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PubMed2004

[Distribution of NMDAR1 and subunits (alpha1 and alpha3) of GABAA receptor in the cerebellar cortex of adult rhesus macaques].

OBJECTIVE: To investigate the distribution of NMDAR1 and subunits (alpha1 and alpha3) of Immunohistochemistry and GABAA receptors in the cerebellar cortex of adult rhesus macaques. METHODS: Nissl staining were used. RESULTS: (1) NMDAR1 immunoreactivity was prevalent in the endoplasma of Purkinje and dendrites of molecular layer, and moderate in glia, but was very weak in the stellate cells in the molecular layer and granule cells. In addition, cerebellar nuclei were also strongly stained; (2) The immunostaining pattern of subunit of GABAA alpha1 receptor was similar to that of NMDAR1, but more distinctive than NMDAR1 in stellate cells; (3) Immunoreactivity of subunit (alpha3) of GABAA receptor was also prevalent in the endoplasma of Purkinje cells and dendrites. The glia and the neurons of the cerebellar nucli were intensively stained. (4) The rates of Purkinje cells containing NMDAR1, and subunits of GABAA alpha1 and alpha3 were (90.0 +/- 2.1)%, (83.0 +/- 2.3)%, and (78.0 +/- 1.8)%, respectively. Conclusion NMDAR1 and subunits (alpha1 and alpha3) of GABAA receptors are widely distributed in the cerebellum of adult rhesus macaques. These receptors may play an important role in maintaining the complicated function of the cerebellar.

Animals↗
PubMedDate not supplied

Cell proliferation and apoptosis during histogenesis of the guinea pig and rabbit cerebellar cortex.

Cell proliferation and apoptosis are essential for development of the nervous system. In this study we have investigated the histogenesis of the cerebellar cortex in guinea pig (a precocial species) and rabbit (an altricial species) at different stages of pregnancy and postnatal life. Proliferating cells were identified after labeling with antibodies against the proliferating cell nuclear antigen (PCNA) and/or the Ki-67 antigen. Apoptotic cells were visualized in situ by the TUNEL method and by immunodetection of cleaved caspase 3 and 9. In guinea pigs, both proliferating and apoptotic cells were detected during pre-natal life (E0-E40). Conversely, cell proliferation and apoptosis in rabbits were temporally restricted to early postnatal weeks (P0-P20). In both species cell proliferation was mainly linked to differentiation and migration of the granule cells. In both species, the majority of cells undergoing programmed cell death likely corresponded to granule cells. They were mainly detected in the external granular layer, and were by far more common than previously reported in other locations of the postnatal brain. This study shows that apoptosis is a shared process of cell death during cerebellar development in both altricial and precocial animals, and that there is a direct spatial and temporal correlation between cell proliferation and death in two mammals with different time tables in cerebellar maturation.

Aging↗
PubMed1976

Electron cytochemical localization of gamma-aminobutyric acid catabolism in rat cerebellar cortex.

An electron cytochemical technique is described for the localization of GABA-T, the enzyme which degrades the neurotransmitter GABA, in rat cerebellar cortex. The technique allows ultrastructural demonstration of GABA-T activity by the final deposition of an electron dense formazan precipitate at reaction sites, whilst maintaining adequate ultrastructural preservation for recognition of cellular and subcellular structures. Numerous electron dense precipitates are evident as discrete punctate deposits situated mainly in mitochondria of stellate cells, basket cells and astrocytic glial cells; they are also seen in axonal or dendritic profiles at some synaptic junctions. The technique enables the first cytochemical demonstration of the mitochondrial localization of GABA-T activity in nervous tissue to be presented. It establishes that GABA-T is present in supposed GABA neurones, in pre- or post-synaptic endings, or both, of presumed inhibitory synapses and in glial cells which may be associated with these synapses. From this seemingly ubiquitous distribution, functional aspects of GABA-T in these cells is considered.

4-Aminobutyrate Transaminase↗
PubMed1993

Developmental profile of inositol 1,4,5-trisphosphate 3-kinase in rat cerebellar cortex: light and electron microscopic immunohistochemical studies.

Developmental expression and intracellular distribution of inositol 1,4,5-trisphosphate 3-kinase in the rat cerebellar cortex were studied immunohistochemically. Immunoreactivity appeared first at postnatal day 1 in the rostral region of the cerebellum and by day 15 had extended throughout the whole cerebellum, being localized in the Purkinje cell layer. Shortly after the expression of the enzyme in each Purkinje cell, the labelling showed a tendency to accumulate in the dendrites in a fine granular pattern. Electron microscopy revealed that immunoreactivity was present in the Purkinje dendritic trunks with accentuation in the distal segments during the early postnatal period, thereafter becoming concentrated in the dendritic spines at later developmental stages. Labelling was associated mainly with the plasmalemma, including the postsynaptic densities and open coated vesicles, and the subplasmalemmal vesicles of the smooth endoplasmic reticulum. Immunoreactivity was also evident in the perisomatic processes of immature Purkinje cells, which are transient projections synapsing with climbing fibers. In developing Purkinje axons, immunoreactivity was accentuated in the distal segments, associated with the plasmalemma and synaptic vesicles. These results suggest that inositol 1,4,5-trisphosphate 3-kinase is involved in the dendritic arborization and subsequent spine synaptogenesis of Purkinje cells, and that the developing presynaptic nerve endings of these cells are another functional site for the enzyme.

