Post-metamorphic retinal growth in Xenopus

Straznicky, Charles; Hiscock, Jennifer

doi:10.1007/bf00300592

Cited by 34 publications

(26 citation statements)

References 20 publications

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“…Retinal explants were taken from Xenopus tadpoles at stage 54, the stage at which maximal axonal outgrowth is occurring (Jacobson 1976;Beach and Jocobson 1979;Straznicky and Hiscock 1984). In the majority of cases the animals had received bilateral optic nerve cuts to stimulate outgrowth of fibres (Agranoff et al 1976), 10 days prior to removal of the eyes.…”

Section: Preparation Of Retinal Strip Explantsmentioning

confidence: 99%

Retinal axons in Xenopus show different behaviour patterns on various glial substrates in vitro

et al. 1991

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Several lines of evidence suggest that glial cells have major effects on neuronal pathfinding. We have examined in vitro whether the outgrowth pattern of Xenopus retinal fibres is influenced by the glial cells encountered as they grow to the optic tectum. Strips of retina were cultured on monolayers of glial cells from the diencephalon and from the rostral and caudal ends of the optic tectum. On glia from the caudal end of the tectum the growth of fibres from the nasal and temporal ends of the strips was different: temporal fibres were shorter and more fasciculated than nasal fibres. This difference was still discernible on glia isolated from the rostral end of the tectum, but to a lesser extent. On glia from the diencephalon there was no difference between nasal and temporal fibres.

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Section: Preparation Of Retinal Strip Explantsmentioning

confidence: 99%

Retinal axons in Xenopus show different behaviour patterns on various glial substrates in vitro

et al. 1991

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“…In Previous studies of J(enopus have shown that neurons of the GCL are about evenly distributed, with the exception of a slightly increased density gradient towards the ciliary margin (Straznicky and Hiscock 1984;Dunlop and Beazley 1984;Jenkins and Straznicky 1986 …”

Section: The Organization Of the Inl In Adult Bufo And Xenopusmentioning

confidence: 99%

“…In the former, cells are evenly distributed with a slightly higher density in the peripheral retina Straznicky and Hiscock 1984). Recently we have described the changing distribution of cells in the GCL of the Bufo retina from metamorphosis to adult animals (Nguyen and Straznicky 1989).…”

Section: Introductionmentioning

confidence: 99%

The changing distribution of neurons in the inner nuclear layer from metamorphosis to adult: a morphometric analysis of the anuran retina

1990

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The generation and changing distribution of neurons of the inner nuclear layer (INL) in the retina of two anuran species, Bufo marinus and Xenopus laevis, were studied from metamorphosis to adult. Morphometric studies were undertaken at six developmental stages in Bufo and four in Xenopus. The number and thickness of neurons in the INL were established in 29 predetermined retinal locations from serial sections of the eyes cut vertically or horizontally. The total number of neurons in the INL increased from metamorphosis to adult from 826,000 +/- 185 to 18,760,000 +/- 562 (mean +/- SD) in Bufo and from 308,000 +/- 25 to 877,000 +/- 31 in Xenopus. Over the same period the surface area of the INL increased about 50-fold from 2 mm2 to 96 mm2 in Bufo and 5-fold from 2.5 mm2 to 13 mm2 in Xenopus. In Bufo the difference between the highest cell number (central-temporal retina) and the lowest cell number in a sample area (dorsal and ventral peripheral retina) was 2.1:1 at metamorphosis. This ratio increased to 3.4:1 in the adult. Both the cell number and cell density per sample area in the INL was found to be higher along the nasotemporal meridian of the eye overlying the visual streak of the ganglion cell layer (GCL) of the retina. The retinal distribution of neurons in the INL did not change significantly during postmetamorphic growth in Xenopus. At metamorphosis a 1.7:1 difference was found between the highest neuron number (retinal ciliary margin) and lowest neuron number (retinal centre) decreasing to 1.5:1 in the adult. Retinae were labelled with 3H-thymidine in 15 mm Bufos and examined 2, 6, 12 and 18 weeks later. Higher rates of cell addition to the nasal and temporal poles of the INL were found compared with that at the dorsal and ventral poles. The retinal radial growth at the ciliary margin of the dorsal, ventral, nasal and temporal poles between the time of isotope injection and 18 weeks survival was found to be uneven; more radial elongation occurred at the nasal, dorsal and ventral poles and less at the temporal pole. These observations suggest that (a) the neuron distribution of the INL in adult animals approximates that of the GCL and (b) the visual streak-like area of the INL in Bufo develops by a sustained differential cell addition at the temporal and nasal poles of the retina.

