Subventricular zone
In embryonic life, the SVZ refers to a secondary proliferative zone containing neural progenitor cells, which divide to produce neurons in the process of neurogenesis.
[6] Adult SVZ neurogenesis takes the form of neuroblast precursors of interneurons that migrate to the olfactory bulb through the rostral migratory stream.
While some oligodendrocytes and ependymal cells have been found within the ribbon, they not only serve an unknown function, they are uncommon by comparison to the population of astrocytes that reside in the layer.
Actively Proliferating Cells or Transit Amplifying Progenitors (Type C): express Nestin, and form clusters interspaced among chains throughout region[10] The SVZ is a known site of neurogenesis and self-renewing neurons in the adult brain,[11] serving as such due to the interacting cell types, extracellular molecules, and localized epigenetic regulation promoting such cellular proliferation.
Overall, the authors determined that moderate insults to the SVZ allowed for recovery while more severe injuries caused permanent damage to the region.
[17] The effects of irradiation on the SVZ provided for a recognition of the amount or dose of radiation that can be given is determined mostly by the tolerance of the normal cells near the tumor.
[citation needed] In conclusion, this group was able to determine that cells in the SVZ are able to produce new neurons and glia throughout life, given it does not suffer damage as it is sensitive to any deleterious effects.
Therefore, the SVZ can recover itself following mild injury, and potentially provide for replacement cell therapy to other affected regions of the brain.
[18] NPY is a commonly expressed protein of the central nervous system that has previously been shown to stimulate proliferation of neuronal cells in the olfactory epithelium and hippocampus.
The peptide’s effects were observed through BrdU labeling and cell phenotyping that provided evidence for the migration of neuroblasts through the rostral migratory stream to the olfactory bulb (confirming previous experiments) and to the striatum.
[citation needed] As NPY is a 36 amino acid peptide associated with many physiological and pathological conditions, it has multiple receptors that are broadly expressed in the developing and mature rodent brain.
However, given in vivo studies performed by this group, the Y1 receptor displayed specifically mediated neuroproliferative effects through the induction of NPY with increased expression in the subventricular zone.
Along with the effects of NPY injection on striatal dopamine, GABA and glutamate parameters to regulate neurogenesis in the subventricular zone (previous study), this finding is still under consideration as it could be a secondary modulator of the aforementioned neurotransmitters.
This natural molecular regulation of adult neurogenesis would be adjunct with therapies of appropriate molecules such as the tested NPY and Y1 receptor, in addition to pharmacological derivatives, in providing for manageable forms of neurodegenerative disorders of the striatal area.
[citation needed] Recently, the human SVZ has been characterized in brain tumor patients at phenotypic and genetic level.
