Linked Life Data

12623951

Source:http://linkedlifedata.com/resource/pubmed/id/12623951

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-3-7
pubmed:abstractText
Marinobufagenin (MBG), an endogenous ligand of alpha-1 Na/K-ATPase, becomes elevated and contributes to hypertension in NaCl-loaded Dahl-S rats (DS). Protein kinase C (PKC) phosphorylates alpha-1 Na/K-ATPase and increases its MBG sensitivity. Cicletanine, an antihypertensive compound with PKC-inhibitory activity, reverses MBG-induced Na/K-ATPase inhibition and vasoconstriction. We hypothesized that increased PKC levels in sodium-loaded hypertensive DS would sensitize alpha-1 Na/K-ATPase to MBG and that PKC inhibition by cicletanine would produce an opposite effect. We studied the effects of cicletanine on systolic blood pressure, left ventricular PKC isoforms, cardiac alpha-1 Na/K-ATPase levels, and sensitivity to MBG in hypertensive DS. Seven DS received 50 mg x kg(-1) x d(-1) cicletanine, and 7 DS received vehicle during 4 weeks of an 8% NaCl diet. Vehicle-treated rats exhibited an increase in blood pressure, left ventricular mass, MBG excretion (74+/-11 vs 9+/-1 pmol/24 h, P<0.01), myocardial alpha-1 Na/K-ATPase protein, and PKC beta2 and delta. The sensitivity of Na/K-ATPase to MBG was enhanced at the level of high-affinity binding sites (IC50, 0.8 vs 4.4 nmol/L, P<0.01). Cicletanine-treated rats exhibited a 56-mm Hg reduction in blood pressure (P<0.01) and a 30% reduction in left ventricular weight, whereas cardiac alpha-1 Na/K-ATPase protein and MBG levels were unchanged. In cicletanine-treated rats, PKC beta2 was not increased, the sensitivity of Na/K-ATPase to MBG was decreased (IC50=20 micromol/L), and phorbol diacetate-induced alpha-1 Na/K-ATPase phosphorylation was reduced versus vehicle-treated rats. In vitro cicletanine treatment of sarcolemma from vehicle-treated rats also desensitized Na/K-ATPase to MBG, indicating that this effect was not solely attributable to a reduction in blood pressure. Thus, PKC-induced phosphorylation of cardiac alpha-1 Na/K-ATPase is a likely target for cicletanine treatment.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1524-4563
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
505-11
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Myocardial PKC beta2 and the sensitivity of Na/K-ATPase to marinobufagenin are reduced by cicletanine in Dahl hypertension.
pubmed:affiliation
Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institutes of Health, 5600 Nathan Shock Dr, Baltimore, MD 21224, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't