Linked Life Data

8842869

Source:http://linkedlifedata.com/resource/pubmed/id/8842869

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-1-8
pubmed:abstractText
1. The mechanism of the protective action of alpha-tocopherol (vitamin E) in sustaining noradrenaline-induced responses in vascular hypoxia was investigated using pharmacological methods. 2. Four vascular spasmogenic agents, methoxamine, acetylcholine, histamine and potassium, each with a different mode of action were used to produce responses in guinea-pig isolated portal vein. In each case the responses were significantly reduced by hypoxia or hypoxia and a substrate-free environment. 3. Pre-incubation of the vein with alpha-tocopherol protected the noradrenaline-induced responses against hypoxia in the substrate-free environment, However, at the EC50 concentration for protection of noradrenaline, alpha-tocopherol failed to protect the responses of each agent from the inhibitory effects of hypoxia, suggesting a mechanism of protection involving noradrenaline. 4. Drugs known to interfere with the disposition of noradrenaline in sympathetically innervated tissues, cocaine, hydrocortisone and tyramine did not affect the response to alpha-tocopherol. 5. Responses to calcium were unaffected by alpha-tocopherol in normoxia and hypoxia. 6. The protective action of alpha-tocopherol was not mimicked by the chromanol ring of the vitamin structure, Trolox C, suggesting that the vascular protection in hypoxia was not dependent on an antioxidant mechanism. 7. However, the glycolytic enzyme inhibitor, iodoacetic acid, prevented the protective action of the vitamin in hypoxia, suggesting that alpha-tocopherol enhanced noradrenaline-mediated activity in hypoxia through an iodoacetic acid-sensitive pathway.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0144-1795
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
87-95
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Possible mechanisms for the protective action of alpha-tocopherol in vascular hypoxia.
pubmed:affiliation
Health Sciences Group, Leeds Metropolitan University, UK.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't