GABA effects during neuronal differentiation of stem cells.

Gamma-amino butyrate (GABA) is the most prevalent inhibitory neurotransmitter in the adult brain. In this review, we summarize the pharmacology and regulation of GABAergic transmission components (biosynthetic enzymes, receptors and transporters) in adult non-neurogenic brain regions. The effects of targeted mutations in genes relevant for GABAergic functions and how they influence specific neuronal circuits and pathological states are presented. We then review GABA actions on neuronal differentiation. During brain development, GABA has depolarizing activity in cerebrocortical neural precursors, controlling cell division and contributing to neuronal migration and maturation. In the adult forebrain there are two neurogenic regions exposed to synaptic and non-synaptic GABA release. Neural stem cells and neuronal progenitors express GABA receptors in subventricular and subgranular zones. GABA effects in these cells are very similar to those found in embryonic cortical precursor cells, and therefore it is possible that this amino acid has important roles during adult brain plasticity.