Angiotensin Ii receptor subtypes involved in the modulation of purinergic and adrenergic vasoconstrictions to periarterial electrical nerve stimulation in the canine splenic artery
Yang, X.-P.; Chiba, S.
Journal of Cardiovascular Pharmacology 41(Suppl 1): S49-S52
2003
ISSN/ISBN: 0160-2446 PMID: 12688396 Document Number: 556658
Previous experiments demonstrated that periarterial electrical nerve stimulation induced a double-peaked vasoconstriction consisting of an initial transient, predominantly P2X-purinoceptor-mediated, constriction followed by a prolonged, mainly alpha1-adrenoceptor-mediated, response in the canine splenic artery. Angiotensin II at a concentration of 0.1 nM did not affect the basal vascular tone and vasoconstrictions to exogenously administered noradrenaline (0.03-3 nmol) and adenosine 5'-triphosphate (0.01-1 micromol), but it markedly potentiated the double-peaked responses to nerve stimulation. The potentiating effect of angiotensin II was inhibited by KRH-594 (10 nM), a selective angiotensin II type 1 receptor antagonist, but was not influenced by PD123319 (0.01-0.1 microM), a selective angiotensin II type 2 receptor antagonist. The results indicate that angiotensin II potentiates sympathetic purinergic and adrenergic vasoconstrictions through the prejunctional angiotensin II type 1 receptor subtype in the canine splenic artery.