Linked Life Data

10974417

Source:http://linkedlifedata.com/resource/pubmed/id/10974417

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-9-22
pubmed:abstractText
Catecholamines induce direct vasoconstriction mediated by postsynaptic alpha-adrenergic receptors (alpha-ARs) of both the alpha(1) and alpha(2) type. To evaluate the contribution of each alpha(2)-AR subtype (alpha(2A), alpha(2B), and alpha(2C)) to this function, we used groups of genetically engineered mice deficient for the gene to each one of these subtypes and compared their blood pressure (BP) responses to their wild-type counterparts. Blood pressure responses to a bolus of norepinephrine (NE) were assessed before and after sequential blockade of alpha(1)-ARs with prazosin and alpha(2)-ARs with yohimbine. The first NE bolus elicited a brief 32 to 44 mm Hg BP rise (p < 0.001 from baseline) in all six groups. Prazosin decreased BP by 23 to 33 mm Hg in all groups, establishing a new lower baseline. Repeat NE at that point elicited lesser but still significant (p < 0.001) brief pressor responses between 32% and 45% of the previous BP rise in five of the six groups. Only the alpha(2A)-AR gene knockouts differed, responding instead with a 20-mm Hg fall in BP, a significant change from baseline (p < 0.001) and different from the pressor response of their wild-type counterparts (p < 0.001). The addition of yohimbine produced no further BP change in the five groups, but it did produce a small 7. 5-mm Hg fall (p < 0.05) in the alpha(2A)-AR knockouts. Norepinephrine bolus during concurrent alpha(1) and alpha(2)-AR blockade produced significant (p < 0.001) hypotensive responses in all subgroups, presumably attributable to unopposed stimulation of beta(2)-vascular wall ARs. We conclude that the alpha(2)-AR-mediated vasoconstriction induced by catecholamines is attributable to the alpha(2A)-AR subtype because mice deficient in any one of the other subtypes retained the capacity for normal vasoconstrictive responses. However, the alpha(1)-ARs account for the major part (as much as 68%) of catecholamine-induced vasoconstriction.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0306-3623
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
101-6
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Role of the postsynaptic alpha(2)-adrenergic receptor subtypes in catecholamine-induced vasoconstriction.
pubmed:affiliation
Hypertension and Atherosclerosis Section, Department of Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.