Migration of dopaminergic neurons in the embryonic mesencephalon of mice

The Size and Distribution of Midbrain Dopaminergic Populations are Permanently Altered by Perinatal Glucocorticoid Exposure in a Sex- Region- and Time-Specific Manner

“…However, if findings based on proliferation rate of the granule cells in the hippocampal dentate gyrus are more generally applicable (Gould and Cameron, 1996), it would be predicted that adrenal steroids might decrease neurogenesis, which would not be compatible with our reported increase in midbrain DA cell numbers. The main migratory period for TH-expressing cells into the SN and VTA is also complete around E16 (Kawano et al, 1995), so interference with the arrival of DA neurons into these regions would also have limited or no potential to explain the enduring effects of preand neonatal GC treatments, respectively. Notably, however, in the mouse, which exhibits an identical pattern of midbrain DA neuron development to the rat, the sharpest rise in mesencephalic TH-IR cell numbers occurs during late gestation (E17-21) (Lieb et al, 1996) and the proportion of total neurons that are TH positive in the SNc continues to rise postnatally to reach adult levels by P7-9 (Kholodilov et al, 2004), P14 (Jackson- Lewis et al, 2000), or P28 (Lieb et al, 1996).…”

Neurogenin2 identifies a transplantable dopamine neuron precursor in the developing ventral mesencephalon

“…As they leave the cell cycle, they migrate ventrally along radial glia toward the ventral surface and differentiate into TH-positive neurons within the mantle zone (17,29,34). Depending on detection method and age determination of the embryos, the first TH immunoreactive cells in mouse appear in the medial aspect of the VM around E11 (13,17). With our method of dating (vaginal plug = E0.5) and antibody (rabbit polyclonal, PelFreeze) the mesDA neurons expressing TH could be detected starting from E11.5 and in all embryos at subsequent stages.…”

“…The substantia nigra (SN, cell group A9), is the area primarily degenerated in PD, while the ventral tegmental area (VTA, group A10), has been implicated in affective disorders, drug-dependency and schizophrenia. During embryogenesis, the mesDA neurons are formed during a 3-4 day period in the mouse, starting around embryonic day (E) 11 and continuing until about E14-15 (4,17). Several developmental genes, such as Engrailed (En) 1 and 2, and Lmx1b, and cellular proteins such as aldehyde dehydrogenase-1 (Aldh1, also known as AHD-2), have been shown to be expressed in DA neuron precursors in the developing VM.…”

La ténascine-C : une molécule de la matrice extracellulaire impliquée dans le développement du système nerveux central

“…Dans les tissus adultes, au contraire, la TN-C est peu exprimée, à l'exception des sites de remodelage et de migration cellulaires, des cicatrices tissulaires, à proximité de vaisseaux sanguins endommagés et au sein de nombreux types de tumeurs [5]. La production de TN-C dans le SNC murin a été mise en évidence dès le 10 e jour de la vie embryonnaire (E10) [7]. neuro-épithélium germinatif primaire, la TN-C n'est pas exprimée par les cellules souches nerveuses précoces (par exemple à E8,5 chez la souris).…”

“…En revanche, de nombreux progéniteurs, issus de ce territoire initial et ne pouvant avec certitude être qualifiés de cellules souches in vivo, faute de marqueurs spécifiques, sont capables de produire l'hexabrachion, plus spécialement dans la zone sous-ventriculaire ( Figure 1B). Parallèlement, des sous-populations de neurones immatures, dont les cellules granulaires de l'hippocampe, certains neurones rétiniens ainsi que des motoneurones spinaux, synthéti-sent la TN-C [4,7]. Au fur et à mesure de la maturation du SNC, les niveaux d'expression de la TN-C se réduisent et sa production, chez l'adulte, n'est plus observée qu'au sein de régions particulières, incluant des sites de neurogenèse active tels que l'hippocampe, la zone sous-ventriculaire, la bordure de la voie de migration rostrale, ainsi que les zones dans lesquelles les axones ne sont pas myélinisés telles que la jonction entre le nerf optique et la rétine, et la couche moléculaire du cervelet ( Figure 1C).…”