Linked Life Data

9277588

Source:http://linkedlifedata.com/resource/pubmed/id/9277588

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2 Pt 2
pubmed:dateCreated
1997-9-25
pubmed:abstractText
Activation of angiotensin receptors activates phospholipase A2 (PLA2) in various tissues, resulting in the release of arachidonic acid and formation of vasoactive metabolites. The present study examined the role of the lipoxygenase and cytochrome P-450 pathways by evaluating the effects of PLA2, cyclooxygenase, lipoxygenase, and epoxygenase inhibition on the afferent arteriolar responses to angiotensin II (ANG II) and norepinephrine in the vitro perfused rat juxtamedullary nephron preparation. ANG II (0.01-100 nM) resulted in a dose-dependent afferent arteriolar vasoconstriction ranging from 3 +/- 1 to 32 +/- 2% (n = 47). Norepinephrine at 0.01, 0.1, and 1.0 microM also decreased afferent arteriolar diameter by 5 +/- 1, 17 +/- 1, and 34 +/- 2%, respectively (n = 43). In the presence of arachidonyl trifluoromethyl ketone (AACOCF3, 20 microM), a PLA2 inhibitor, afferent arteriolar vasoconstriction to ANG II (100 nM) was attenuated, and the diameter decreased by 23 +/- 4% (n = 7). The cyclooxygenase inhibitor, indomethacin (10 microM), and the cyclooxygenase-2 inhibitor, NS-398 (10 microM), did not affect the afferent arteriolar response to ANG II. The lipoxygenase inhibitor biacalein (1 microM) attenuated the afferent arteriolar response to ANG II, and vessel diameter decreased by 11 +/- 5% (n = 6) in response to 100 nM ANG II. On the other hand, miconazole (1 microM), a selective epoxygenase inhibitor, enhanced the afferent arteriolar vasoconstriction to 100 nM ANG II. 17-Octadecynoic acid (17-ODYA, 1 microM), an inhibitor of hydroxylase and epoxygenase metabolism of arachidonic acid, also increased the responsiveness of the afferent arteriole. PLA2, lipoxygenase, or cytochrome P-450 inhibition had no effect on the afferent arteriolar vasoconstriction to norepinephrine. The afferent arteriolar vasoconstrictor response to norepinephrine (0.1 microM) was enhanced by indomethacin or NS-398, and diameter decreased by 25 +/- 3% and 28 +/- 4%, respectively. Results of this study suggest that metabolites of the cyclooxygenase pathway attenuate the afferent arteriolar vasoconstrictor effect of norepinephrine. Furthermore, these data suggest that activation of PLA2 is involved in part of the afferent arteriolar response to ANG II and that metabolites of the lipoxygenase pathway augment and metabolites of the epoxygenase pathway attenuate the afferent arteriolar vasoconstrictor effect of ANG II.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
F274-82
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Afferent arteriolar responses to ANG II involve activation of PLA2 and modulation by lipoxygenase and P-450 pathways.
pubmed:affiliation
Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't