• Applied Microscopy
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• v.50
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• pp.6.1-6.6
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• 2020

The cerebellum is a region of the brain that plays an important role in motor control. It is classified phylogenetically into archicerebellum, paleocerebellum and neocerebellum. The Purkinje cells are lined in a row called Purkinje cell layer and it has a unique dendritic branches with many spines. The previous study reported that there is a difference of synapse density according to the lobules based on large two-dimensional data. However, recent study with high voltage electron microscopy showed there was no differences in dendritic spine density of the Purkinje cell according to its phylogenetic lobule. We analyzed Purkinje cell density in the II, VI and X lobules by stereological modules and synaptic density was estimated by double disector based on Purkinje cell density in the molecular layer of each lobule. The results showed that there was significant difference in the Purkinje cell density and synapse number according to their phylogenetic lobules. The number of Purkinje cell in a given volume was larger in the archicerebellum, but synapse density was higher in the neocerebellum. These data suggest that cellular and synaptic organization of the Purkinje cell is different according to their phylogenetic background.

• Development and Reproduction
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• v.15 no.3
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• pp.205-213
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• 2011

Ethanol treatment during the brain growth spurt period has been known to induce the death of Purkinje cells. The underlying molecular mechanisms and the role of reactive oxygen species (ROS) in triggering ethanol-induced Purkinje cell death are, however, largely unresolved. We undertook TUNEL staining, western blotting assay and immunohistochemistry for the cleaved forms of caspase-3 and -9, with calbindin D28K double immunostaining to identify apoptotic Purkinje cells. The possibility of ROS-induced Purkinje cell death was immunohistochemically determined by using anti-8-hydroxy-2'deoxyguanosine (8-OHdG), a specific cellular marker for oxidative damage. The results show that Purkinje cell death of PD 5 rat cerebellum following ethanol administration is mediated by the activation of caspase-3 and -9. However, unexpectedly, TUNEL staining did not reveal any positive Purkinje cells while there were some TUNEL-positive cells in the internal and external granular layer. 8-OHdG was detected in the Purkinje cell layers at 8 h, peaked at 12-24 h, but not at 30 h post-ethanol treatment. No 8-0HdG immunoreactive cells were detected in the internal and external granular layer. The lobule specific 8-OHdG staining patterns following ethanol exposure are consistent with that of ethanol-induced Purkinje cell loss. Thus, we suggest that ethanol-induced Purkinje cell death may not occur by the classical apoptotic pathway and oxidative damage is involved in ethanol-induced Purkinje cell death in the developing cerebellum.

• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.290-296
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• 1998

Histological changes was investigated in the 4 weeks old rat brain using NMDA (N-methyl-D-asparate) which is capable of mediating excitotoxic events. The changes were occured when the injected NMDA solved in PBS was over $1.0{\mu}g/g$(about 90nM). The necrosis of Purkinje cells in cerebellum and the increasement of coloidal plexus cell number were prevalent. The Purkinje cell number of necrosis were increased according to increasement of amount of injected NMDA. In spite of increasement of degenerated Purkinje cell number, differentiation of new Purkinje cell was not identified because total number of Purkinje cell was not changed. The change of cell number was observed in coloidal plexus cell rather than degeneration of cell. About 5 time increasement was occured. This change may cause increasement of cerebrospinal fluid and the makes mophorogy of brain more round than nomal.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.4
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• pp.355-366
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• 1997

Although cerebellar Purkinje cells display spontaneous electrical activity in vivo and in slice experiments, the mechanism of the spontaneous activity generation has not been clearly understood. The aim of this study was to investigate whether cerebellar Purkinje cells of postnatal rats generate spontaneous electrical activity without synaptic inputs. Dissociated cerebellar Purkinje cells were used for reducing synaptic inputs in the present study. Cerebellar Purkinje cells with dendrites were dissociated from postnatal rats using enzymatic treatment followed by mechanical trituration. Spontaneous electrical activities were recorded from dissociated cells without any stimulus using whole-cell patch clamp configuration. Two types, spontaneously firing or quiescent, of dissociated Purkinje cells were observed in postnatal rats. Both types of cells were identified as Purkinje cells using immunocytochemical staining technique with anti-calbindin after recording. Spontaneously active cells displayed two patterns of firing, repetitive and burst firings. Two thirds of dissociated Purkinje cells displayed repetitive firing and the rest of them did burst firing under same recording condition. Repetitive firing activities were maintained even after further isolation using either physical or pharmacological techniques. Neither high magnessium solution nor excitatory synaptic blockers, AP-5 and DNQX, block the spontaneous activity. These results demonstrate that spontaneous electrical activity of isolated cerebellar Purkinje cells in postnatal rats is generated by intrinsic membrane properties rather than synaptic inputs.

• Biomedical Science Letters
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• v.16 no.4
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• pp.259-264
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• 2010

This study was designed to investigate the effects of nitric oxide on the neuronal activity of rat cerebellar Purkinje cells. Sprague-Dawley rats aged 14 to 16 days were decapitated under ether anesthesia. After treatment with pronase and thermolysin, the dissociated Purkinje cells were transferred into a chamber on an inverted microscope. Spontaneous action potentials and potassium current were recorded by standard patch-clamp techniques under current and voltage-clamp modes respectively. 15 Purkinje cells revealed excitatory responses to $20\;{\mu}M$ of sodium nitroprusside (SNP) and 4 neurons (20%) did not respond to SNP. Whole potassium currents of Purkinje cells were decreased by SNP (n=10). Whole potassium currents of Purkinje cells were also decreased by L-arginine, substrate of nitric oxide (n=10). These experimental results suggest that nitric oxide increases the neuronal activity of Purkinje cells by altering the resting membrane potential and after hyperpolarization.

