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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-2-9
pubmed:abstractText
Angiotensin II increases afferent discharge from the carotid body in vitro. We hypothesized that angiotensin II receptors (AT receptors) are expressed functionally in the type-I cell of the carotid body. Cytosolic free [Ca2+] ([Ca2+]i) in type-I cells freshly dissociated from rat carotid bodies was measured spectrofluorimetrically. Angiotensin II (10-100 nM) concentration-dependently increased [Ca2+]i in type-I cells. The [Ca2+]i response was blocked by pretreatment with losartan (1 microM), an AT1 receptor antagonist, but not by blockade of AT2 receptors with PD- 123319 (1 microM). Moreover, the gene expression of AT1 receptors was assessed by the reverse transcriptase polymerase chain reaction and gene transcripts of both AT1a and AT1b receptors were detected in the carotid body. In addition, immunohistochemical study revealed that AT1 immunoreactivity was localized in lobules of type-I cells in the carotid body. Taken together, these results suggest that type-I cells in the rat carotid body express functional angiotensin II receptors. The binding of angiotensin II to the AT1 receptors increases [Ca2+]i, a key step of the intracellular signalling cascade following the activation of the receptors. It is concluded that angiotensin II modulates carotid body chemoreceptor function directly via AT1 receptors in the type-I cell.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
441
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
474-80
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:11212210-Angiotensin II, pubmed-meshheading:11212210-Angiotensin Receptor Antagonists, pubmed-meshheading:11212210-Animals, pubmed-meshheading:11212210-Calcium, pubmed-meshheading:11212210-Carotid Body, pubmed-meshheading:11212210-Gene Expression, pubmed-meshheading:11212210-Imidazoles, pubmed-meshheading:11212210-Immunohistochemistry, pubmed-meshheading:11212210-Losartan, pubmed-meshheading:11212210-Pyridines, pubmed-meshheading:11212210-RNA, Messenger, pubmed-meshheading:11212210-Rats, pubmed-meshheading:11212210-Rats, Sprague-Dawley, pubmed-meshheading:11212210-Receptor, Angiotensin, Type 1, pubmed-meshheading:11212210-Receptor, Angiotensin, Type 2, pubmed-meshheading:11212210-Receptors, Angiotensin, pubmed-meshheading:11212210-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:11212210-Spectrometry, Fluorescence
pubmed:year
2001
pubmed:articleTitle
Functional expression of angiotensin II receptors in type-I cells of the rat carotid body.
pubmed:affiliation
Department of Physiology and Institute of Cardiovascular Science and Medicine, Faculty of Medicine, University of Hong Kong, Pokfulam, SAR. fungml@hkucc.hku.hk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't