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“…During early larval stages the mitotic activity is the highest along a crescent of the dorsal ciliary margin (Beach and Jacobson 1979;Grant et al 1980), followed, after midlarval stages, by an excess cell production in the ventral ciliary margin (Jenkins and Straznicky 1986). From the metamorphic climax onwards, an increase in mitotic activity, first in the the naso-ventral and then in the temporo-ventral part of the ciliary margin, has been reported (Tay et al 1982;Straznicky and Hiscock 1984;Dunlop and Beazley 1984).…”

Section: Introductionmentioning

confidence: 92%

“…First, a continuous addition of neurons at the ciliary margin throughout the whole life of the animal (Straznicky and Gaze 1971;Johns 1977;Dunlop and Beazley 1984), and second, a continuous retinal expansion of already formed elements (Johns and Easter 1977;Straznicky and Hiscock 1984). In mammals after birth the retina undergoes an areal increase which is not accompanied by the addition of neurons.…”

Section: The Mode Of Retinal Growth By Expansionmentioning

confidence: 97%

Morphology and retinal distribution of tyrosine hydroxylase-like immunoreactive amacrine cells in the retina of developingXenopus laevis

Zhu

Straznicky

1991

Anat Embryol

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The development of neurons immunoreactive to tyrosine hydroxylase (TH-IR) in the retina of Xenopus laevis was investigated from stage 53 tadpoles to adult, by using an antibody against tyrosine hydroxylase. At all developmental stages, most of the immunoreactive somata were located in the inner nuclear layer, and a few in the ganglion cell layer. Immunoreactive processes arborized in the scleral and vitreal sublaminae of the inner plexiform layer, indicating that these cells were bistratified amacrine cells. However, occasionally a few immunoreactive processes were observed projecting to the outer plexiform layer, suggesting the presence of TH-IR interplexiform cells. The number of immunoreactive amacrine cells in the inner nuclear layer per retina increased from 204 at stage 53 tadpole to 735 in adult, while the number of immunoreactive amacrine cells in the ganglion cell layer did not change significantly over the same period. Retinal area increased from 1.95 mm2 at stage 53 to 23.40 mm2 in the adult, and correspondingly cell density in the inner nuclear layer decreased from 104/mm2 to 31/mm2. At all stages there was an increasing density towards the ciliary margin, but this gradient decreased with age. The soma size of immunoreactive amacrine cells increased with age, and was consistently larger in the central than in the peripheral retina. Dendritic field size was estimated to increase 13-fold, from stage 53 to adult. This study shows that tyrosine hydroxylase-like immunoreactive amacrine cells are generated continuously throughout life, that after metamorphosis the retina grows more by stretching than by cell generation at the ciliary margin, and that the increase of dendritic field size is proportional to the increase in retinal surface area.

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Post-metamorphic retinal growth in Xenopus

Cited by 34 publications

References 20 publications

Retinal axons in Xenopus show different behaviour patterns on various glial substrates in vitro

Retinal axons in Xenopus show different behaviour patterns on various glial substrates in vitro

The changing distribution of neurons in the inner nuclear layer from metamorphosis to adult: a morphometric analysis of the anuran retina

Morphology and retinal distribution of tyrosine hydroxylase-like immunoreactive amacrine cells in the retina of developingXenopus laevis

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