Figure 2.
Comparable maturation of the typical GABAergic population in utero (A–G) and in organotypic culture (H–L). A, B, At E11.5, sparse GABA immunoreactivity is first detected at brachial levels (A), whereas no GABA labeling is present at lumbar levels (B). C, D, At E13.5, numerous cells are detected at brachial levels, whereas few stained cells are revealed at lumbar levels. E, F, At E15.5, the reverse pattern is observed in the spinal cord with a low number of GABA-IR cells at brachial levels (E) and a high number of GABA-IR cells at lumbar levels (F). G, The quantitative analysis reveals peaks (asterisks) of GABA-IR density at E13.5 and at E15.5, at the brachial level (black bars) and at the lumbar level (gray bars), respectively (*p < 0.05; Dunn's test), compared with E11.5. H, I, In organotypic culture after 2 DIC, numerous GABA-IR cells are detected at the brachial level (H), whereas the immunoreactivity is less apparent at the lumbar level (I). J, K, After 6 DIC, fewer GABA somata are present at the brachial level, whereas a denser population of GABA-IR cells is present at the lumbar level. L, Quantification of the number of GABA-IR cells indicates a peak (asterisks) at 2 DIC at the brachial level and at 6 DIC at the lumbar level (*p < 0.05; Dunn's test; compared with E11.5). The arrows indicate the GABA-IR process, and arrowheads indicate GABA-IR soma. n = 6 for each stage of development. Scale bars, 20 μm.