DIFFERENTIATION OF PLURIPOTENT EMBRYONIC STEM-CELLS INTO THE NEURONALLINEAGE IN-VITRO GIVES RISE TO MATURE INHIBITORY AND EXCITATORY NEURONS

Embryonic stem (ES) cells represent a suitable model to analyze cell d ifferentiation processes in vitro. Here, we report that pluripotent ES cells of the line BLC 6 differentiate in vitro into neuronal cells po ssessing the complex electrophysiological and immunocytochemical prope rties of postmitotic nerve cells. In the course of differentiation BLC 6-derived neurons differentially express voltage-dependent (K+, Na+, Ca2+) and receptor-operated (GABA(A), glycine, AMPA, NMDA receptors) i onic channels. They generate fast Na+-driven action potentials and are functionally coupled by inhibitory (GABAergic) and excitatory (glutam atergic) synapses as revealed by measurements of postsynaptic currents . Moreover, BLC 6-derived neurons express neuron-specific cytoskeletal , cell adhesion and synaptic vesicle proteins and exhibit a Ca2+-depen dent GABA secretion. Thus, the ES cell model enables the investigation of cell lineage determination and signaling mechanisms in the develop ing nervous system from a pluripotential stem cell to a differentiated postmitotic neuron. The in vitro differentiation of neurons from ES c ells may be an excellent approach to study by targeted gene disruption a variety of neuronal functions.