Cardiovascular effects of angiotensin A: A novel peptide of the renin–angiotensin system. (December 2014)

• Record Type: Journal Article
• Authors: Coutinho, Danielle CO; Foureaux, Giselle; Rodrigues, Keyla DL; Salles, Rodrigo LA; Moraes, Patrícia L; Murça, Tatiane M; De Maria, Marilda LA; Gomes, Enéas RM; Santos, Robson AS; Guatimosim, Sílvia; Ferreira, Anderson J
• Is Part Of: Journal of the renin-angiotensin-aldosterone system. Volume 15:Number 4(2014:Dec.)
• Page Start: 480
• Page End: 486
• Publication Date: 2014-12
• Subjects: Angiotensin II -- angiotensin-converting enzyme inhibitors -- AT1 receptor blockers -- cardiac function -- blood pressure -- calcium handling; Renin-angiotensin system -- Periodicals; 616.132
• DOI: 10.1177/1470320312474856
• Languages: English
• ISSNs: 1470-3203

Abstract

Introduction: Angiotensin (Ang) A was first identified in human plasma and it differs from Ang II in Ala 1 instead of Asp 1 . Here, we hypothesized that the actions of this peptide might explain, at least partially, the limited effects of AT1 R antagonists in certain cardiovascular diseases. Materials and methods: The effects of Ang A and Ang II on blood pressure (BP) and heart function were compared. Importantly, participation of AT1 R in these effects was evaluated. Furthermore, the effects of these two peptides on ischemia/reperfusion arrhythmias and involvement of calcium in these effects were investigated. Results: Administration of increasing doses of these peptides caused elevations in BP at comparable magnitude. AT1 R blockade completely abolished these effects. The actions of these peptides in cardiac function were quite similar although the effects of Ang A were only partially blocked by losartan. Interestingly, Ang II elicited an increase in the duration of ischemia/reperfusion arrhythmias while Ang A had no effect on cardiac rhythm during reperfusion. In accordance, differently to Ang II, Ang A did not induce any significant effect on calcium transient during baseline and ischemic stress conditions. Conclusions: These data suggest that the existence of alternative peptides of the renin–angiotensin system (RAS) might contribute to the limited effects of angiotensin receptor blockers (ARBs) in certain pathophysiological circumstances.