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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1999-11-4
pubmed:abstractText
We examined nitric oxide mediated regulation of pulmonary arterial and venous smooth muscle (PASM and PVSM, respectively): whether this inhibition is mediated via prejunctional receptors on adrenergic nerve endings; whether NO is neuronally derived; the relationship between degree of inhibition and vessel size; and identification of the signalling mechanisms involved. Canine pulmonary vascular tissues were generally quiescent, while human PASM exhibited spontaneous phasic activity. The nitric oxide (NO) synthesis inhibitor Nomega-nitro-L-arginine (L-NNA; 10(-4) M) increased tone and enhanced phasic activity. Electrical field stimulation (EFS) evoked contractions were markedly enhanced by L-NNA in an endothelium-dependent fashion, and antagonized by the NO donor S-nitroso-N-acetylpenicillamine (SNAP; 10(-7) to 10(-5) M). 8-Bromo-cGMP mimicked the effects of SNAP on basal tone and EFS contractions, while an inhibitor of soluble guanylate cyclase mimicked those of L-NNA. While mechanical responses to exogenously added norepinephrine (10(-9)-10(-4) M) were also enhanced by L-NNA and suppressed by SNAP, EFS-evoked excitatory junction potentials were unaffected by SNAP. We conclude that, in human and canine PASM and PVSM, there is a tonic generation of NO originating within the endothelium that does not mediate a prejunctional effect, but which acts postjunctionally to activate a cGMP-dependent pathway within the smooth muscle.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0008-4212
pubmed:author
pubmed:issnType
Print
pubmed:volume
77
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
320-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Nitric oxide inhibits human and canine pulmonary vascular tone via a postjunctional, nonelectromechanical, cGMP-dependent pathway.
pubmed:affiliation
Department of Medicine, McMaster University, Hamilton, ON, Canada. janssenl@fhs.csu.mcmaster.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't