Transforming growth factor-alpha (TGF-alpha ) and epidermal growth factor receptor (EGFR) immunoreactivities were examined in the cerebral cortex of the rat during postnatal development. TGF-alpha -immunoreactive cells were found at birth in all cortical layers except the molecular layer. TGF-alpha -immunoreactive cells were most abundant in the parietal cortex at P20. The intensity and number of the TGF-alpha -immunoreactive cells increased at postnatal days 15 or 20 (P15 - P20). Mature patterns of TGF-alpha -immunoreactive cells were achieved at P20. EGFR -immunoreactive cells appeared only in dorsal endopiriform cortex at P0. The first EGFR -immunoreactive cells were observed in the neocortex at P3. These cells were most abundant in the parietal cortex at P90. In adult, the most prominent EGFR immunoreactivity occured in layer IV, V and VI. These cells were numerous in the frontal and parietal cortex, diminishing laterally towards the insular cortex. Adult patterns were reached on and after P10. The time of appearance and localization of EGFR immunoreactivity correlated with functional activity in the different cortical areas. No clear labelling of glial cells with TGF-alpha and EGFR antibodies was found. TGF -alpha and EGFR immunoreactivity was observed in the majority of neurons in the postnatal developing and adult cerebral cortex of the rat. Also double -immunohistochemistry with antibodies to TGF-alpha and EGFR showed co-localization of TGF -alpha and EGFR in neurons of the cerebral cortex. Co-localization of TGF-alpha and EGFR was first detectable in most cortices at P3. By P10, these neurons showed immature neuronal features. The present results showing TGF -alpha and EGFR immunoreactivity is widely distributed in the postnatal developing (except P0) and adult cerebral cortex, mainly localized in neurons. And TGF-alpha and EGFR co-localize in most neurons, thus indicating that most EGFR -containing cells are TGF-alpha -synthesizing cells. In addition to difference of time of appearance and mature neuronal pattern suggest that TGF-alpha has the capacity of activating the EGFR in the normal postnatal developing cerebral cortex, therefore, TGF-alpha and EGFR may interact within cortical neurons through many different mechanism according to postnatal age.
Adult ; Animals ; Antibodies ; Cerebral Cortex* ; Epidermal Growth Factor* ; Humans ; Immunohistochemistry ; Neocortex ; Neuroglia ; Neurons* ; Parturition ; Rabeprazole ; Rats* ; Receptor, Epidermal Growth Factor ; Transforming Growth Factor alpha

TrkA is essential components of the high-affinity NGF receptor necessary to mediate biological effects of the neurotrophins NGF. Here we report on the expression of trkA in the cerebral cortex and diencephalon of mongolian gerbils during postnatal development. The expression of trkA was identified by immunohistochemical method. In parietal cortex and piriform cortex, higher levels of trkA-IR (immunoreactivity) were detected at 3 days postnatal (P3) and at P9. Although trkA was not expressed till P3 in the parietal cortex, it was detectable at birth in the piriform cortex. Several regions, such as Layers I, IV & VI, did not show much expression. Layer I showed especially weak labeling. In the hippocampus, thalamus, and hypothalamus, higher levels of trkA-IR were detected at P6 and P12 than earlier days. But trkA was not expressed at birth in the hippocampus, at P3 in the reticular thalamic nucleus (Rt), or neonatally in the dorsomedial hypothalamic nucleus (DM). This data shows that expression of trkA is developmentally regulated and suggests that high affinity neurotrophin-receptors mediate a transient response to neurotrophines in the cerebral cortex and diencephalon during mongolian gerbil brain ontogeny.
Animals ; Animals, Newborn ; Cerebral Cortex/*metabolism ; Diencephalon/*metabolism ; Gerbillinae/*metabolism ; Immunohistochemistry/veterinary ; Nerve Growth Factor/metabolism ; Receptor, trkA/*metabolism

It is well known that differentiation and growth of central nervous system are accomplished through relatively early stages of development. The formation of neural synapse indicates beginning of electrical signaling between neurons, so that may be a critical step in the differentiation of neurons as well as the development and growth of central nervous system. The purpose of this study was to investigate the differential expression levels and patterns of synaptic marker (synaptophysin) between superficial and deep layers of cerebral cortex according to the developmental stages. We introduced immunofluorescence staining of synaptophysin combined with densitometric analysis for the morphological quantification. The intensities of synaptophysin immuno-reactivities in deep layers of cerebral cortices were significantly higher compared to superficial layers in cerebral cortices of embryonic and neonatal mice. The significant increase of synaptophysin expression in the deep layer of cerebral cortex was mainly confined to the embryonic stage. As the expression of synaptophysin gradually decrease thereafter, the difference of expression level between superficial and deep layers could not find in the adult mice. From this study, we could confirm indirectly through synaptophysin that synaptogenic activities in the deep layer of cerebral cortex shows unique pattern especially during the early stages of brain development. Results from this study will be helpful for understanding different patterns of synaptogenesis among the various regions of developing brain.
Adult ; Animals ; Brain ; Central Nervous System ; Cerebral Cortex ; Fluorescent Antibody Technique ; Growth and Development ; Humans ; Mice ; Neurons ; Synapses ; Synaptophysin

