and Biomedical Sciences, State University of New York Buffalo 14214)
Farhi, L. E.
Russell, J. A.
Date Acquired
August 22, 2013
Publication Date
March 1, 1992
Publication Information
Publication: The American review of respiratory disease
Volume: 145
Issue: 3
ISSN: 0003-0805
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: HL-34323
CONTRACT_GRANT: HL-28669
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cardiopulmonary
Non-NASA Center

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