The role of angiotensin II in hypertension due to adenosine receptors blockade.
The renin-angiotensin system may be involved in hypertension induced by adenosine receptors blockade with 1,3-dipropyl-8-sulfophenylxanthine (DPSPX). Contractions of the mesenteric vasculature to angiotensin II, noradrenaline and potassium chloride were studied in DPSPX-induced hypertension. Male Wistar rats received infusions of saline or DPSPX (90 microg kg(-1) h(-1), i.p.) for 3 or 7 days. Blood pressure was determined by the tail-cuff method. On days 3 or 14, concentration-response curves were obtained on mesenteric arteries and veins. Plasma angiotensin II levels, measured by radioimmunoassay, were higher in DPSPX-hypertensive rats. The maximum contractile effect of angiotensin II was lower in vessels from DPSPX-hypertensive rats while that for noradrenaline was higher. Potassium chloride-induced contractions were larger in veins from DPSPX-hypertensive rats but similar in arteries, when compared with control rats. We conclude that raised angiotensin II levels and altered vascular reactivity are consistent with a renin-angiotensin-mediated hypertension.
Morato
Manuela
M
Institute of Pharmacology and Therapeutics, Faculty of Medicine of Porto and IBMC, University of Porto, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal.
Sousa
Teresa
T
Guimarães
Serafim
S
Moura
Daniel
D
Albino-Teixeira
António
A
D000804:Angiotensin II / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000503:physiopathology; D008642:Mesenteric Veins / Q000187:drug effects / Q000503:physiopathology; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
D058915:Purinergic P1 Receptor Antagonists; D014662:Vasoconstrictor Agents; D014970:Xanthines; D000804:Angiotensin II; D011189:Potassium Chloride; C053896:1,3-dipropyl-8-(4-sulfophenyl)xanthine; D009638:Norepinephrine