The role of the brain renin-angiotensin system in neurodegenerative disorders.

The primary function of the renin-angiotensin system (RAS) is to maintain fluid homeostasis and regulate blood pressure. Several components of the RAS, namely angiotensinogen, angiotensin converting enzyme, angiotensin II and their receptors, are found in the CNS suggesting the possibility of a localized RAS in the brain. Cognitively disabling neurodegenerative disorders such as Alzheimer's disease or vascular dementia show vascular lesions, and the brain RAS has been suggested to contribute to the disease process. The aim of this brief review is to summarize the current state of research in this field with emphasis on RAS-related alterations during the course of neurodegenerative disorders.