Navegando por Palavras-chave "angiotensin receptor"

Agora exibindo 1 - 2 de 2
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Angiotensin receptor in the heart of Bothrops jararaca snake
    (Elsevier B.V., 2001-04-06) Breno, M. C.; Porto, C. S.; Picarelli, Z. P.; Universidade Federal de São Paulo (UNIFESP); Inst Butantan
    Angiotensin II interacts with specific cell surface angiotensin AT(1) and AT(2) receptors and, in some vertebrates, with an atypical angiotensin AT receptor. This study was designed to characterize the angiotensin receptor in the heart of Bothrops jararaca snake. A specific and saturable angiotensin II binding site was detected in cardiac membranes and yielded K-d = 7.34 +/- 1.41 nM and B-max = 72.49 +/- 18 fmol/mg protein. Competition-binding studies showed an angiotensin receptor with low affinity to both angiotensin receptor antagonists, losartan (2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl)biphenyl-4-yl)methyl]imidazole) and PD123319 ((s)-1-(4-[dimethylamino]-3-methylphenyl)methyl-5-(diphenylacetyl)-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylate). Studies on the intracellular signaling pathways showed that phospholipase C/inositol phosphate breakdown and adenylylcyclase/cyclic AMP generation were not coupled with this angiotensin receptor. An adenylylcyclase enzyme sensitive to forskolin was detected. the results indicate the presence of an angiotensin receptor in the heart of B. jararaca snake pharmacologically distinct from angiotensin AT(1) and AT(2) receptors. It seems to belong to a new class of angiotensin receptors, like some other atypical angiotensin AT receptors that have already been described. (C) 2001 Elsevier Science B.V. All rights reserved.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Hemodynamic and metabolic effects of angiotensin II on the liver
    (Elsevier B.V., 2005-02-01) Nascimento, T. A.; Gioli-Pereira, L.; Carvalho, L. T.; Santos, E. L.; Pesquero, J. B.; Kouyoumdjian, M.; Borges, D. R.; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Maringá (UEM)
    To ascertain the mechanism of interaction between angiotensins (AI and AII) and the liver. an angiotensin-converting enzyme inhibitor (captopril) and a receptor antagonist (losartan) were used. Monovascular or bivascular liver perfusion was used to assess both hemodynamic (portal and arterial hypertensive responses) and metabolic (glucose production and oxygen consumption) effects. Microphysiometry was used for isolated liver cell assays to assess AII or losartan membrane receptor-mediated interaction. Captopril abolishes portal hypertensive response (PHR) to AI but not the AII effect. AII infused via the portal pathway promotes calcium-dependent PHR but not a hypertensive response in the arterial pathway (AHR); when infused into the arterial pathway AII promotes calcium-dependent PHR and AHR. Losartan infused into the portal vein abolishes PHR to AII but not the metabolic response: when infused via both pathways it abolishes the hypertensive responses and inhibits the metabolic effects. Isolated liver cells specifically respond to AII Sinusoidal cells, but not hepatocytes. respond to 10 nM losartan. We conclude that AI has to be converted to AII to produce PHR. Quiescent stellate cells interacts in vitro with AII and losartan. Hemodynamic responses to AII are losartan-dependent but metabolic responses are partially losarian-independent, AII hemodynamic actions are mainly presinusoidal. (C) 2004 Elsevier Inc. All rights reserved.