Three-week neonatal hypoxia reduces blood CGRP and causes persistent pulmonary hypertension in rats
1 Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin 53706; and 2 Section of Experimental Neuroscience, Institute of Clinical Neuroscience, University of Göteborg, Mölndal's Hospital, S-43180 Mölndal, Sweden To increase understand...
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Published in | American journal of physiology. Heart and circulatory physiology Vol. 279; no. 4; pp. H1571 - H1578 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.10.2000
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Subjects | |
Online Access | Get full text |
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Summary: | 1 Department of Comparative Biosciences, School of
Veterinary Medicine, University of Wisconsin, Madison, Wisconsin 53706;
and 2 Section of Experimental Neuroscience, Institute of
Clinical Neuroscience, University of Göteborg, Mölndal's
Hospital, S-43180 Mölndal, Sweden
To increase understanding of
persistent pulmonary hypertension, we examined chronic pulmonary
effects of hypoxia at birth and their relationships with
immunoreactive levels of the potent vasodilator, calcitonin
gene-related peptide (CGRP). Rats were born in 10% hypobaric hypoxia,
where they remained for 1-2 days, or in 15% hypoxia, where they
remained for 21 days. All were then reared in normoxia for 3 mo
followed by reexposure to 10% hypoxia for 7 days (H H) or continued
normoxia (H N); age-matched normoxic rats were hypoxic for the last 7 days (N H) or normoxic throughout (N N). Results are as follows.
Pulmonary arterial pressure (P PA ) in 10% H N rats was
normal at the end of the experiment (13 wk), but in rats reexposed to
hypoxia (H H), pressure rose to 19% above N H controls. In 15%
H N rats, P PA remained high, similar to that of N H
rats, and increased further by 40% on reexposure (H H). Medial
thickness of small pulmonary arteries in 10% H H rats also increased
by 40% over N H controls and was equally high in 15% H N and
H H rats. In N H rats from both experiments, right ventricular hypertrophy index (RVH) was increased after hypoxia at 15-16 wk. Also, in the 15% study, RVH remained elevated in H N rats and increased in H H rats by 19% above N H controls. Blood CGRP was reduced by neonate and adult hypoxia, and hypoxic reexposure (H H) further lowered blood CGRP in the 15% but not 10% study. Declining left ventricular blood CGRP correlated highly with logarithmically increasing P PA in the 15% study ( r = 0.81, P = 0.000). In conclusion, 1 ) short
perinatal exposure to 10% O 2 exacerbated pulmonary
hypertension with hypoxia later in life, 2 ) 15%
O 2 at birth and for 21 days caused persistent pulmonary
hypertension and exacerbation with reexposure, and 3 )
P PA correlated highly with declining blood CGRP levels in
the 15% study.
hypoxic sensitization; persistent hyperventilation; right
ventricular hypertrophy; calcitonin gene-related peptide |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0363-6135 1522-1539 |
DOI: | 10.1152/ajpheart.2000.279.4.h1571 |