The pedunculopontine nucleus (PPN) is located in the dorso-lateral part of the ponto-mesencephalic tegmentum. The PPN is composed of two groups of neurons: one containing acetylcholine, and the other containing non-cholinergic neurotransmitters (GABA, glutamate). The PPN is connected reciprocally with the limbic system, the basal ganglia nuclei (globus pallidus, substantia nigra, subthalamic nucleus), and the brainstem reticular formation. The caudally directed corticolimbic-ventral striatal-ventral pallidal-PPN-pontomedullary reticular nuclei-spinal cord pathway seems to be involved in the initiation, acceleration, deceleration, and termination of locomotion. This pathway is under the control of the deep cerebellar and basal ganglia nuclei at the level of the PPN, particularly via potent inputs from the medial globus pallidus, substantia nigra pars reticulata and subthalamic nucleus. The PPN sends profuse ascending cholinergic efferent fibers to almost all the thalamic nuclei, to mediate phasic events in rapid-eye-movement sleep. Experimental evidence suggests that the PPN, along with other brain stem nuclei, is also involved in anti-nociception and startle reactions. In idiopathic Parkinson's disease (IPD) and parkinson plus syndrome, overactive pallidal and nigral inhibitory inputs to the PPN may cause sequential occurrences of PPN hypofunction, decreased excitatory PPN input to the substantia nigra, and aggravation of striatal dopamine deficiency. In addition, neuronal loss in the PPN itself may cause dopamine-r esistant parkinsonian deficits, including gait disorders, postural instability and sleep disturbances. In patients with IPD, such deficits may improve after posteroventral pallidotomy, but not after thalamotomy. One of the possible explanations for such differences is that dopamine-resistant parkinsonian deficits are mediated to the PPN by the descending pallido-PPN inhibitory fibers, which leave the pallido-thalamic pathways before they reach the thalamic targets.
Animal ; Basal Ganglia/cytology ; Human ; Mesencephalon/physiology* ; Mesencephalon/cytology ; Movement Disorders/etiology* ; Pons/physiology* ; Pons/cytology ; Thalamus/cytology

To observe the influence of tumor necrosis factor-alpha (TNF-alpha) on differentiation of rat mesencephalic neural stem cells (NSCs), the numbers of neurons, astrocytes and oligodendrocytes generated from NSCs were analyzed after differentiation for 3 days by using immunocytochemistry technique. The results show that: (1) TNF-alpha enhanced the proportions of neurons and oligodendrocytes in progeny of NSCs; and (2) TNF-alpha induced the proliferation of oligodendrocytes derived from NSCs, but the proliferation of astrocytes was not influenced by TNF-alpha. We conclude that the TNF-alpha could influence the application of NSCs.
Animals ; Animals, Newborn ; Astrocytes ; cytology ; Cell Differentiation ; physiology ; Cell Proliferation ; Mesencephalon ; cytology ; Neural Stem Cells ; cytology ; Neurons ; cytology ; Oligodendroglia ; cytology ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha ; physiology

The transplantation of dopaminergic neurons in the brain has been attempted in experimental animals and humans as the new treatment modality of Parkinson's disease. Before the trial of dopaminergic neuronal transplantation in human, the authors proceeded with the animal experiment of fetal dopaminergic cell transplantation in a rat Parkinson's disease model. The aims of this experiment were to confirm the availability of fetal mesencephalic cells as the donor, to compare the viability of cells according to different cell manipulation methods, and to follow up the functional recovery in the transplanted Parkinson's disease model. As a result, the authors concluded that the simple enzyme digestion method had a better cell survival rate than the multiple enzyme digestion method. Also, the transplanted mesencephalic cells could not only survive in the host animal but also promote functional recovery.
Animal ; Corpus Striatum/*physiology ; Dopamine/*metabolism ; *Fetal Tissue Transplantation ; Male ; Mesencephalon/cytology/*embryology/metabolism ; Neurons/metabolism/*transplantation ; Parkinson Disease/*surgery ; Rats ; Rats, Sprague-Dawley ; Support, Non-U.S. Gov't

OBJECTIVETo evaluate the therapeutic effect of transplantation of mesencephalic neural stem cells (mNSCs) genetically modified by glial cell line-derived neurotrophic factor (GDNF) gene in a rat model of Parkinson disease.

