The eye in the brain: retinoic acid effects morphogenesis of the eye and pathway selection of axons but not the differentiation of the retina in Xenopus laevis.
We have analyzed the effects of all-trans retinoic acid (RA) on the morphogenesis, differentiation and projection of the eye of Xenopus. RA was applied in concentrations of 10(-5), 5 x 10(-6) and 10(-6) M at stages 9-17. Animals were reared until stages 40-48. RA applied before stage 11 1/2, abated completely formation of an eye or a retina, at later stages it led to the formation of microphthalmic eyes. Even in the absence of an eye parts of the forebrain had characteristics of the retina, but rods and cones reached then into the lumen of the third ventricle. The projection of eyes of RA-treated animals was revealed with rhodamine dextran amine. Ganglion cell axons projected bilaterally to the tectum, to the hindbrain, the contralateral retina and, occasionally, to the olfactory bulb. RA affects both morphogenesis of the eye and pathway selectivity of ganglion cell axons but not differentiation of the neural retina.
Manns
M
M
University of Bielefeld, Faculty of Biology, F.R.G.
Fritzsch
B
B
D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure*; D002454:Cell Differentiation / Q000502:physiology; D005123:Eye / Q000166:cytology / Q000294:innervation*; D009434:Neural Pathways / Q000502:physiology; D012160:Retina / Q000166:cytology* / Q000502:physiology; D014212:Tretinoin / Q000494:pharmacology*; D014981:Xenopus
D014212:Tretinoin