Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1982-9-24
pubmed:abstractText
Platelet-activating factor (PAF-acether), a known platelet stimulant and bronchoconstrictor (in vivo), is a potential mediator of inflammation and thrombosis. However, all smooth muscle effects of PAF-acether described to date are indirect, relying upon intravascular platelet activation. Novel actions of PAF-acether and serotonin (5-HT) are presented here; these actions may lead to the development of a practical bioassay for PAF-acether and contribute to the understanding of the mechanism of action for both substances. PAF-acether, when added to a spiral cut guinea-pig trachea suspended in a tissue bath containing Krebs-Henseleit buffer, produced a dose-dependent loss of active tissue tension. The ED50 for this effect of PAF-acether was 75 ng/ml. PAF-acether produced a maximal relaxation which was 68% of that produced by PGE1 and the effect could not be modified by aspirin or propranolol pretreatment. 5-HT, alone, contracted the guinea-pig trachea strip in a dose-dependent manner, but caused relaxation instead when methysergide was present. Aspirin, phenoxybenzamine and propranolol did not alter this loss of active tissue tension. A similar observation was made in vivo using the guinea-pig bronchoconstriction model, in which PAF-acether as well as 5-HT given to methysergide-treated animals caused a decrease in intratracheal pressure. This action of PAF-acether may yield a suitable bioassay method which could facilitate routine measurements of the substance. Furthermore, the similarity in action of PAF-acether and of 5-HT on methysergide-treated animals leads one to speculate about the relationship between the two substances and their mechanism of action in smooth muscle.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
80
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
29-35
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Relaxation of the guinea-pig trachea induced by platelet-activating factor and by serotonin.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't