METHODSmNSCs isolated from the lateral component of the midbrain of fetal rats at gestational age of 14 or 15 days were cultured for 5 days before genetic modification with GFP or GDNF gene. Rat models of Parkinson disease established by stereotactic injection of 6-hydroxy dopamine in the ventral area of the midbrain and the medial forebrain bundle were randomized into 3 groups to receive PBS injection, GFP gene-modified mNSCs transplantation, or GDNF gene-modified mNSCs transplantation into the right stratum. The behavioral changes of the rats were evaluated by observing rotations induced by intraperitoneal injection of apomorphine after the transplantation, and the survival, migration and differentiation of the transplanted cells were identified by immunohistochemistry.

RESULTSTransplantation with GDNF gene-modified mNSCs significantly improved the behavioral abnormalities of the rat models as compared with PBS injection and GFP gene-modified mNSCs transplantation. At 56 days after the transplantation, a greater number of the transplanted cells survived in the rat brain and more differentiated dopaminergic neurons were detected in GDNF gene-modified mNSCs transplantation group than in GFP gene-modified mNSCs transplantation group.

CONCLUSIONGDNF gene-modified mNSCs transplantation can significantly improve dyskinesia in rat models of Parkinson disease, but the molecular mechanism needs further clarification.

Animals ; Disease Models, Animal ; Glial Cell Line-Derived Neurotrophic Factor ; genetics ; therapeutic use ; Mesencephalon ; cytology ; Neural Stem Cells ; transplantation ; Parkinson Disease ; therapy ; Rats ; Stem Cell Transplantation

In the experiment, we designed and synthesized two siRNAs based on the sequence of nuclear receptor-related factor 1 (Nurr1) mRNA. They were separately subcloned into the plasmid of pSilenCircle (pSC) containing U6 promoter. The pSC-Nurr1 vectors (pSC-N1 and pSC-N2) specific to Nurr1 gene and the negative control vector of short-hairpin RNA (shRNA) eukaryotic expression vector were constructed. We cultured the dopaminergic cell line MN9D and the verified vectors were transfected with LipofectamineTM 2000 in vitro. The positive cell clones transfected with pSC were obtained after being screened with 500 mug/ml G418. After that, the silencing effects of Nurr1 and TH mRNA or protein were detected by real time RT-PCR and Western blot. The neurite extension of MN9D cells was observed and photographed by inverted microscope. The results showed that Nurr1 mRNA expression in MN9D cells was specifically down-regulated by the vectors of pSC-N1 and pSC-N2, and the silencing effects were 62.3% and 45.6%, respectively. The dopaminergic phenotype of TH mRNA was also suppressed significantly and the silencing effects were 76.3% and 62.6%, respectively. Meanwhile, the expressions of Nurr1 and TH proteins were also significantly suppressed, and the silencing effects of Nurr1 and TH protein were 57.4%, 72.0% and 79.1%, 70.1% respectively. The negative control and liposome groups had no effect on the two genes. In conclusion, Nurr1 shRNA expressing vectors can inhibit the expressions of Nurr1 and TH mRNA or protein in MN9D cells, and Nurr1 might play a role in neurite extension of MN9D cells. Nurr1 shRNA expressing vector may provide a novel applicable strategy for the study on the function of the genes associated with Parkinson disease and the development of dopaminergic neuron.
Cell Line ; Dopaminergic Neurons ; cytology ; metabolism ; Down-Regulation ; Fetus ; Humans ; Mesencephalon ; cytology ; Neurites ; physiology ; Nuclear Receptor Subfamily 4, Group A, Member 2 ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; Transfection ; Tyrosine 3-Monooxygenase ; genetics ; metabolism

OBJECTIVETo explore the effect of static magnetic field (SMF) on the differentiation and proliferation of rat embryonic midbrain neurons cells.

METHODSThe micromass culture of rat embryonic midbrain neurons cell was applied to study the effect of varieties of SMF (1.0, 10.0, 50.0, 100.0, 200.0 mT) and FACS.

RESULTSSMF inhibited the differentiation of the cell without affecting cell proliferation. The concentration of 50% inhibition of cell differentiation (ICD(50)) was 25 mT. The concentration of 50% inhibition of cell differentiation (IVD(50)) was 45 mT.

CONCLUSIONSThe inhibition of SMF on embryonic midbrain neurons cells may be associated with impact of protein syntheses, and lipid peroxidation.

Animals ; Cell Differentiation ; radiation effects ; Cell Division ; radiation effects ; Cells, Cultured ; Electromagnetic Fields ; adverse effects ; Embryo, Mammalian ; Female ; Lipid Peroxidation ; radiation effects ; Mesencephalon ; cytology ; radiation effects ; Neurons ; cytology ; radiation effects ; Protein Biosynthesis ; radiation effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the way to induce mesenchymal stem cells (MSCs) to differentiate into dopaminergic neurons in vitro.

