Development of starburst cholinergic amacrine cells in the retina of Tupaia belangeri.
"Starburst" cholinergic amacrines specify the response of direction-selective ganglion cells to image motion. Here, development of cholinergic amacrines was studied in the tree shrew Tupaia belangeri (Scandentia) by immunohistochemistry with antibodies against choline acetyltransferase (ChAT) and neurofilament proteins. Starburst amacrines expressed ChAT much earlier than previously thought. From embryonic day 34 (E34) onward, orthotopic and displaced subpopulations segregated from a single cluster of immunoreactive precursor cells. Orthotopic starburst amacrines rapidly took up positions in the inner nuclear layer. Displaced starburst amacrines were first arranged in a monocellular row in the inner plexiform layer, and, with a delay of 1 week, they descended to the ganglion cell layer. Conversely, dendritic stratification of displaced amacrines slightly preceded that of orthotopic ones. Starburst amacrines expressed the medium-molecular-weight neurofilament protein (NF-M) from E34 to postnatal day 11 (P11) and coexpressed alpha-internexin from E36.5 to P11. Consequently, neurofilaments composed of alpha-internexin and NF-M may stabilize developing dendrites of starburst amacrines. During the first 2 postnatal weeks, subpopulations of anti-NF-M-labeled ganglion cells costratified with the preexisting dendritic strata of starburst amacrines in the ON sublamina, OFF sublamina, or both. Hence, anti-NF-M-labeled ganglion cells may include direction-selective ones. Thereafter, NF-M and alpha-internexin proteins disappeared from starburst amacrines, and NF-M immunoreactivity was lost in the dendrites of ganglion cells. Our findings suggest that NF-M and alpha-internexin are important for starburst amacrines and ganglion cells to recognize each other and, thus, contribute to the formation of early developing retinal circuits in the inner plexiform layer.
Knabe
Wolfgang
W
Department of Anatomy and Embryology, Georg August University, D-37075 Göttingen, Germany. wknabe@gwdg.de
Washausen
Stefan
S
Happel
Nicole
N
Kuhn
Hans-Jürg
HJ
D000109:Acetylcholine / Q000378:metabolism*; D025042:Amacrine Cells / Q000166:cytology / Q000196:embryology* / Q000254:growth & development*; D000818:Animals; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000378:metabolism; D009039:Motion Perception / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D016900:Neurofilament Proteins / Q000378:metabolism; D019581:Neuropil / Q000166:cytology / Q000378:metabolism; D013045:Species Specificity; D014417:Tupaia / Q000196:embryology* / Q000254:growth & development*
D007381:Intermediate Filament Proteins; D016900:Neurofilament Proteins; C046643:alpha-internexin; C061195:neurofilament protein M; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine