title: Differential control of vasomotion by angiotensins in the rostral ventrolateral medulla of hypertensive rats.
abstract: 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 1.2g/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.
authors.affiliation: Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil. Electronic address: patferri@hotmail.com.
authors.forename: Patrícia M
authors.initials: PM
authors.lastname: Ferreira
authors.affiliation: Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil.
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Xavier
authors.affiliation: Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, MG, Brazil.
authors.forename: Andreia C
authors.initials: AC
authors.lastname: Alzamora
authors.affiliation: Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica (INCT-Nanobiofar), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil.
authors.forename: Robson A S
authors.initials: RA
authors.lastname: Santos
authors.affiliation: Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica (INCT-Nanobiofar), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Campagnole-Santos
mesh_terms: D000803:Angiotensin I / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008526:Medulla Oblongata / Q000098:blood supply* / Q000187:drug effects*; D008638:Mesenteric Arteries / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects; D013152:Splanchnic Circulation / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D010446:Peptide Fragments; D000804:Angiotensin II; D000803:Angiotensin I; C118790:angiotensin I (1-7)
keywords: Ang II; Ang-(1–7); Arterial pressure; Rostral ventrolateral medulla; Spontaneously hypertensive rats; Vascular blood flow