Linked Life Data

1677038

Source:http://linkedlifedata.com/resource/pubmed/id/1677038

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1991-8-20
pubmed:abstractText
Fenoldopam [6-chloro-7,8-dihydroxy-1-(4'-hydroxyphenyl)-2, 3,4,5-tetrahydro-(1H)-3-benzazepine] is a selective dopamine-1 (DA1) agonist with natriuretic/diuretic properties. A component of the natriuretic response to fenoldopam may involve direct DA1 receptor-mediated effects on proximal tubule sodium reabsorption, possibly through stimulation of adenylyl cyclase. Here, we compared the effects of fenoldopam and DA in stimulating cyclic AMP (cAMP) synthesis in LLC-PK1 cells, a renal epithelial cell line that has proximal tubule-like properties and expresses a DA1 receptor linked to stimulation of adenylyl cyclase. Fenoldopam stimulated cAMP accumulation in LLC-PK1 cells in a dose-dependent manner, an effect which could be blocked by the DA1-selective antagonist Sch 23390. Although fenoldopam was more potent than DA (EC50 55.5 +/- 7.75 nM vs. 1.65 +/- 0.64 microM) in stimulating cAMP accumulation in LLC-PK1 cells, the maximum stimulation obtained by fenoldopam was only 37% of the maximum stimulation obtained by DA(Emax 13.0 +/- 2.95 pmol/mg of protein vs. 35.6 +/- 10.19 pmol/mg of protein). Simultaneous incubation of DA and fenoldopam resulted in lower cAMP levels than with DA alone. Incubation of DA with increasing concentrations of fenoldopam produced parallel rightward shifts in the DA dose-response curves. Schild analysis further indicated that fenoldopam acted as a competitive antagonist in the presence of DA, with a pA2 value of 7.38 and a slope of unity. These results indicate that fenoldopam is a partial agonist with low efficacy at DA1 receptors linked to cAMP generation in the LLC-PK1 cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
193-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Fenoldopam is a partial agonist at dopamine-1 (DA1) receptors in LLC-PK1 cells.
pubmed:affiliation
Department of Pharmacology, Mount Sinai School of Medicine, City University of New York, New York.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't