RESUMO
El sistema renina-angiotensina-aldosterona (SRAA) y sus efectos en el flujo sanguíneo e hidrosalino han sido estudiados a nivel cardiovascular y renal. La activación del SRAA en otros órganos tiene efectos tanto locales como sistémicos, alterando la macro y microvascultura de los órganos periféricos. En el cerebro, el SRAA regula la presión arterial (PA) a través del sistema nervioso simpático. El eje enzima convertidora de angiotensina/angiotensina II/receptor de angiotensina 1 (ECA/Ang II/AT1), vía clásica, y enzima convertidora de angiotensina tipo 2/angiotensina (1-7)/receptor Mas (ECA2/Ang [1-7]/MasR), vía no clásica, modulan la respuesta simpática. Su descompensación y acumulación de Ang II propician la hipertensión neurogénica (HTN) y otras patologías vasculares. El eje aminopeptidasa/angiotensina IV/receptor de angiotensina 4 (AMN/Ang IV/AT4), exclusivo del cerebro, condiciona la microvasculatura cerebral e interviene en la cognición, la memoria y el aprendizaje. Esta revisión propone descifrar los mecanismos de regulación de la PA por el SRAA central, así como revisar sus funciones y su contribución en la neuroprotección y la cognición. (AU)
The renin-angiotensin-aldosterone (RAAS) system and its effects on blood pressure and the regulation of water and electrolyte balance have been studied focusing on the cardiovascular and renal system. The activation of RAAS in other organs has local and systemic repercussions by modeling the macro- and microvasculture of peripheral organs. The brain RAAS influence on systemic blood pressure through the sympathetic nervous system. The angiotensin converting enzyme/angiotensin II/angiotensin 1 receptor axis (ACE/AngII/AT1), classical pathway, and angiotensin converting enzyme type 2/angiotensin (1-7)/Mas receptor (ACE2/Ang (1-7)/MasR), non-classical pathway, are involved in the modulation of the sympathetic response. The imbalance of these two axes with subsequently Ang II accumulation promote neurogenic hypertension and other vascular pathologies. The aminopeptidase/angiotensin IV/angiotensin 4 receptor (AMN/Ang IV/AT4) axis, which is exclusive of the brain, acts on cerebral microvasculature and participates in cognition, memory, and learning. The aim of this review is to decipher the major central RAAS mechanisms involved in blood pressure regulation. In addition, paracrine functions of brain RAAS and its role in neuroprotection and cognition are also described in this review. (AU)
Assuntos
Humanos , Hipertensão , Sistema Renina-Angiotensina , Cérebro/fisiologia , Cérebro/metabolismo , Pressão ArterialRESUMO
The renin-angiotensin-aldosterone (RAAS) system and its effects on blood pressure and the regulation of water and electrolyte balance have been studied focusing on the cardiovascular and renal system. The activation of RAAS in other organs has local and systemic repercussions by modeling the macro- and microvasculture of peripheral organs. The brain RAAS influence on systemic blood pressure through the sympathetic nervous system. The angiotensin converting enzyme/angiotensin II/angiotensin 1 receptor axis (ACE/AngII/AT1), classical pathway, and angiotensin converting enzyme type 2/angiotensin (1-7)/Mas receptor (ACE2/Ang (1-7)/MasR), non-classical pathway, are involved in the modulation of the sympathetic response. The imbalance of these two axes with subsequently Ang II accumulation promote neurogenic hypertension and other vascular pathologies. The aminopeptidase/angiotensin IV/angiotensin 4 receptor (AMN/Ang IV/AT4) axis, which is exclusive of the brain, acts on cerebral microvasculature and participates in cognition, memory, and learning. The aim of this review is to decipher the major central RAAS mechanisms involved in blood pressure regulation. In addition, paracrine functions of brain RAAS and its role in neuroprotection and cognition are also described in this review.
