Immunocytochemical analysis of misplaced rhodopsin-positive cells in the developing rodent retina.
During the first postnatal weeks of the developing rodent retina, rhodopsin can be detected in a number of neuron-like cells in the inner retina. In the present study, we aim to characterize the morphology, number and staining characteristics of this peculiar population. Misplaced rhodopsin-positive cells (MRCs) were analyzed on retinas of four rodent species, labeled with various rhodopsin-specific antibodies. To investigate their possible relation with non-photoreceptor cells, sections were double-stained against distinct retinal cell types and proteins of the phototransduction cascade. The possibility of synapse formation and apoptosis were also investigated. In all species studied, misplaced cells comprised a few percent of all rhodopsin-positive elements. This ratio declined from the end of the second week and MRCs disappeared nearly completely from the retina by P24. MRCs resembled resident neurons of the inner retina, while outer segment-like processes were seen only rarely. MRCs expressed no other photopigment types and showed no colocalization with any of the bipolar, horizontal, amacrine and ganglion cell markers used. While all MRCs colabeled for arrestin and recoverin, other proteins of the phototransduction cascade were only detectable in a minority of the population. Only a few MRCs were shown to form synaptic-like endings. Our results showed that, during development, some rhodopsin-expressing cells are displaced to the inner retinal layers. Although most MRCs lack morphological features of photoreceptors, they contain some but not all, elements of the phototransduction cascade, indicating that they are most probably misplaced rods that failed to complete differentiation and integrate into the photoreceptor mosaic.
Department of Human Morphology and Developmental Biology, Semmelweis University, Tűzoltó u. 58, 1094, Budapest, Hungary, szabo.klaudia@med.semmelweis-univ.hu.
Klaudia
K
Szabó
Arnold
A
Szabó
Anna
A
Enzsöly
Agoston
A
Szél
Akos
A
Lukáts
D025042:Amacrine Cells / Q000166:cytology / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D006224:Cricetinae; D063928:Ependymoglial Cells / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D055537:Light Signal Transduction; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000378:metabolism; D055351:Retinal Neurons / Q000166:cytology / Q000378:metabolism; D012243:Rhodopsin / Q000378:metabolism*; D017299:Rod Opsins / Q000378:metabolism; D013569:Synapses / Q000378:metabolism; D000099210:Melanopsin
D012243:Rhodopsin; D017299:Rod Opsins; D000099210:Melanopsin