OBJECTIVETo investigate the growth and development of nerve growth factor (NGF)-positive neurons in the cerebellum of midanaphase human fetus.

METHODSThe expression of the NGF-positive neurons in the cerebrum of human fetus was observed by immunohistochemical methods, and the integral absorbance (IA) was detected.

RESULTSBy the 3rd to 4th month of gestation, neurons was seen in the ependymal, central, and marginal plate of cerebellum; the nucleus was oval and the neurons had short and small processes. By the 5th to 7th month of gestation, the number of NGF-positive neurons increased, the expressions enhanced, the nucleus was round-, oval-, or fusiform-shaped, the neurons grew larger in size, and the Purkinje cells showed NGF-positive expression. By the 8th to 10th month of gestation, the NGF-positive expression was enhanced with deeper dying, the body of Purkinje cells grew larger gradually, and the number of NGF-positive neurons in the granular cell layer and molecular layer increased. IA of the cerebellar cortical neurons of the 3rd, 4th, 5th, 6th, 7th, and 8th month of gestation showed an increasing trend, and significant difference was observed (P < 0. 05).

CONCLUSIONNGF-positive neurons in the cerebellum play an important role for differentiation, proliferation, migration, and growth of neurons in the cerebellum.

Cerebellum ; cytology ; metabolism ; Fetus ; cytology ; metabolism ; Humans ; Nerve Growth Factor ; metabolism ; Neurons ; cytology ; metabolism ; Purkinje Cells ; metabolism

OBJECTIVETo observe the morphological changes during development of the ventricular zone (VZ) and subventricular zone (SVZ) of human fetus and the distribution pattern of neural stem cells in the VA and SVZ.

METHODSHuman fetuses at the gestational ages of 9-11 weeks, 14-16 weeks, 22-24 weeks and 32-36 weeks were collected, and the brain sections of the VZ/SVZ under the frontal lobe were examined for cytoarchitecture and distribution of nestin-positive cells with HE staining, immunohistochemistry or immunofluorescence.

RESULTSThe thickness of VZ underwent no significant changes at the gestational ages of 9-24 weeks (P>0.05) and became obviously thinner at 32 weeks (P<0.05), while the thickness of SVZ increased during 9-24 weeks (P<0.05) without obvious thinning at 32 weeks (P>0.05). VZ was thicker than SVZ at 9-11 weeks but became markedly thinner than SVZ after 14 weeks (P<0.05). The VZ contained denser cells than SVZ and showed a distinct boundary between the VZ and SVZ. Large numbers of nestin-positive cells were detected in the VZ and SVZ, and nestin immunoreactivity was found primarily in the cell processes and occasionally in the soma. Some nestin-positive cells in the SVZ had 1-3 processes. Nestin immunoreactivity in the VZ and SVZ gradually grew weak with development. The cells positive for both nestin and Ki67 were located mainly in the inner zone of the VZ and throughout the SVZ, where some nestin-positive but Ki67-negative cells were also found.

CONCLUSIONThe SVZ fully extends and the neural stem cells in the VZ/SVZ can be morphologically heterogeneous during the development of fetal human brain.

Fetus ; Frontal Lobe ; cytology ; embryology ; metabolism ; Humans ; Nestin ; metabolism ; Neural Stem Cells ; metabolism ; Neurons ; metabolism

The mushroom body (MB), a bilateral brain structure possessing about 2000-2500 neurons per hemisphere, plays a central role in olfactory learning and memory in Drosophila melanogaster. Extensive studies have demonstrated that three major types of MB neurons (α/β, α'/β' and Γ) exhibit distinct functions in memory processing, including the critical role of approximately 1000 MB α/β neurons in retrieving long-term memory. Inspired by recent findings that MB α/β neurons can be further divided into three subdivisions (surface, posterior and core) and wherein the α/β core neurons play an permissive role in long-term memory consolidation, we examined the functional differences of all the three morphological subdivisions of MB α/β by temporally precise manipulation of their synaptic outputs during long-term memory retrieval. We found the normal neurotransmission from a combination of MB α/β surface and posterior neurons is necessary for retrieving both aversive and appetitive long-term memory, whereas output from MB α/β posterior or core subdivision alone is dispensable. These results imply a specific requirement of about 500 MB α/β neurons in supporting long-term memory retrieval and a further functional partitioning for memory processing within the MB α/β region.
Adenylyl Cyclases ; metabolism ; Animals ; Drosophila Proteins ; metabolism ; Drosophila melanogaster ; cytology ; metabolism ; physiology ; Memory, Long-Term ; physiology ; Mushroom Bodies ; cytology ; physiology ; Neurons ; cytology ; metabolism ; Synapses ; metabolism ; Transcription Factors ; metabolism

AIMTo investigate the effects of oxygen-glucose deprivation on cultured rat hippocampal neurons.