It is well known that differentiation and growth of central nervous system are accomplished through relatively early stages of development. The formation of neural synapse indicates beginning of electrical signaling between neurons, so that may be a critical step in the differentiation of neurons as well as the development and growth of central nervous system. The purpose of this study was to investigate the differential expression levels and patterns of synaptic marker (synaptophysin) between superficial and deep layers of cerebral cortex according to the developmental stages. We introduced immunofluorescence staining of synaptophysin combined with densitometric analysis for the morphological quantification. The intensities of synaptophysin immuno-reactivities in deep layers of cerebral cortices were significantly higher compared to superficial layers in cerebral cortices of embryonic and neonatal mice. The significant increase of synaptophysin expression in the deep layer of cerebral cortex was mainly confined to the embryonic stage. As the expression of synaptophysin gradually decrease thereafter, the difference of expression level between superficial and deep layers could not find in the adult mice. From this study, we could confirm indirectly through synaptophysin that synaptogenic activities in the deep layer of cerebral cortex shows unique pattern especially during the early stages of brain development. Results from this study will be helpful for understanding different patterns of synaptogenesis among the various regions of developing brain.
Adult ; Animals ; Brain ; Central Nervous System ; Cerebral Cortex ; Fluorescent Antibody Technique ; Growth and Development ; Humans ; Mice ; Neurons ; Synapses ; Synaptophysin

Transforming growth factor-alpha (TGF-alpha) induces the proliferation and differentiation of central nervous system (CNS) as well as the survival and differentiation of postmitotic CNS neurons. Previous studies have mainly focused on the TGF-alpha expression throughout brain regions. The purpose of this study was to examine TGF-alpha immunoreactivity in the neocortex of the rat during postnatal development in detail. TGF-alpha immunoreactivity in the neocortex of the rat followed very different patterns according to postnatal ages and cortical areas. In the newborn rat, TGF-alpha-immunore-active neurons were found in all cortical areas except the gustatory area. Especially, In the parietal cortex, weakly-labelled TGF-alpha-immunoreactive neurons appeared in layers II and III from P0 to P5. Areal difference between primary and secondary somatosensory area was observed in the rostral parietal zone at P10, but TGF-alpha-immunore-active neurons distributed in layers from II to VI in the caudal parietal zone. From P15 to P90, heavily-labelled neurons appeared in layers from II to VI throughout the parietal cortex. In the granular retrosplenial area, TGF-alpha-immunore-active neurons first appeared at P15. The intensity and number of the immunoreactivity of TGF-alpha-containing neurons increased during the first 20 day of postnatal life but dramatically decreased at P30. Mature patterns of TGF-alpha-immunoreactive neurons were achieved at P20. These results indicate that TGF-alpha immunoreactivity in the neocortex may be related to the early appearance of TGF-alpha immunoreactivity in many other brain regions, and suggest that TGF-alpha is widely distributed in the brain of rat and TGF-alpha may play a role during postnatal development of the cerebral cortex.
Animals ; Brain ; Central Nervous System ; Cerebral Cortex* ; Humans ; Immunohistochemistry ; Infant, Newborn ; Neocortex ; Neurons ; Rabeprazole ; Rats* ; Transforming Growth Factor alpha

Cerebral Cortex ; growth & development ; physiology ; Evoked Potentials, Visual ; physiology ; Humans ; Infant, Newborn ; Infant, Premature ; growth & development ; Sensory Thresholds ; physiology ; Vision, Ocular ; physiology ; Visual Acuity ; physiology ; Visual Perception ; physiology

Epidermal growth factor receptor (EGFR), a 170-kDa transmembrane glycoprotein, appears to mediate epidermal growth factor (EGF) activity. Transforming growth factor-alpha and EGF produce their biological effects in numerous systems by stimulating the EGFR. In the present study, we examine the postnatal development of EGFR immunoreactivity in the different regions of the neocortex of the rat. EGFR immunoreactivity in the neocortex of the rat followed very different patterns according to postnatal ages and cortical areas. EGFR-immunoreactive cells appeared only in dorsal endopiriform cortex at P0. The first EGFR-immunoreactive cells were observed in the neocortex at P3. In the cingulate cortex, the first EGFR-immunoreactive cells appeared at P10. Also, in the retrosplenial cortex, these cells appeared in the agranular region at P3, and in the granular region at P20. These cells were most abundant in the parietal cortex at P90. In adult, the most prominent EGFR immunoreactivity occured in layer IV, V and VI. These cells were numerous in the frontal and parietal cortex, diminishing laterally towards the insular cortex. The intensity of the immunoreaction at P10 was similar to their adult pattern, but their morphologies were exhibited immature features. EGFR immunoreactivity was not found in the glial cells. The present results showing EGFR immunoreactivity is widely distributed in the postnatal developing (except P0) and adult cerebral cortex, mainly localized in neurons. These findings suggest that many growth factors may interact via the EGFR, therefore, actions to promote the proliferation and survival of neurons in the normal postnatal developing neocortex of the rat.
Adult ; Animals ; Cerebral Cortex* ; Epidermal Growth Factor* ; Glycoproteins ; Gyrus Cinguli ; Humans ; Intercellular Signaling Peptides and Proteins ; Neocortex ; Neuroglia ; Neurons ; Rabeprazole ; Rats* ; Receptor, Epidermal Growth Factor*

