GABA immunoreactive axons and growth cones in the developing chicken optic nerve and tract

Granda, R.H.; Crossland, W.J.

doi:10.1016/0165-3806(91)90225-8

Cited by 5 publications

(2 citation statements)

References 34 publications

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“…Such neurons have not been detected in the embryonic or posthatch chicken ION (Granda and Crossland, 1991;C.S. von Bartheld, unpublished) and thus may be a species difference.…”

mentioning

confidence: 89%

Target‐derived BDNF (brain‐derived neurotrophic factor) is essential for the survival of developing neurons in the isthmo‐optic nucleus

Bartheld

Johnson

2001

J of Comparative Neurology

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Neurons in the peripheral nervous system depend on single neurotrophic factors, whereas those in the brain are thought to utilize many different trophic factors. This study examined whether some neurons in the brain critically depend on a single trophic factor during development. Neurons in the isthmo-optic nucleus (ION) of chick embryos respond to exogenous brain-derived neurotrophic factor (BDNF). Relatively high concentrations of endogenous BDNF were present in the ION of 14-18-day-old chick embryos. ION target cells in the retina were immunolabeled for BDNF but showed surprisingly low levels of BDNF mRNA. These data suggest that ION target cells derive some BDNF from other retinal sources. No BDNF mRNA was detected in the ION itself. ION neurons had a very efficient retrograde transport system for BDNF and exogenous BDNF arrived in the ION intact. When the ION was deprived of endogenous trkB ligands by injection of trkB fusion proteins in the eye, cell death of ION neurons was enhanced, and this effect was mimicked by BDNF-specific blocking antibodies in the eye. TrkB fusion proteins in the retina induced cell death of ION neurons prior to visible effects on ION target cells in the retina. Immunolabel for endogenous BDNF was sparse in pyknotic ION neurons, suggesting that ION neurons with low BDNF content were eliminated by apoptosis. These data show that BDNF is an essential target-derived trophic factor for developing ION neurons and thereby validate the neurotrophic hypothesis for at least one neuronal population in the brain.

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“…Such neurons have not been detected in the embryonic or posthatch chicken ION (Granda and Crossland, 1991;C.S. von Bartheld, unpublished) and thus may be a species difference.…”

mentioning

confidence: 89%

Target‐derived BDNF (brain‐derived neurotrophic factor) is essential for the survival of developing neurons in the isthmo‐optic nucleus

Bartheld

Johnson

2001

J of Comparative Neurology

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“…In the developing vertebrate visual system, GABA and its receptors are expressed in the retina, optic nerve, and optic tract (Mosinger et al, 1986;Koulen et al, 1998;Granda and Crossland, 1991;Redburn, 1992;Sakatani et al, 1992;Sandell et al, 1994;Sun and Chiu, 1999;Catsicas and Mobbs, 2001). Recently, it was shown that endogenous GABA modulates the pattern of intracellular calcium (Ca 2ϩ ) waves in the embryonic retina (Catsicas and Mobbs, 2001).…”

Section: Introductionmentioning

confidence: 99%

GABA and development of the Xenopus optic projection

Ferguson

McFarlane

2002

J. Neurobiol.

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In the developing visual system of Xenopus laevis retinal ganglion cell (RGC) axons extend through the brain towards their major target in the midbrain, the optic tectum. Enroute, the axons are guided along their pathway by cues in the environment. In vitro, neurotransmitters have been shown to act chemotropically to influence the trajectory of extending axons and regulate the outgrowth of developing neurites, suggesting that they may act to guide or modulate the growth of axons in vivo. Previous work by Roberts and colleagues (1987) showed that populations of cells within the developing Xenopus diencephalon and mid-brain express the neurotransmitter gamma amino butyric acid (GABA). Here we show that Xenopus RGC axons in the midoptic tract grow alongside the GABAergic cells and cross their GABA immunopositive nerve processes. Moreover, RGC axons and growth cones express GABA-A and GABA-B receptors, and GABA and the GABA-B receptor agonist baclofen both stimulate RGC neurite outgrowth in culture. Finally, the GABA-B receptor antagonist CGP54626 applied to the developing optic projection in vivo causes a dose-dependent shortening of the optic projection. These data indicate that GABA may act in vivo to stimulate the outgrowth of Xenopus RGC axons along the optic tract.

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Expression of neuronal markers, synaptic proteins, and glutamine synthetase in the control and regenerating lizard visual system

Romero-Aleman

Monzon-Mayor

Santos

et al. 2010

J of Comparative Neurology

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Spontaneous regrowth of retinal ganglion cell (RGC) axons occurs after optic nerve (ON) transection in the lizard Gallotia galloti. To gain more insight into this event we performed an immunohistochemical study on selected neuron and glial markers, which proved useful for analyzing the axonal regrowth process in different regeneration models. In the control lizards, RGCs were beta-III tubulin- (Tuj1) and HuCD-positive. The vesicular glutamate transporter-1 (VGLUT1) preferentially stained RGCs and glial somata rather than synaptic layers. In contrast, SV2 and vesicular GABA/glycine transporter (VGAT) labeling was restricted to both plexiform layers. Strikingly, the strong expression of glutamine synthetase (GS) in both Müller glia processes and macroglial somata revealed a high glutamate metabolism along the visual system. Upregulation of Tuj1 and HuCD in the surviving RGCs was observed at all the timepoints studied (1, 3, 6, 9, and 12 months postlesion). The significant rise of Tuj1 in the optic nerve head and optic tract (OTr) by 1 and 6 months postlesion, respectively, suggests an increase of the beta-III tubulin transport and incorporation into newly formed axons. Persistent Tuj1(+) and SV2(+) puncta and swellings were abnormally observed in putative degenerating/dystrophic fibers. Unexpectedly, neuron-like cells of obscure significance were identified in the control and regenerating ON-OTr. We conclude that: 1) the persistent upregulation of Tuj1 and HuCD favors the long-lasting axonal regrowth process; 2) the latter succeeded despite the ectopia and dystrophy of some regrowing fibers; and 3) maintenance of the glutamate-glutamine cycle contributes to the homeostasis and plasticity of the system.

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GABA immunoreactive axons and growth cones in the developing chicken optic nerve and tract

Cited by 5 publications

References 34 publications

Target‐derived BDNF (brain‐derived neurotrophic factor) is essential for the survival of developing neurons in the isthmo‐optic nucleus

Target‐derived BDNF (brain‐derived neurotrophic factor) is essential for the survival of developing neurons in the isthmo‐optic nucleus

GABA and development of the Xenopus optic projection

Expression of neuronal markers, synaptic proteins, and glutamine synthetase in the control and regenerating lizard visual system

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