METHODSThe hippocampal neurons cultured for 12 d were exposed to combined oxygen-glucose deprivation for 0.5 - 4 h and then cultured with original medium in normoxia for 28 h. Necrotic neurons were identified by 0.4% trypan blue staining and apoptotic neurons were detected by a TUNEL technique. Meanwhile, the area, perimeter and circle diameter of cell bodies were measured respectively by a photography analysis system.

RESULTSThe percentage of necrotic cells in cultured hippocampal neurons increased significantly during oxygen-glucose deprivation, but the percentage of apoptotic cells increased significantly after 28 h oxygen-glucose recovery. Photography analysis showed that area, perimeter and circle diameter of the necrotic cell bodies were larger than those of the apoptotic ones.

CONCLUSIONOxygen-glucose deprivation can lead to severe damage of cultured hippocampal neurons. The necrosis is major during acute oxygen-glucose deprivation, while the apoptosis is major 28 h after oxygen-glucose recovery.

Animals ; Cell Hypoxia ; Cells, Cultured ; Glucose ; deficiency ; Hippocampus ; cytology ; Neurons ; cytology ; Oxygen ; metabolism ; Rats ; Rats, Wistar

Neurons are the structural and functional unit of the nervous system. Precisely regulated dendrite morphogenesis is the basis of neural circuit assembly. Numerous studies have been conducted to explore the regulatory mechanisms of dendritic morphogenesis. According to their action regions, we divide them into two categories: the intrinsic and extrinsic regulators of neuronal dendritic morphogenesis. Intrinsic factors are cell type-specific transcription factors, actin polymerization or depolymerization regulators and regulators of the secretion or endocytic pathways. These intrinsic factors are produced by neuron itself and play an important role in regulating the development of dendrites. The extrinsic regulators are either secreted proteins or transmembrane domain containing cell adhesion molecules. They often form receptor-ligand pairs to mediate attractive or repulsive dendritic guidance. In this review, we summarize recent findings on the intrinsic and external molecular mechanisms of dendrite morphogenesis from multiple model organisms, including , and mice. These studies will provide a better understanding on how defective dendrite development and maintenance are associated with neurological diseases.
Animals ; Caenorhabditis elegans ; cytology ; Dendrites ; Mice ; Morphogenesis ; Nervous System Diseases ; physiopathology ; Neurons ; cytology ; Transcription Factors ; metabolism

OBJECTIVETo investigate the growth and development of brain derived neurophic factor(BDNF)-positive neurons in the frontal lobe of human fetus.

METHODSThe expression of the BDNF-positive neurons in the frontal lobe of human fetus in the 2(nd),3(rd),and 4(th) month of gestation were observed with the streptavidin-biotin-complex/immunoperoxidase(SABC)method.

RESULTSBy the second month of gestation,BDNF-positive neurons were seen in the subventricular layer of the frontal lobe of cerebellum.By the third month of gestation,BDNF-positive neurons in the central layer were in various shapes,with big nucleus,less cytoplasm,and small processes.By the fourth month of gestation,BDNF-positive neurons in the central layer grew larger in size,cytoplasm increased,the BDNF-positive expression was enhanced with deeper dyeing,and the nerve fibers and particles were distributed between neurons;also,the BDNF-positive neurons were seen in the marginal layer of the frontal lobe of cerebrum.

CONCLUSIONBDNF-positive neurons may participate in the early development of the frontal lobe of cerebrum of human fetus.

Brain-Derived Neurotrophic Factor ; metabolism ; Fetus ; metabolism ; Frontal Lobe ; embryology ; Humans ; Neurons ; cytology ; metabolism

AIMTo observe expressions and changes of Tau protein, pSer202 and Tau protein's contents during the differentiation process of bone-marrow mesenchymal stem cells (MSCs) into neural cells, and discuss Tau's effects on it.

METHODSEGF and bFGF were combined for the induction of 4th, 8th, and 12th-MSCs into neural cells. Expressions of Tau protein and pSer202 were tested by immunocytochemistry. ELISA assay was applied for testing Tau protein's contents during differentiation process.

RESULTSPositive rates of Tau protein in uninduced MSCs of 4th, 8th, and 12th-MSCs were under < 6%; After 14-day induction, the cellular morphologic characteristics in different passages were very similar to neurons, positive rates of Tau protein had no significant differences between passages (P > 0.05), but had differences with their uninduced groups (P < 0.05). There hadn't had expression of pSer202 in uninduced and induced groups of passages. ELISA assay indicated that there was an upward tendency in Tau protein's contents during the 14-day induction process, those in the 14th day had no significant differences between passages too (P > 0.05).

