| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2808008 | Neuropeptides | 2015 | 8 Pages |
•Ang II and Ang-(1–7) at the RVLM control the vascular resistance in the renal and mesenteric beds during hypertension.•Ang II and Ang-(1–7) at the RVLM produced equipotent cardiovascular responses during hypertension.•Pressor responses produced by angiotensins in the RVLM depend on peripheral vascular resistance, but not cardiac output.
The central and peripheral renin–angiotensin systems are known for playing a key role in cardiovascular control. In the present study, we evaluated the hemodynamic effects produced by nanoinjections of angiotensin II (Ang II) or angiotensin-(1–7) [Ang-(1–7)] into the rostral ventrolateral medulla (RVLM) of adult male normotensive (Wistar—WT) and spontaneously hypertensive rats (SHR). Animals were anesthetized (urethane 1.2 g/kg) and instrumented for recording blood pressure (BP), heart rate (HR) and blood flow (BF) in the femoral, renal or mesenteric arteries. Afterwards, rats were positioned in a stereotaxic and prepared for nanoinjections (100 nl) of saline (NaCl 0.9%), Ang-(1–7) (40 ng) or Ang II (40 ng) into the RVLM. The vascular resistance (VR) was calculated by ΔMAP/ΔBF ratio. In WT, Ang-(1–7) or Ang II caused equipotent pressor effects that were not accompanied by changes in vascular resistance. However, MAP changes were greater in SHR. This strain also showed a concomitant increase in relative vascular resistance (ΔVR/VRbaseline) of renal (0.31 ± 0.07 and 0.3 ± 0.07 vs. 0.02 ± 0.01; Ang-(1–7), Ang II and Saline, respectively) and mesenteric beds (0.3 ± 0.06 and 0.33 ± 0.04 vs. 0.05 ± 0.02; Ang-(1–7), Ang II and saline, respectively). We conclude that Ang II and Ang-(1–7) at the RVLM control the vascular resistance of renal and mesenteric beds during hypertension.
