TY - JOUR T1 - Synaptic Control of Glycine and GABA<sub>A</sub> Receptors and Gephyrin Expression in Cultured Motoneurons JF - The Journal of Neuroscience JO - J. Neurosci. SP - 7434 LP - 7449 DO - 10.1523/JNEUROSCI.19-17-07434.1999 VL - 19 IS - 17 AU - Sabine Lévi AU - Dominique Chesnoy-Marchais AU - Werner Sieghart AU - Antoine Triller Y1 - 1999/09/01 UR - http://www.jneurosci.org/content/19/17/7434.abstract N2 - We have evaluated the influence of the secretory phenotype of presynaptic boutons on the accumulation of postsynaptic glycine receptors (GlyRs), type A GABA receptors (GABAARs), and gephyrin clusters. The cellular distribution of these components was analyzed on motoneurons cultured either alone or with glycinergic and/or GABAergic neurons. In motoneurons cultured alone, we observed gephyrin clusters at nonsynaptic sites and in front of cholinergic boutons, whereas glycine and GABAA receptors formed nonsynaptic clusters. These receptors are functionally and pharmacologically similar to those found in cultures of all spinal neurons. Motoneurons receiving GABAergic innervation from dorsal root ganglia neurons displayed postsynaptic clusters of gephyrin and GABAARβ but not of GlyRα/β subunits. In motoneurons receiving glycinergic and GABAergic innervation from spinal interneurons, gephyrin, GlyRα/β, and GABAARβ formed mosaics at synaptic loci. These results indicate that (1) the transmitter phenotype of the presynaptic element determines the postsynaptic accumulation of specific receptors but not of gephyrin and (2) the postsynaptic accumulation of gephyrin alone cannot account for the formation of GlyR-rich microdomains. ER -