Angiotensin Signaling in the Brain and Blood Vessels: Implications for Neurological and Cardiovascular Disorders

Abstract

Angiotensin signalling is found to be significant in the regulation of the system that maintains the cardiovascular and neurological balance. This regulatory mechanism affecting blood pressure, volume control, and vasomotor tone is probably mainly controlled through the renin-angiotensin system or RAS. Recent data demonstrate that although Ang II is an important regulator of brain and blood vessel function, it may also be involved in the development of pathological changes. Within the brain tissue, Ang II binds to certain receptors, such as AT1 and AT2; participating in the regulation of neuronal firing, stress and neuroinflammation. Abnormality of this signalling pathway has been linked to neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease and stroke through free radical-mediated damage, compromised blood-brain barrier integrity and neuronal death. In the vascular compartment, activates endothelial dysfunction, vascular remodelling hypertrophy and inflammation, and oxidative and proliferative changes in the vascular smooth muscle cells. These effects form the basis of the formation of cardiovascular diseases such as atherosclerosis, aneurysms and ischemic heart diseases. Interactions between central and peripheral angiotensin pathways worsen these conditions through nervous and vascular adaptation feedback loops. More recent therapies aimed at individual elements of RAS, including ACEIs, ARBs, and novel receptor ligands, reveal good potential for averting these detrimental consequences.