Figure 4

CRABP is transiently expressed by type-II cholinergic amacrine cells during embryonic development. Vertical sections of chick retina labeled with antibodies to CRABP (green) and ChAT (red). Sections were obtained from embryos at E6 (a-c), E7 (d-f), E8 (g-i), E11 (j-l), E16 (m-o), E18 (p-r) or from a postnatal chick (P3; s-u). Arrows indicate the IPL strata that are occupied by the dendrites of type-II cholinergic amacrine cells, and arrow-heads indicate representative cells that are immunoreactive for ChAT and CRABP. The calibration bar (50 μm) in panel l applies to panels a-l, the bar in r applies to p-r, and the bar in u applies to to m-o and s-r. The insets in panels o and u are high-magnification confocal images of the inner plexiform layer where the dendrites or the type-II cells terminate. Abbreviations: CRABP – cellular retinoic acid binding protein; ChAT – choline acetyltransferase; INL – inner nuclear layer; IPL – inner plexiform layer; GCL – ganglion cell layer.