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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.

Calmodulin (CaM) is a sensor protein, which takes part in calcium-dependent signaling, regulating processes like growth, differentiation, proliferation and motility. Calmodulin binds calcium ions during induction of intracellular signaling. It is also involved in silencing of calcium signal through activation of plasma membrane Ca(2+)-ATPase (directly) or SERCA pump (indirectly). Calmodulin may affect various channels, e.g. voltage gated calcium channels (VGCCs), transient receptor potential channels (TRPCs), NMDA receptors, calcium channels dependent on cyclic nucleotides or these located in endoplasmic reticulum (ryanodine receptors and all isoforms of IP3-dependent receptors).

Gamma-aminobutyric acid is a major inhibitory neurotransmitter in the central nervous system. GABA metabolism is dependent on the activity of three enzymes: glutamic acid decarboxylase, GABA-transaminase and succinic semialdehyde dehydrogenase. Decreased activity of these enzymes may cause many neurological syndromes, such as stiff-person syndrome, chronic fatigue syndrome, anxiety disorders and seizures. This article is a review of most important problems related to an impairment of GABA metabolism.