Cardiovascular effects of small peptides of the renin angiotensin system.

The renin-angiotensin system (RAS) is a unique hormonal cascade which is composed by multiple enzymes and effector peptides. Recently, new peptides presenting biological activity have been discovered, increasing the complexity of the RAS Here, we evaluated the effects of small peptides of the RAS in coronary bed of rats. Firstly, we examined the direct effect of small angiotensinergic peptides [Angiotensin (Ang) -(1-5), Ang-(1-4) Ang-(1-3), and Ang-(1-2)] in coronary vessels. Noteworthy, it was observed that Ang-(1-4), Ang-(1-3), and Ang-(1-2) caused a significant reduction in pressure perfusion. Because Ang-(1-2) was the smallest peptide tested and presented the major effect, we decided to investigate its mechanisms of action. The effect of Ang-(1-2) was partially dependent on the Mas receptor, nitric oxide release and angiotensin-converting enzyme. Importantly, Ang-(1-2) reduced the blood pressure of Wistar rats and SHR Interestingly, SHR presented a more pronounced decrease in blood pressure levels than Wistar rats. Altogether, these data showed that angiotensinergic small peptides hold biological activities in coronary bed of rats.