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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2000-5-9
pubmed:abstractText
Increasing renal arterial pressure activates at least 3 antihypertensive mechanisms: reduced renin release, pressure natriuresis, and release of a putative renal medullary depressor hormone. To examine the role of renal medullary perfusion in these mechanisms, we tested the effects of the infusion of norepinephrine, either infusion into the renal medullary interstitium or intravenous infusion, on responses to increased renal arterial pressure in pentobarbital-anesthetized rabbits. We used an extracorporeal circuit, which allows renal arterial pressure to be set to any level above or below systemic arterial pressure. With renal arterial pressure initially set at 65 mm Hg, intravenous and medullary interstitial norepinephrine (300 ng. kg(-1). min(-1)) similarly increased mean arterial pressure (by 12% to 17% of baseline) and reduced total renal blood flow (by 16% to 17%) and cortical perfusion (by 13% to 19%), but only medullary norepinephrine reduced medullary perfusion (by 28%). When renal arterial pressure was increased to approximately 160 mm Hg, in steps of approximately 65 mm Hg, urine output and sodium excretion increased exponentially, and plasma renin activity and mean arterial pressure fell. Medullary interstitial but not intravenous norepinephrine attenuated the increased diuresis and natriuresis and the depressor response to increased renal arterial pressure. This suggests that norepinephrine can act within the renal medulla to inhibit these renal antihypertensive mechanisms, perhaps by reducing medullary perfusion. These observations support the concept that medullary perfusion plays a critical role in the long-term control of arterial pressure by its influence on pressure diuresis/natriuresis mechanisms and also by affecting the release of the putative renal medullary depressor hormone.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0194-911X
pubmed:author
pubmed:issnType
Print
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
965-70
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Effects of renal medullary and intravenous norepinephrine on renal antihypertensive function.
pubmed:affiliation
Department of Physiology, Monash University, Clayton, Victoria, Australia. anabela.correia@med.monash.edu.au
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't