title: Pre- and postjunctional effects of angiotensin II in hypertension due to adenosine receptor blockade.
abstract: Prejunctional facilitation of [3H]noradrenaline release induced by sympathetic nerve stimulation and postjunctional contractile effects of angiotensin II were studied in the mesenteric artery and vein of 1,3-dipropyl-8-sulfophenylxanthine (DPSPX)-hypertensive rats. Male Wistar rats received infusions of saline or DPSPX (90 microg/kg/h) i.p.. Blood pressure was determined by tail-cuff. The prejunctional effect of angiotensin II was similar in artery and vein preparations of control rats and was increased in DPSPX-hypertensive rats. In contrast, the contractile effect of angiotensin II was much more pronounced in the mesenteric vein than in the mesenteric artery of control rats and was markedly reduced in DPSPX-hypertensive rats. We conclude that (1) the increased prejunctional effect of angiotensin II may contribute to, while (2) the decreased contractile effect of angiotensin II may attenuate DPSPX-induced hypertension. This study also supports the hypothesis that pre- and postjunctional angiotensin II receptors are different.
authors.affiliation: Institute of Pharmacology and Therapeutics, Faculty of Medicine and IBMC, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal.
authors.forename: Manuela
authors.initials: M
authors.lastname: Morato
authors.forename: Dora
authors.initials: D
authors.lastname: Pinho
authors.forename: Teresa
authors.initials: T
authors.lastname: Sousa
authors.forename: Serafim
authors.initials: S
authors.lastname: Guimarães
authors.forename: Daniel
authors.initials: D
authors.lastname: Moura
authors.forename: António
authors.initials: A
authors.lastname: Albino-Teixeira
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology; D008642:Mesenteric Veins / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology; D009638:Norepinephrine / Q000378:metabolism; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017208:Rats, Wistar; D018047:Receptors, Purinergic P1 / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014970:Xanthines / Q000008:administration & dosage / Q000633:toxicity
chemical_list: D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1; D014662:Vasoconstrictor Agents; D014970:Xanthines; D000804:Angiotensin II; C053896:1,3-dipropyl-8-(4-sulfophenyl)xanthine; D009638:Norepinephrine