Fig. 7. Relationships during in vitromaturation of gephyrin, GlyR, and GABAAR with synaptic terminals on motoneurons cultured alone. Motoneurons double-stained for synapsin and gephyrin (A1–2, B1–2, C1–2), synapsin and GlyRα/β (D1–2, E1–2, F1–2), and synapsin and GABAARβ2/3 (G1–2, H1–2, I1–2) at 3, 7, and 11 DIV (left, middle, andright columns, respectively). A–C, At 3 DIV, Geph-IR clusters accumulate in front of most but not all synaptic boutons. Numerous Geph-IR clusters are also detected at nonsynaptic loci. At 7 and 11 DIV, the number of postsynaptic Geph-IR clusters increased, and the number of nonsynaptic Geph-IR clusters decreased.D–F, At all stages, most GlyRα/β clusters are detected at nonsynaptic sites. G–I, At 3 and 7 DIV, few GABAARβ2/3 clusters are in front of synapsin-IR terminals. Their number increases at 11 DIV. Arrows, Apposed synapsin and postsynaptic markers (Geph, GlyRα/β, or GABAARβ2/3); crossed arrows, presence of synapsin-IR but not of the above-mentioned postsynaptic markers;arrowheads, presence of Geph-, GlyRα/β-, or GABAARβ2/3-IR clusters without adjacent synapsin-IR.GABAARβ2/3, GABAARβ2/3 subunits-IR; Geph, gephyrin-IR;GlyRα/β, GlyRα/β subunits-IR;Syn, synapsin-IR. A1–A2, B1–B2, C1–C2, D1–D2, E1–E2, F1–F2, G1–G2, H1–H2, I1–I, Pairs of digitized images acquired with CCD camera (A1, B1, C1, D1, E1, F1, G1, H1, I1, FITC channel; A2, B2, C2, D2, E2, F2, G2, H2, I2, TRITC channel). Scale bar, 10 μm.