Linked Life Data

12855052

Source:http://linkedlifedata.com/resource/pubmed/id/12855052

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2003-7-11
pubmed:abstractText
In response to high altitude long-term hypoxemia, the heart of fetal sheep shows a decrease in cardiac output that is secondary to a decrease in myocardial cell contractile function. The intracellular mechanisms responsible for these reductions might include reduced myofibrillar Mg(2+)-activated ATPase. There is also a decrease in beta(1)-adrenergic receptor stimulated augmentation of myocardial contraction. An overproduction of cAMP by beta(1)-adrenergic receptor stimulation, resulting in overphosphorylation of troponin I, may reduce calcium binding by troponin C. Fetal coronary arteries have a reduced contractile response to K(+) depolarization and a reduced sensitivity to a thromboxane A(2) receptor agonist-stimulated contraction. Cerebral arteries of adult sheep (but not the fetus) show decreased responses to both K(+)-depolarization and norepinephrine-induced contraction. Nonetheless, cerebral arteries in the long-term hypoxic fetus demonstrated a number of significant changes from control. For the cerebral arteries in general, high altitude hypoxia is associated with augmented or upregulation of presynaptic functions. In contrast, postsynaptic functions tend to be significantly depressed or downregulated. The results emphasize the role of high altitude, long-term hypoxemia in modulating adrenergic- and serotonergic-mediated signal transduction in the cerebral vasculature. They specifically highlight the significant differences in acclimatization responses between the fetus and adult.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
1527-0297
pubmed:author
pubmed:issnType
Print
pubmed:volume
4
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
203-13
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Fetal cardiac and cerebrovascular acclimatization responses to high altitude, long-term hypoxia.
pubmed:affiliation
Departments of Physiology and Pharmacology, Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, USA. rgilbert@som.llu.edu
pubmed:publicationType
Journal Article, Review