Angiotensin causes vasoconstriction during hemorrhage in baroreceptor-denervated dogs.
Am J Physiol
; 245(4): H667-73, 1983 Oct.
Article
em En
| MEDLINE
| ID: mdl-6624936
ABSTRACT
The participation of angiotensin II (ANG II) in the maintenance of arterial blood pressure during hypotensive hemorrhage was examined in unanesthetized, baroreceptor-denervated dogs. When mean aortic blood pressure was reduced to 69.0 +/- 2.2 mmHg, plasma renin activity increased from 0.6 +/- 0.3 ng ANG I X ml-1 X h-1 during the prehemorrhage control period to 4.5 +/- 1.6. Twenty minutes after the hemorrhage, mean aortic blood pressure rose to 78.9 +/- 3.1 mmHg. Subsequent infusion of the angiotensin II antagonist saralasin (5.2-14.0 micrograms X kg-1 X min-1) decreased mean aortic pressure to 59.6 +/- 3.3 mmHg. When 5% dextrose was infused in place of saralasin, mean aortic pressure was 79.3 +/- 4.3 mmHg. The lower aortic blood pressure caused by saralasin infusion was the result of a significant decrease in total peripheral resistance. Resistance was 10.3 +/- 3.2 mmHg X l-1 X min lower during saralasin infusion than during dextrose infusion. We conclude that baroreceptor reflexes are not essential for the elevation of plasma renin activity during hemorrhage. In baroreceptor-denervated dogs subjected to hypotensive hemorrhage, the increased formation of ANG II has a vasoconstrictor action that contributes to the maintenance of arterial blood pressure.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aorta
/
Pressorreceptores
/
Vasoconstrição
/
Angiotensina II
/
Seio Carotídeo
/
Hemorragia
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol
Ano de publicação:
1983
Tipo de documento:
Article