[Angiotensins as neuromodulators]

The primary function of angiotensin II, the main peptide of central renin-angiotensin system (RAS), is regulation of blood pressure. Recently, new functions of so-called local (or tissue) RAS have been discovered in brain. AT1 and AT2 angiotensin receptors, found in many parts of central nervous system (CNS), stimulate various signalling pathways. Gamma-amniobutyric acid (GABA), which acts by three types of receptors, is the crucial inhibitory neurotransmitter. GABA and angiotensins are found in brain regions like paraventricular nucleus of hypothalamus, nucleus tractus solitari and rostral ventrolateral medulla, all involved in blood pressure regulation. The influence of angiotensin II on GABA action is different in various CNS regions, but mainly it is associated with cardiovascular neurons activity. There are other neurotransmitters which may interact with angiotensins action. Adenosine has inhibitory effect and play important role in epilepsy. Its beneficial influence may be stronger in presence of angiotensin. Angiotensins also interact with dopamine (DA) activity by stimulation of DA-synthesizing nerves.