Central and peripheral actions of angiotensin-(1-7).
1. In this article we review the physiological actions of the heptapeptide angiotensin-(1-7) [Ang-(1-7)] at the periphery and on central pathways involved in the control of arterial pressure. Peripherally Ang-(1-7) has been shown to present a potent antidiuretic effect on water-loaded rats. Microinjection of pmol amounts of Ang-(1-7) into the dorsomedial or ventrolateral medulla (VLM) of anesthetized rats produces cardiovascular effects comparable to Ang II. In addition, in vitro experiments have shown that Ang-(1-7) has a potent vasopressin and prostaglandin releasing activity and excites neuronal activity in the hypothalamus and medulla. 2. Evidence for the existence of a new angiotensin receptor subtype that mediates the central cardiovascular actions of this active peptide of the renin-angiotensin system (RAS) is also provided. Neither the AT1 receptor antagonist DUP 753 or the AT2 receptor antagonist CGP 42112A blocked the pressor response produced by microinjection of Ang-(1-7) into the rostral VLM. However, the effect of Ang-(1-7) on VLM was completely abolished by the non-specific angiotensin receptor antagonist, Sar1-Thr8-Ang II. 3. The data presented here reinforce the hypothesis of the existence of complex site-specific interactions between multiple angiotensins and multiple receptors in the mediation of important central and peripheral effects of the RAS.
Santos
R A
RA
Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
Campagnole-Santos
M J
MJ
D000803:Angiotensin I; D000804:Angiotensin II / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D017704:Baroreflex / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000502:physiology*; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology / Q000502:physiology*; D051381:Rats; D011945:Receptors, Angiotensin / Q000502:physiology; D012084:Renin-Angiotensin System / Q000502:physiology
D010446:Peptide Fragments; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D000803:Angiotensin I; C118790:angiotensin I (1-7)