title: Angiotensin(1-7) is an antagonist at the type 1 angiotensin II receptor.
abstract: OBJECTIVE
  The present study investigated the antagonism of the amino-terminal heptapeptide fragment of angiotensin II ([des-Phe8]-angiotensin II; Ang(1-7)) to angiotensin II (Ang II) both in vitro in rabbit aortae and in vivo in rats.
  
  
  RESULTS
  In rabbit isolated endothelium intact aortic rings Ang(1-7) caused a concentration-related rightward displacement of the Ang II curve and depressed the maximum response to Ang II. By applying the data to a Schild plot an apparent pA2 of 5.5 was calculated. This depression of maximum response could be reversed by co-incubation of Ang(1-7) with the competitive angiotensin antagonist losartan. Ang(1-7) had no effect on the contractile responses of several other agonists. Intravenous infusion of 10 or 100 micrograms/kg per min Ang(1-7) had no effect on the resting blood pressure in the anaesthetized rat but inhibited Ang II-induced pressor responses.
  
  
  CONCLUSIONS
  The present results show that Ang(1-7) is a specific non-competitive antagonist of Ang II at type 1 angiotensin II receptors.
authors.affiliation: Institute of Endocrinology, University of Sheffield, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Mahon
authors.forename: R D
authors.initials: RD
authors.lastname: Carr
authors.forename: A K
authors.initials: AK
authors.lastname: Nicol
authors.forename: I W
authors.initials: IW
authors.lastname: Henderson
mesh_terms: D000803:Angiotensin I; D000804:Angiotensin II / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001713:Biphenyl Compounds / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D019808:Losartan; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D013777:Tetrazoles / Q000494:pharmacology
chemical_list: D057911:Angiotensin Receptor Antagonists; D001713:Biphenyl Compounds; D007093:Imidazoles; D010446:Peptide Fragments; D013777:Tetrazoles; D000804:Angiotensin II; D000803:Angiotensin I; C118790:angiotensin I (1-7); D019808:Losartan