Aging↗
PubMed1986

[Cytochemical research on the matrix activity and status of the histone component of the neurocyte chromatin in the rat cerebellar cortex during postnatal differentiation].

Evident differences in the ammoniacal silver staining pattern of histones were demonstrated for neurones of different layers of adult rat cerebellar cortex. These differences were formed during postnatal differentiation. It has been also shown for Purkinje and granular cells that time-course of age-dependent changes in histone staining are not coincident with that for template activity of these cells.

Aging↗
PubMed1981

Endogenous peroxidatic activity in the cerebral and cerebellar cortex of normal adult rats.

There are at least three sources of endogenous peroxidatic activity that are present in both the cerebral and the cerebellar cortex. All three sources, being neuronal, astrocytic or hemoglobin-dependent, may obscure the interpretation of studies using exogenous horseradish peroxidase. The activities are to a variable extent influenced by fixation. From the present results DAB-incubation of cryostate sectioned brain appears to be an acceptable method for histochemical demonstration of the mitochondrial cytochrome chain enzymes.

Animals↗
PubMed1975

Organization of climbing fibre projections to the cerebellar cortex from trigeminal cutaneous afferents and from the SI face area of the cerebral cortex in the cat.

1. In cats anaesthetized with pentobarbitone, the projection of climbing fibres (CFs) to the cerebellar cortex from trigeminal cutaneous branches and from the face area of the sensorimotor (SI) cortex was mapped, using the technique of laminar field potential analysis. 2. The CF projections from both the trigeminal nerve and the SI face area were found to be localized to the same cerebellar folia, viz. chiefly the ipsilateral lobule HVI, with a small overlap on to the adjacent folia of lobule V and crus Ia of HVIIA. Frequently a projection from the superficial radial nerve to part or all of this area, was also found. 3. A correspondence in the distribution and amplitudes of CF potentials evoked at most points by stimulation of the trigeminal nerve and the SI cortex was found. This implies a convergence of afferents from these two sources at or before the inferior olive. 4. In more than half of the cats, a small area of the cerebellar hemisphere was found, in which contralateral as well as ipsilateral trigeminal stimulation would evoke CF potentials. Usually inputs from the superficial radial nerve and the SI cortex also converged upon this area. 5. The organization of CF projections from trigeminal and superficial radial nerve afferents to the cerebellar hemisphere was found to occur in the same 'patchy' pattern of somatotopy that has been described for spinal nerve inputs to the anterior lobe. 6. One constant factor was found in the pattern of organization of CF projections to this area from cutaneous afferent nerves. That is, only the afferents from overlapping areas of skin projected to a given recording point: no instance of CF projections from trigeminal branches innervating discontinuous skin areas was observed.

Animals↗
PubMed2002

[Comparative morphological analysis of neuron populations in ganglion layer of rodent cerebellar cortex].

The characteristics of basophilic substance distribution, linear dimensions and Purkinje cell (PC) density per unit of gyrus length in ganglion cell layer of cerebellar cortex were studied in ecological-morphological groups of small burrow rodents. Polymorphism specificity of neuron populations in ganglion cell layer was demonstrated in regard to degree of chromophilia of neuron cytoplasm which is characterized by obvious prevalence of normo- and hyperchromatic cells in all PC populations. The correlation between average values of PC body profile area, density of neurons distribution in cell population and the degree of animal adaptation to their environment was analyzed.

Animals↗
PubMed1982

Decreased synaptic areas on Purkinje spines in the cerebellar cortex of the mutant Japanese quail, Coturnix coturnix japonica.

'Dark frayed feather nervous disorder' (dn) is a neurological mutation in quails in which the cerebellar cortex is abnormally organized. Purkinje cells are not aligned in a single row and show hypoplasia of the dendrites. The synapses between the parallel fibers and the spines of the Purkinje cell dendrites were examined with the technique of serial sections in electron microscopy. The postsynaptic thickenings were obviously decreased in the mutant quail despite the same density and size of dendritic spines of Purkinje cells. In addition, ectopic spines and postsynaptic differentiations free of parallel fibers were not found on the dn Purkinje cell. Because of the poor dendritic arborization, the total number of spines and the total synaptic area are, therefore, reduced in the dn Purkinje cell. According to the results obtained the dn mutant genetic locus is considered to affect primarily Purkinje cells.