• 한국전자현미경학회:학술대회논문집
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• 2005.05a
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• pp.116-117
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• 2005

• Korean Journal of Exercise Nutrition
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• v.16 no.2
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• pp.73-84
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• 2012

Thyroid hormones are important for the development of the brain including the cerebellum. In the present study, we investigated the effect of treadmill exercise on the survival of Purkinje neurons and the activation of astrocytes in the cerebellar vermis of hypothyroidism-induced rat pups. On the day of perinatal 14, pregnant rats were divided into two groups (n = 5 in each group): the pregnant control group and the pregnantmethimazole (MMI)-treated group. For the induction of hypothyroidism in the rat pups, MMI was added to the drinking water (0.02% wt/vol), from the day of perinatal 14 to postnatal 49. After delivery, male rat pups born from the pregnant control group were assigned to the control group. Male rat pups born from the MMI-treated group were divided into the hypothyroidism-induction group, the hypothyroidism-induction with treadmill exercise group, and the hypothyroidism-induction with thyroxine (T4) treatment group (n = 10 in each group). The rat pups in the exercise group were forced to run on a treadmill for 30 min once a day for 4 weeks, starting on postnatal day 22. In the hypothyroidism-induced rat pups, motor coordination was reduced and Purkinje cell death and reactive astrocytes in the cerebellar vermis were increased. Treadmill exercise enhanced motor coordination, increased the survival of Purkinje neurons, down-regulated reactive astrocytes, and enhanced brain-derived neurotrophic factor (BDNF) and receptor tyrosine kinase B (TrkB) expressions in the hypothyroidism-induced rat pups. These results suggest that treadmill exercise has beneficial effects in terms of protecting against thyroid dysfunction by increasing T3 and T4 and the related protein, BDNF, as well as TrkB, inhibition on astrocyte activation and the reduction of Purkinje cell loss regarding the cerebellum in hypothyroidism rat pups.

• Molecules and Cells
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• v.20 no.2
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• pp.219-227
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• 2005

Purkinje cell degeneration (pcd) mice are characterized by death of virtually all cerebellar Purkinje cells by postnatal day 30. In this study, we used DNA microarray analysis to investigate differences in gene expression between the brains of wild type and pcd mice on postnatal day 20, before the appearance of clear-cut phenotypic abnormalities. We identified 300 differentially expressed genes, most of which were involved in metabolic and physiological processes. Among the differentially expressed genes were several calcium binding proteins including calbindin-28k, paravalbumin, matrix gamma-carboxyglutamate protein and synaptotagamins 1 and 13, suggesting the involvement of abnormal $Ca^{2+}$ signaling in the pcd phenotype.

• BMB Reports
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• v.51 no.2
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• pp.79-84
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• 2018

Niemann-Pick type C disease (NP-C) is a fatal neurodegenerative disorder caused by a deficiency of NPC1 gene function, which leads to severe neuroinflammation such as astrogliosis. While reports demonstrating neuroinflammation are prevalent in NP-C, information about the onset and progression of cerebellar astrogliosis in this disorder is lacking. Using gene targeting, we generated vascular endothelial growth factor (VEGF) conditional null mutant mice. Deletion of VEGF in cerebellar Purkinje neurons (PNs) led to a significant increase of astrogliosis in the brain of NP-C mice in addition to the loss of PNs, suggesting PN-derived VEGF as an important factor in NP-C pathology. Moreover, replenishment of VEGF in neurons improved brain pathology in NP-C mice. Overall, our data provide a new pathological perspective on cerebellar astrogliosis in NP-C and suggest the importance of VEGF as a therapeutic target for this disease.

• BMB Reports
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• v.56 no.5
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• pp.308-313
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• 2023

Phenotypic features such as ataxia and loss of motor function, which are characteristics of Parkinson's disease (PD), are expected to be very closely related to cerebellum function. However, few studies have reported the function of the cerebellum. Since the cerebellum, like the cerebrum, is known to undergo functional and morphological changes due to neuroinflammatory processes, elucidating key functional factors that regulate neuroinflammation in the cerebellum can be a beneficial therapeutic approach. Therefore, we employed PD patients and MPTP-induced PD mouse model to find cytokines involved in cerebellar neuroinflammation in PD and to examine changes in cell function by regulating related genes. Along with the establishment of a PD mouse model, abnormal shapes such as arrangement and number of Purkinje cells in the cerebellum were confirmed based on histological finding, consistent with those of cerebellums of PD patients. As a result of proteome profiling for neuroinflammation using PD mouse cerebellar tissues, fetuin-A, a type of cytokine, was found to be significantly reduced in Purkinje cells. To further elucidate the function of fetuin-A, neurons isolated from cerebellums of embryos (E18) were treated with fetuin-A siRNA. We uncovered that not only the population of neuronal cells, but also their morphological appearances were significantly different. In this study, we found a functional gene called fetuin-A in the PD model's cerebellum, which was closely related to the role of cerebellar Purkinje cells of mouse and human PD. In conclusion, morphological abnormalities of Purkinje cells in PD mice and patients have a close relationship with a decrease of fetuin-A, suggesting that diagnosis and treatment of cerebellar functions of PD patients might be possible through regulation of fetuin-A.