title: Differentiation of photoreceptors, glia, and neurons in the retina of the cichlid fish Aequidens pulcher; an immunocytochemical study.
abstract: Light-microscopic immunocytochemistry was carried out to investigate the developmental dynamics of several neurochemical markers in the retina of blue acara (Aequidens pulcher). As a rule, double-label experiments were performed in order to determine the absolute and relative timing of the appearance of these markers. The diameter of eye-ball (from 0.6 to 1.2 mm) and the body length (from 4.6 to 9.4 mm) enlarged in parallel during the observation period of 2 to 9 days after spawning (day 2-9); hatching took place usually on day 2. Immunoreactive proliferating cell nuclear antigen (ir-PCNA) was present in all neuroblasts (the embryonic homogeneous cell stage; day 1.0-2.0), but was lost progressively in a center-to-periphery and apparent proximal-to-distal sequence as the cells and layers differentiated. In late larvae and juveniles, ir-PCNA was confined to a ring of dividing neuroblasts at the retinal margin and to a population of scattered rod precursors in the outer nuclear layer. Immunoreactive structures of representative antigens progressively appeared after ir-PCNA had decayed. Around hatching, at the synaptic separation stage (day 2.0-2.5), luteinizing hormone-releasing hormone-ir centrifugal fibers, visinin-ir cones, glial fibrillary acidic protein-ir structures and gamma-aminobutyric acid-ir cell bodies appeared, which were followed by the emergence of rhodopsin-ir rods and tyrosine hydroxylase-ir interplexiform cells (on day 2.5-3.0) and serotonin-, neuropeptide Y- and substance P-ir amacrine cells (on day 3.0-4.0). The results indicate that photoreceptor cells, and especially rods start to differentiate at an earlier stage of retinogenesis than has previously been proposed. In addition, an extraretinal tissue in the brain identified as the prospective pineal organ was found to be visinin- and rhodopsin-immunoreactive on day 1.5-2.0 before these photoreceptor-specific antigens became positive in the retina.
authors.affiliation: Anatomisches Institut, Universität Tübingen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Negishi
authors.forename: H J
authors.initials: HJ
authors.lastname: Wagner
mesh_terms: D000818:Animals; D001827:Body Height / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D005123:Eye / Q000033:anatomy & histology / Q000737:chemistry* / Q000254:growth & development; D007150:Immunohistochemistry; D009412:Nerve Fibers / Q000737:chemistry; D009419:Nerve Tissue Proteins / Q000032:analysis; D009457:Neuroglia / Q000737:chemistry* / Q000166:cytology; D009474:Neurons / Q000737:chemistry; D009479:Neuropeptides / Q000032:analysis; D010471:Perches / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*; D010786:Photoreceptor Cells / Q000737:chemistry* / Q000166:cytology; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D012160:Retina / Q000033:anatomy & histology / Q000737:chemistry* / Q000254:growth & development; D005680:gamma-Aminobutyric Acid / Q000032:analysis
chemical_list: D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D018809:Proliferating Cell Nuclear Antigen; D005680:gamma-Aminobutyric Acid