Tyrosine kinase A (TrkA)is an essential component of the high affinity nerve growth factor (NGF) receptor necessary to the mediate the biological effects of the neurotrophins, NGF. This study examined the distribution of TrkA-immunoreactivity (IR)cells in the postnatal rat cerebral cortex and the changes that occur in postnatal development as a result of the expression of this protein. TrkA-IR was detected at postnatal day (PD)3, PD6, PD9 and PD15. Base upon their somatodendritic morphology, the most commonly labeled cell type was the pyramidal neurons. At PD3 and PD6, layer I, II, III and V was immunopositive for TrkA, at PD9, not only at layer I, II, III, and V but also at layer VI. At PD15, the TrkA-positive cells were distributed in all layers. These TrkA-positive cells were not detected at PD0. In contrast, there was significant increase in the percentage of cells exhibiting TrkA-IR with development and the highest level was detected at PD15. These results suggest that the cerebral cortex expresses TrkA strongly during the postnatal period. Moreover, the postnatal development-related increase in the expression of TrkA-cells shows that NGF may have a trophic effect on these cerebral cortex neurons from the postnatal period.
Animals ; Animals, Newborn ; Cerebral Cortex/*growth&development/*metabolism ; Gene Expression Regulation, Developmental/*physiology ; Neurons/*metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, trkA/*metabolism

AIMTo investigate the protective effects of adenovirus-mediated hepatocyte growth factor (Ad-HGF) on injury of rat cortex neurons induced by in vitro serum-free culture.

METHODSFlow cytometry was used to assay the transfection rate of rat cortex neurons infected by adenovirus-mediated green fluorescent protein(Ad-GFP) at different multiplicity of infection (MOI) to find out the best MOI in experiment. ELISA was used to elucidate the expression patterns of cortex neuron. Neutral red stain and PI-Hoechst 33342 double stain were used to compare the viability of cortex neurons, which were cultured in serum-free medium for 6 h, 12 h, 24 h and 48 h respectively, among the Ad-HGF transfected group, the Ad-GFP transfected group and the control group.

RESULTSIt was found that when MOI was 50 PFU per cell, a transfection rate as high as 99.3% was maintained and Ad-HGF was able to express in cortex neurons effectively and persistently. In addition, the death rate and apoptotic rate of cortex neurons (infected 2 hours after seeding) cultured in serum-free medium for 12 h in Ad-HGF transfected group was significantly lower than that in both the Ad-GFP group and the control group (P < 0.05).

CONCLUSIONAd-HGF plays a protective role against in vitro serum-free culture induced injury on rat cortex neurons infected 2 hours after seeding. Though its effects on rat cortex neurons infected 5 days after seeding are not so remarkable, Ad-HGF also has the potential to protect cortex neurons from serum-free culture induced injury.

Adenoviridae ; genetics ; Animals ; Animals, Newborn ; Cells, Cultured ; Cerebral Cortex ; drug effects ; Culture Media, Serum-Free ; Hepatocyte Growth Factor ; genetics ; pharmacology ; Neurons ; drug effects ; Rats ; Rats, Wistar ; Transfection

OBJECTIVE: To study the alteration of basic fibroblast growth factor (bFGB) expression in astrocytes in vitro after mechanical injury and to understand the repair mechanism of brain injury. METHODS: Astrocytes were isolated from cerebral cortex of SD rats born in 24 hours, and then cultured and purified. The cultured astrocytes were randomly divided into control group and injury groups that were subjected to mechanical injury at 30 min, 1h, 3h, 6h, 12h, 24h, 3d, and 7d. The levels of bFGF expression in the astrocytes after injury were detected by ABC immunohistochemistry. RESULTS: More than 95% of the cultured cells were astrocytes. The levels of bFGF expression werevery low in the control group. On the other hand, increased levels of bFGF expression could be observed at 1-3h after injury. The expression levels increased significantly at 6-12h, reached peak level at 24h, remained at the high level up to 3 days, and the decreased gradually. CONCLUSION The changes of bFGF expression levels in cultured astrocytes in vitro after mechanical injury are similar to that observed in vivo experimental model, both of which show time-dependant characteristic, with only slightly earlier expression of bFGF observed in vitro. Thus, the expression of bFGF after injury can be one of evidences for estimation of brain injury intervals. the cell injury model in vitro may have superiority in the study of the molecule mechanism of tissue and cell injury.
Animals ; Astrocytes/metabolism* ; Cells, Cultured ; Cerebral Cortex/cytology* ; Fibroblast Growth Factor 2/metabolism* ; Forensic Pathology ; Immunohistochemistry ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Staining and Labeling ; Time Factors ; Wounds and Injuries