Preferential accumulation of [3H] corticosterone in chick brain during embryonic development

1981 ◽  
Vol 6 (4) ◽  
pp. 343-351 ◽  
Author(s):  
Fulvia Gremo ◽  
Antonia Vernadakis
Keyword(s):  
Embryonic Development ◽  
Chick Brain ◽  
Preferential Accumulation

Monofocal origin of telencephalic oligodendrocytes in the anterior entopeduncular area of the chick embryo

Development ◽  
2001 ◽  
Vol 128 (10) ◽  
pp. 1757-1769 ◽  
Author(s):  
C. Olivier ◽  
I. Cobos ◽  
E.M. Perez Villegas ◽  
N. Spassky ◽  
B. Zalc ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Chick Embryo ◽  
Embryonic Development ◽  
Progenitor Cells ◽  
Oligodendrocyte Progenitor Cells ◽  
Chick Brain ◽  
The Central Nervous System ◽  
The Brain

Oligodendrocytes are the myelin-forming cells in the central nervous system. In the brain, oligodendrocyte precursors arise in multiple restricted foci, distributed along the caudorostral axis of the ventricular neuroepithelium. In chick embryonic hind-, mid- and caudal forebrain, oligodendrocytes have a basoventral origin, while in the rostral fore-brain oligodendrocytes emerge from alar territories (Perez Villegas, E. M., Olivier, C., Spassky, N., Poncet, C., Cochard, P., Zalc, B., Thomas, J. L. and Martinez, S. (1999) Dev. Biol. 216, 98–113). To investigate the respective territories colonized by oligodendrocyte progenitor cells that originate from either the basoventral or alar foci, we have created a series of quail-chick chimeras. Homotopic chimeras demonstrate clearly that, during embryonic development, oligodendrocyte progenitors that emerge from the alar anterior entopeduncular area migrate tangentially to invade the entire telencephalon, whereas those from the basal rhombomeric foci show a restricted rostrocaudal distribution and colonize only their rhombomere of origin. Heterotopic chimeras indicate that differences in the migratory properties of oligodendroglial cells do not depend on their basoventral or alar ventricular origin. Irrespective of their origin (basal or alar), oligodendrocytes migrate only short distances in the hindbrain and long distances in the prosencephalon. Furthermore, we provide evidence that, in the developing chick brain, all telencephalic oligodendrocytes originate from the anterior entopeduncular area and that the prominent role of anterior entopeduncular area in telencephalic oligodendrogenesis is conserved between birds and mammals.

scholarly journals Ontogeny, regional distribution and properties of thyroid-hormone receptors in the developing chick brain

1984 ◽  
Vol 220 (2) ◽  
pp. 547-552 ◽  
Author(s):  
M A Haidar ◽  
P K Sarkar
Keyword(s):  
Thyroid Hormone ◽  
Embryonic Development ◽  
Hormone Receptors ◽  
Late Phase ◽  
Regional Distribution ◽  
Endogenous Hormone ◽  
Thyroid Hormone Receptors ◽  
Chick Brain ◽  
Receptor Complexes ◽  
The Brain

Studies on the thyroid-hormone receptors in the nuclei of developing chick brain revealed a single class of binding sites for tri-iodothyronine (T3) and thyroxine (T4) at all embryonic and adult ages. High-affinity [Ka = (1.85-3.3) X 10(9)M-1 and (0.3-0.6 × 10(9)M-1 for T3 and T4 respectively] receptors were detected in the brain as early as day 7 of embryonic development; their level increased progressively rapidly until day 13, and thereafter the value remained essentially constant during development. Occupancy of the receptor site with endogenous hormone was 75-90% at 7-11 days, 50-60% during the late phase of embryogenesis (13-17 days), and 80% after hatching. Comparison of the binding properties of the receptors with T3 and T4 indicates that, although the binding capacities per nucleus are almost identical, T4 has four to five times less binding affinity than T3. The half-lives of dissociation of solubilized T3- receptor complexes were 20-30h between 0 degrees and 7 degrees C, about 4h at 20 degrees C and less than 15 min at 37 degrees C. Studies of the regional distribution of receptors in the brain indicate that cerebrum has the highest concentration of T3 receptors (4000-7000 sites per nucleus); this concentration is 2-4-fold higher than that in the cerebellum, optic lobe or medulla oblongata. The overall results indicate that between 7 and 13 days of embryonic development the thyroid-hormone receptors in the embryonic chick brain, particularly in the cerebrum, assume a very high level and appear to be mostly saturated with endogenous hormone. This, and the temporal correspondence of the phenomenon with the period of neuronal growth and synaptogenesis, strongly indicate the influence of the hormone in the maturation of the developing brain.

Synthesis of sterols by chick brain and liver during embryonic development

1985 ◽  
Vol 7 (1) ◽  
pp. 131-135 ◽  
Author(s):  
C. Marco ◽  
H. Ramirez ◽  
D. Gonzalez-Pacanowska ◽  
E. Garcia-Peregrin
Keyword(s):  
Embryonic Development ◽  
Chick Brain

Live Confocal Analysis of Fertilization and Early Development

2001 ◽  
Vol 7 (S2) ◽  
pp. 1012-1013
Author(s):  
Uyen Tram ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Real Time ◽  
Early Development ◽  
Fluorescent Probes ◽  
Primary Defect ◽  
Fluorescent Analysis ◽  
Dynamic Event ◽  
Enormous Amount ◽  
Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

ADHD therapy with methylphenidate in mothers – a danger for embryonic development?

2014 ◽  
Vol 47 (06) ◽  
Author(s):  
N Bergemann ◽  
K Boyle ◽  
WE Paulus
Keyword(s):  
Embryonic Development
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