Neurotransmitters as early signals for central nervous system development

During brain ontogenesis, the temporal and spatial generation of the differ ent types of neuronal and glial cells from precursors occurs as a sequence of successive progenitor stages whose proliferation, survival and cell-fate choice are controlled by environmental and cellular regulatory molecules. Neurotransmitters belong to the chemical microenvironment of neural cells, even at the earliest stages of brain development. It is now established tha t specific neurotransmitter receptors are present on progenitor cells of th e developing central nervous system and could play, during neural developme nt, a role that has remained unsuspected until recently. The present review focuses on the occurrence of neurotransmitters and their corresponding lig and-gated ion channel receptors in immature cells, including neural stem ce lls of specific embryonic and neonatal brain regions. We summarize in vitro and in vivo data arguing that neurotransmitters could regulate morphogenet ic events such as proliferation, growth, migration, differentiation and sur vival of neural precursor cells. The understanding of neurotransmitter func tion during, early neural maturation could lead to the development of pharm acological tools aimed at improving adult brain repair strategies.