METHODSMSCs were obtained from rat bone marrow, cultured and passaged. MSCs used in this experiment had multipotency, which was indirectly proved by being induced to differentiate into chondrocytes and adipocytes. MSCs were cultured in medium containing 0.5 mmol/L IBMX for 2 days. Then the medium was replaced with induction medium, which contained GDNF, IL-1beta, mesencephalic glial-cell-conditioned medium and flash-frozen mesencephalic membrane fragments. The surface markers of the differentiated neurons, such as NSE, nestin, MAP-2a, b and TH were detected by immunocytochemistry and Western blot after MSCs were cultured in induction medium for 7 days and 15 days.

RESULTSMSCs differentiated into neural progenitors and expressed nestin after MSCs were incubated with medium containing IBMX for 2 d. After the medium was replaced with induction medium containing many inducing agents, MSCs differentiated into neuron-like cells and dopaminergic neuron-like cells and expressed NSE, MAP-2a, b and TH. The percentage of NSE-positive cells, MAP-2a, b-positive cells and TH-positive cells was 30.032 +/- 2.489%, 41.580 +/- 5.101% and 34.958 +/- 5.534%, respectively after MSCs were induced in medium containing GDNF, IL-1beta, mesencephalic glial-cell-conditioned medium and flash-frozen mesencephalic membrane fragments for 15 days.

CONCLUSIONMSCs can differentiate into dopaminergic neuron-like cells and are a new cell source for the treatment of neurodegeneration diseases and have a great potential for wide application.

Adipocytes ; cytology ; Animals ; Blotting, Western ; Bone Marrow Cells ; Carboxylesterase ; analysis ; Cell Differentiation ; Cells, Cultured ; Chondrocytes ; cytology ; Culture Media, Conditioned ; Dopamine ; analysis ; Intermediate Filament Proteins ; analysis ; Mesencephalon ; cytology ; Mesenchymal Stromal Cells ; cytology ; Nerve Tissue Proteins ; analysis ; Nestin ; Neurons ; cytology ; metabolism ; Phosphoprotein Phosphatases ; analysis ; Rats ; Rats, Wistar

Neuroprotective effect of scorpion venom on Parkinson's disease (PD) has already been reported. The present study was aimed to investigate whether scorpion venom heat resistant peptide (SVHRP) could attenuate ultrastructural abnormalities in mitochondria and oxidative stress in midbrain neurons of early-stage PD model. The early-stage PD model was established by injecting 6-hydroxydopamine (6-OHDA) (20 μg/3 μL normal saline with 0.1% ascorbic acid) into the striatum of Sprague Dawley (SD) rats unilaterally. The rats were intraperitoneally administered with SVHRP (0.05 mg/kg per day) or vehicle (saline) for 1 week. Two weeks after 6-OHDA treatment, the rats received behavior tests for validation of model. Three weeks after 6-OHDA injection, the immunoreactivity of dopaminergic neurons were detected by immunohistochemistry staining, and the ultrastructure of neuronal mitochondria in midbrain was observed by electron microscope. In the meantime, the activities of monoamine oxidase-B (MAO-B), superoxide dismutase (SOD) and content of malondialdehyde (MDA) in the mitochondria of the midbrain neurons, as well as the inhibitory ability of hydroxyl free radical and the antioxidant ability in the serum, were measured by corresponding kits. The results showed that 6-OHDA reduced the optical density of dopaminergic neurons, induced damage of mitochondrial ultrastructure of midbrain neurons, decreased SOD activity, increased MAO-B activity and MDA content, and reduced the antioxidant ability of the serum. SVHRP significantly reversed the previous harmful effects of 6-OHDA in early-stage PD model. These findings indicate that SVHRP may contribute to neuroprotection by preventing biochemical and ultrastructure damage changes which occur during early-stage PD.
Animals ; Antioxidants ; metabolism ; Corpus Striatum ; Disease Models, Animal ; Dopaminergic Neurons ; drug effects ; Malondialdehyde ; metabolism ; Mesencephalon ; cytology ; Mitochondria ; metabolism ; ultrastructure ; Neuroprotective Agents ; pharmacology ; Oxidative Stress ; Oxidopamine ; Parkinson Disease ; drug therapy ; Peptides ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Scorpion Venoms ; pharmacology ; Superoxide Dismutase ; metabolism