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

Détails

ID Serval
serval:BIB_849803790F29
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Blood pressure dependency on vasopressin and angiotensin II in prazosin-treated conscious normotensive rats
Périodique
Journal of Pharmacology and Experimental Therapeutics
Auteur(s)
Waeber  B., Nussberger  J., Brunner  H. R.
ISSN
0022-3565 (Print)
Statut éditorial
Publié
Date de publication
05/1983
Volume
225
Numéro
2
Pages
442-6
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: May
Résumé
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.
Mots-clé
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
Création de la notice
05/03/2008 17:41
Dernière modification de la notice
03/03/2018 18:55
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