Blood pressure dependency on vasopressin and angiotensin II in prazosin-treated conscious normotensive rats

Details

Serval ID
serval:BIB_849803790F29
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Blood pressure dependency on vasopressin and angiotensin II in prazosin-treated conscious normotensive rats
Journal
Journal of Pharmacology and Experimental Therapeutics
Author(s)
Waeber  B., Nussberger  J., Brunner  H. R.
ISSN
0022-3565 (Print)
Publication state
Published
Issued date
05/1983
Volume
225
Number
2
Pages
442-6
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: May
Abstract
The role of the sympathetic nervous system, angiotensin II and vasopressin in limiting the hypotensive effect of prazosin (0.25 mg i.v.) was investigated in conscious normotensive rats. Within 45 min, mean blood pressure fell from 120 +/- 1 to 98 +/- 1 mm Hg (mean +/- S.E.M., P less than .001) while pulse rate rose from 463 +/- 9 to 500 +/- 9 beats/min (P less than .01). The blood pressure response to prazosin tended to be most pronounced in the rats with the smallest increase in heart rate (r = 0.58, P less than .001). Plasma norepinephrine and epinephrine levels were higher in prazosin-treated rats than in the controls (P less than .001). In the animals receiving prazosin, plasma renin activity was 4 times (P less than .001) and plasma vasopressin 7 times (P less than .01) higher than in the controls. Blockade of angiotensin II with saralasin (10 micrograms/min) further decreased blood pressure of the prazosin-treated rats by 22 +/- 4 mm Hg (P less than .001). In contrast, dPVDAVP (25 micrograms), a vasopressin antagonist, had no effect. Prazosin decreased the pressor response to methoxamine (10 micrograms) by 80% (P less than .001) but not to angiotensin II (60 ng). However, prazosin enhanced the reflex bradycardia induced by angiotensin II (P less than .001). These data demonstrate that both the sympathetic and the renin angiotensin system are markedly stimulated by prazosin; they both appear to limit its acute hypotensive action. In contrast, although plasma vasopressin is also increased, its pressor action is effectively buffered, probably due to enhanced baroreflex sensitivity.
Keywords
Angiotensin II/*pharmacology Animals Arginine Vasopressin/*pharmacology Blood Pressure/*drug effects Bradycardia/chemically induced Catecholamines/blood Deamino Arginine Vasopressin/administration & dosage Heart Rate/drug effects Male Methoxamine/pharmacology Prazosin/*administration & dosage Pressoreceptors/drug effects Quinazolines/*administration & dosage Rats Renin/blood Saralasin/administration & dosage
Pubmed
Web of science
Create date
05/03/2008 16:41
Last modification date
20/08/2019 14:44
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