The renin-angiotensin system in the brain. Localization and functional significance.

Many neuropeptides have been localized in brain areas involved in cardiovascular regulation. In some cases, regulatory systems which have been originally described in other organs have been found in the brain. A prominent member of this group is the renin-angiotensin system. All of its known components have been localized in the central nervous system and angiotensin II has numerous actions in the central regulation of cardiovascular homeostasis. In addition there are actions which go beyond an active role in the control of blood pressure; these include behavioural actions and the regulation of thirst. The brain renin angiotensin system interacts with other neurotransmitters such as the catecholaminergic system and may act as a neuromodulator.