title: Comparison of blood pressure responses to intra-arterial and intra-venous injections of angiotensin I, angiotensin II and bradykinin.
abstract: Because of the reported uneven vascular distribution of the enzyme, angiotensin converting enzyme (ACE), we hypothesized that the magnitude of blood pressure responses to bolus injections of angiotensin I (Ang I) and bradykinin (BK) would be dependent upon the route of administration, i.e., intra-arterial (i.a.) or intra-venous (i.v.). Anesthetized rats with cannulas in the left carotid artery and the right internal jugular vein were given bolus injections of each agent, alternating between the two cannulas. Intra-venous injections of Ang I produced transient increases in arterial pressure that were significantly greater (27 +/- 12%) and longer (7 +/- 7%) than those induced by equimolar i.a. injections within the same preparation. Intra-venous injections of BK produced transient decreases in arterial pressure that were significantly smaller (72 +/- 4%) and shorter (78 +/- 11%) than similar i.a. injections. Unexpectedly, i.v. injections of Ang II also evoked slightly larger transient increases in arterial pressure (11 +/- 4%) than similar i.a. injections. These results suggest that enzymatic alterations of Ang I and BK probably by angiotensin converting enzyme during their initial passage through the pulmonary circulation has a small but significant influence on their pressor effects.
authors.affiliation: Department of Medical and Molecular Physiology, University of Minnesota, Duluth School of Medicine, 55812, USA. lheller@d.umn.edu
authors.forename: L J
authors.initials: LJ
authors.lastname: Heller
authors.forename: D E
authors.initials: DE
authors.lastname: Mohrman
mesh_terms: D000803:Angiotensin I / Q000008:administration & dosage / Q000494:pharmacology*; D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001920:Bradykinin / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007269:Injections, Intra-Arterial; D007275:Injections, Intravenous; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000804:Angiotensin II; D000803:Angiotensin I; D001920:Bradykinin