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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10-11
pubmed:dateCreated
1997-2-19
pubmed:abstractText
1. The haemodynamic mechanisms by which infusion of angiotensin II (AngII), either into the lateral cerebral ventricles (i.c.v.) or intravenously (i.v.), increased arterial pressure were studied in conscious sheep. 2. Sheep were previously fitted with flow probes for measurement of cardiac output and coronary, mesenteric, renal and iliac blood flows. 3. Intracerebroventricular AngII (10 nmol/h for 1 h) increased arterial pressure by 11 +/- 4 mmHg (P < 0.001) due to vasoconstriction, predominantly in the mesentric vasculature. These effects developed over 30 min and took 2 h to return to control. Following the infusion renal conductance increased continuously for 3 h, resulting in a parallel increase in renal blood flow (to 75 +/- 18 mL/min above control, P < 0.001). 4. Intracerebroventricular AngII increased plasma vasopressin from 0.8 +/- 0.3 to 7.2 +/- 1.8 pg/mL (P, 0.01), and reduced plasma renin concentration from 0.9 +/- 0.3 to < 0.4 nmol/L/h. 5. The pressor effect of i.v. AngII (5, 10, 25, 50 nmol/h) also depended on peripheral vasoconstriction, but the pattern of responses was different. The greatest degree of vasoconstriction occurred in the renal, followed by the mesentric and iliac vascular beds; these effects were rapid in onset and offset. 6. In conclusion, the pressor responses to both i.c.v. and i.v. angiotensin depended on peripheral vasoconstriction, but there were contrasting regional haemodynamic changes. ICV AngII caused a prolonged pressor response, mainly due to mesentric vasoconstriction possibly partly due to vasopressin release, and following the infusion there was a pronounced, long-lasting renal vasodilatation. In contrast, i.v. AngII caused vasoconstriction preferentially in the renal vascular bed and its effects were short lasting.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0305-1870
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
878-84
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:articleTitle
Prolonged systemic and regional haemodynamic effects of intracerebroventricular angiotensin II in conscious sheep.
pubmed:affiliation
Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't