Comparison of blood pressure responses to intra-arterial and intra-venous injections of angiotensin I, angiotensin II and bradykinin

• Published in: Life sciences (1973) 1998-01, Vol.62 (9), p.PL121-PL125
• Main Authors: Heller, L J, Mohrman, D E
• Format: Article
• Language: English
• Subjects: Angiotensin I - administration & dosage; Angiotensin I - pharmacology; Angiotensin II - administration & dosage; Angiotensin II - pharmacology; Animals; Blood Pressure - drug effects; Bradykinin - administration & dosage; Bradykinin - pharmacology; Female; Injections, Intra-Arterial; Injections, Intravenous; Rats; Rats, Sprague-Dawley
• ISSN: 0024-3205
• DOI: 10.1016/S0024-3205(97)01189-2

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.