Induced spreading depression evokes cell division of astrocytes in the subpial zone, generating neural precursor-like cells and new immature neurons in the adult cerebral cortex.
OBJECTIVE
New immature neurons appear out of the germinative zone, in cortical Layers V to VI, after induced spreading depression in the adult rat brain. Because neural progenitors have been isolated in the cortex, we set out to determine whether a subgroup of mature cells in the adult cortex has the potential to divide and generate neural precursors.


METHODS
We examined the expression of endogenous markers of mitotic activity, proliferating cell nuclear antigen, and vimentin as a marker for neuronal progenitor cells, if any, in the adult rat cortex after spreading depression stimulation. Immunohistochemical analysis was also performed using antibodies for proliferating cell nuclear antigen, for vimentin, and for nestin. Nestin is a marker for activity dividing neural precursors.


RESULTS
At the end of spreading depression (Day 0), glial fibrillary acidic protein-positive cells in the subpial zone and cortical Layer I demonstrated increased mitotic activity, expressing vimentin and nestin. On Day 1, nestin(+) cells were found spreading in deeper cortical layers. On Day 3, vimentin(-)/nestin(+), neural precursor-like cells appeared in cortical Layers V to VI. On Day 6, new immature neurons appeared in cortical Layers V to VI. Induced spreading depression evokes cell division of astrocytes residing in the subpial zone, generating neural precursor-like cells.


CONCLUSIONS
Although neural precursor-like cells found in cortical Layers V to VI might have been transferred from the germinative zone rather than the cortical subpial zone, astrocytic cells in the subpial zone may be potent neural progenitors that can help to reconstruct impaired central nervous system tissue. Special caution is required when observing or treating spreading depression waves accompanying pathological conditions in the brain.
Lab for Cerebrovascular Disorders, Research Institute of National Cardio-Vascular Center, Suita, Osaka, Japan.
Jing-Hui
JH
Xue
Hiroji
H
Yanamoto
Yukako
Y
Nakajo
Norimitsu
N
Tohnai
Yoshikazu
Y
Nakano
Takuya
T
Hori
Koji
K
Iihara
Susumu
S
Miyamoto
D000367:Age Factors; D000818:Animals; D001253:Astrocytes / Q000166:cytology* / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D002540:Cerebral Cortex / Q000166:cytology* / Q000502:physiology; D013181:Cortical Spreading Depression / Q000502:physiology*; D008297:Male; D055495:Neurogenesis / Q000502:physiology; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D010841:Pia Mater / Q000166:cytology / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology