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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2006-5-19
pubmed:abstractText
Angiotensin type 1A (AT(1A)) receptors are expressed within the rostral ventrolateral medulla, and microinjections of angiotensin II into this region increase sympathetic vasomotor tone. To determine the effect of sustained increases in AT(1A) receptor density or activity in rostral ventrolateral medulla, we used radiotelemetry to monitor blood pressure in conscious rats before and after bilateral microinjection into the rostral ventrolateral medulla of adenoviruses encoding the wild-type AT(1A) receptor or a constitutively active version of the receptor (Asn111Gly, [N111G]AT(1A)). The constitutively active receptor signals in the absence of angiotensin II. Adenovirus-directed receptor expression was extensively characterized both in vitro and in vivo. We established that adenoviral infection was limited to the rostral ventrolateral medulla and that receptor expression was sustained for > or =10 days; we also observed that adenoviral transgene expression occurs in glia, with no transgene expression observed in neurons of the rostral ventrolateral medulla. Rats receiving the wild-type AT(1A) receptor showed no change in blood pressure, whereas animals receiving the [N111G]AT(1A) receptor displayed an increase in blood pressure that persisted for 3 to 4 days before returning to basal levels. These data indicate that increased AT(1A) receptor activity (not just overexpression) is a primary determinant of efferent drive from rostral ventrolateral medulla and reveal counterregulatory processes that moderate AT(1A) receptor actions at this crucial relay point. More importantly, they imply that constitutive receptor signaling in glia of the rostral ventrolateral medulla can modulate the activity of adjacent neurons to change blood pressure.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1524-4563
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1054-61
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:16618838-Adenoviridae, pubmed-meshheading:16618838-Animals, pubmed-meshheading:16618838-Asparagine, pubmed-meshheading:16618838-Blood Pressure, pubmed-meshheading:16618838-Cell Line, pubmed-meshheading:16618838-Gene Expression, pubmed-meshheading:16618838-Gene Transfer Techniques, pubmed-meshheading:16618838-Genetic Vectors, pubmed-meshheading:16618838-Glycine, pubmed-meshheading:16618838-Humans, pubmed-meshheading:16618838-Male, pubmed-meshheading:16618838-Medulla Oblongata, pubmed-meshheading:16618838-Mutation, pubmed-meshheading:16618838-Neuroglia, pubmed-meshheading:16618838-Rats, pubmed-meshheading:16618838-Rats, Inbred WKY, pubmed-meshheading:16618838-Receptor, Angiotensin, Type 1, pubmed-meshheading:16618838-Signal Transduction, pubmed-meshheading:16618838-Time Factors, pubmed-meshheading:16618838-Transgenes
pubmed:year
2006
pubmed:articleTitle
Expression of constitutively active angiotensin receptors in the rostral ventrolateral medulla increases blood pressure.
pubmed:affiliation
Department of Physiology, University of Melbourne, Victoria, Australia. a.allen@unimelb.edu.au
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't