CONCLUSIONThe increase in Tau protein's expressions and its non-phosphorylated state may make for MSCs differentiating into normal neural cells and formation of neuronal processes.

Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; Cells, Cultured ; Guinea Pigs ; Mesenchymal Stromal Cells ; cytology ; Neurons ; cytology ; tau Proteins ; metabolism

In order to study whether marrow stromal cells (MSCs) can be induced into nerve-like cells in vitro, and the mechanism, the MSCs in Wistar rats were isolated and cultured, and then induced with DMSO and BHA in vitro. The expression of specific marking proteins in neurons, glia and neural stem cells were detected before preinduction, at 24 h of preinduction, at 6 h, 24 h, and 48 h of neuronal induction by using immunohistochemistry and Western blotting. The ultrastructural changes after the inducement were observed. The results showed that after the inducement, many MSCs turned into bipolar, multipolar and taper, and then intersected as network structure. At the same time, some MSCs had the typical neuron-like ultrastructure. Immunohistochemistry revealed that NeuN and Nestin expression was detectable after inducement, but there was no GFAP and CNP expression. Western blotting showed the expression of Nestin was strong at 6 h of neuronal induction, and decreased at 24 h, 48 h of the induction. NeuN was detectable at 6 h of neuronal induction, and increased at 24 h, 48 h of the induction. It was concluded MSCs were induced into neural stem cells, and then differentiated into neuron-like cells in vitro.
Bone Marrow Cells/*cytology ; *Cell Differentiation ; Cells, Cultured ; Glial Fibrillary Acidic Protein/metabolism ; Neurons/*cytology ; Rats, Wistar ; Stromal Cells/cytology

Stem cells are used for the investigation of developmental processes at both cellular and organism levels and offer tremendous potentials for clinical applications as an unlimited source for transplantation. Gangliosides, sialic acid-conjugated glycosphingolipids, play important regulatory roles in cell proliferation and differentiation. However, their expression patterns in stem cells and during neuronal differentiation are not known. Here, we investigated expression of gangliosides during the growth of mouse embryonic stem cells (mESCs), mesenchymal stem cells (MSCs) and differentiated neuronal cells by using high-performance thin-layer chromatography (HPTLC). Monosialoganglioside 1 (GM1) was expressed in mESCs and MSCs, while GM3 and GD3 were expressed in embryonic bodies. In the 9-day old differentiated neuronal cells from mESCs cells and MSCs, GM1 and GT1b were expressed. Results from immunostaining were consistent with those observed by HPTLC assay. These suggest that gangliosides are specifically expressed according to differentiation of mESCs and MSCs into neuronal cells and expressional difference of gangliosides may be a useful marker to identify differentiation of mESCs and MSCs into neuronal cells.
Neurons/*cytology/*metabolism ; Mice ; Mesenchymal Stem Cells/*cytology/*metabolism ; Gangliosides/*metabolism ; Embryonic Stem Cells/*cytology/*metabolism ; Cells, Cultured ; Cell Differentiation ; Animals

The rostral ventromedial medulla (RVM) is a prominent component of the descending modulatory system involved in the control of spinal nociceptive transmission. In the current study, we investigated melanocortin-4 receptor (MC4R) expression in the RVM, where the neurons involved in modulation of nociception reside. Using a line of mice expressing green fluorescent protein (GFP) under the control of the MC4R promoter, we found a large number of GFP-positive neurons in the RVM [nucleus raphe magnus (NRM) and nucleus gigantocellularis pars α (NGCα)]. Fluorescence immunohistochemistry revealed that approximately 10% of MC4R-GFP-positive neurons coexpressed tyrosine hydroxylase, indicating that they were catecholaminergic, whereas 50%-75% of those coexpressed tryptophan hydroxylase, indicating that they were serotonergic. Our findings support the hypothesis that MC4R signaling in RVM may modulate the activity of serotonergic sympathetic outflow sensitive to nociceptive signals, and that MC4R signaling in RVM may contribute to the descending modulation of nociceptive transmission.
Animals ; Female ; Male ; Medulla Oblongata ; cytology ; metabolism ; Mice ; Mice, Transgenic ; Neural Pathways ; cytology ; metabolism ; Neurons, Afferent ; cytology ; metabolism ; Nociception ; physiology ; Receptor, Melanocortin, Type 4 ; genetics ; metabolism ; Serotonergic Neurons ; metabolism ; Tyrosine 3-Monooxygenase ; metabolism