Animals↗
PubMed2004

Induction of NO-synthase and acetaldehyde dehydrogenase in neurons of human cerebellar cortex during chronic alcohol intoxication.

Induction of NO-synthase and acetaldehyde dehydrogenase in Purkinje cells, basket-like neurons, and microvascular endothelium of human cerebellar cortex was detected in patients with chronic alcohol intoxication. It was hypothesized that the neuromodulating effect of NO is associated with mechanisms protecting neurons from toxic effects of ethanol and acetaldehyde.

Adult↗
PubMed1985

Organization of the cerebellar cortex viewed by scanning electron microscopy.

An improved method of preparing central nervous system tissue for examination in a scanning electron microscope is described. In cerebellar cortex, the precise distribution of synaptic junctions on Purkinje cell bodies, as well as complex arrangements of neurites in the glomeruli of the granule cell layer, are directly visualized. The method also provides views of glial cell processes investing brain surfaces, blood vessels and neurons. The principal advantage of a scanning electron microscopic study is that relationships between cells in the brain can be seen directly instead of inferred from laborious serial reconstructions or other more complex and indirect anatomical methods.

Animals↗
PubMed1993

Total numbers of various cell types in rat cerebellar cortex estimated using an unbiased stereological method.

A new and efficient stereological method for estimating the total number of the different cell types in rat cerebellar cortex is presented. The cells have been subdivided into the following categories: Purkinje cells, granule cells, Golgi cells, glial cells in the granular layer, Bergmann glial cells and neurons and glial cells in the molecular layer. The method has been used to estimate the total number of some of the cell types in rats exposed to orally administered toluene at doses of 200, 400 and 800 mg/kg/day for 12 weeks compared with a control group. No statistically significant differences were found between the exposed and non-exposed animals. The described method can be used in a number of both biological and experimental studies. With the use of new stereological methods it is possible to get precise estimates of total cell numbers in a much shorter time than earlier required. This makes it possible to improve the reliability of the final result by increasing the number of cases processed.

Animals↗
PubMed1990

Freeze-fracture scanning electron microscopy and comparative freeze-etching study of parallel fiber-Purkinje spine synapses of vertebrate cerebellar cortex.

The three dimensional surface morphology, topographical arrangement and intramembrane features of parallel fiber-Purkinje spine synapses of teleost fishes and Swiss albino mice cerebellar cortex have been complementarily studied with the scanning electron microscope (SEM) using the freeze-fracture method and with transmission electron microscope (TEM) by means of freeze-etching replica and thin-sectioning techniques. The SEM fractographs revealed for the first time the outer surface morphology of non-synaptic segments and synaptic varicosities of parallel fibers, which showed clusters of spheroidal synaptic vesicles joined by an amorphous substance. Freeze-etching preparations showed an 'en face' view of P face parallel fiber varicosity (presynaptic P face) characterized by a depressed synaptic active zone with exocytotic vesicle sites, round IMPs (7.5-15 nm), and rod particles (38.5-53 nm in length). Conversely the presynaptic E face exhibited a smooth surface, randomly distributed pits and very low density distribution of round IMPs. The P face of Purkinje spine membrane (postsynaptic P face) showed high density distribution of round or ovoid IMPs, 8-18.5 nm in diameter, and rod IMPs up to 79.2 nm in length. IMPs were also observed beneath the postsynaptic membrane (subsynaptic IMPs) corresponding to the localization of postsynaptic density. The E face of Purkinje spine membrane (postsynaptic E face) showed aggregation of round IMPs, 5.6-17.4 nm in diameter, at the synaptic active zone. Some of these IMPs, particularly the large ones, may morphologically represent the glutamate-receptor ion channels complex. The subsynaptic IMPs may correspond to protein kinases. Granular material and fine filaments were observed in the postsynaptic density. A better insight into the topographical relationship between pre- and postsynaptic structures was obtained of flat and invaginated spine synapses and beside a more realistic view of their glial ensheathment. The SEM fractographs and freeze-etching images were compared with corresponding TEM thin sections for orientation and proper identification of pre- and postsynaptic structures.

Animals↗
PubMed1981

Morphological changes in the cerebellar cortex of aging Macaca nemestrina.

The cerebellar cortices in 4, 10 and 20 year of Macaca nemestrina have been examined for the number of Purkinje (P) and granule cells and the deposition of lipofuscin in P cells in relation to aging. Lipofuscin distribution significantly increased with in the P cells in these animals. The number of P cells was significantly reduced, while there were no changes in the number of granule cells. It appears from this and other studies that the Purkinje cells are more prone to aging changes than the granule cells of the cerebellum both in lipofuscin formation and cell loss. Although the precise functional significance of these changes in P cells is not clear, their vulnerability may be related to changes in motor function in old age.

Aging↗
PubMed1990

Immunolocalization of cytosolic aspartate aminotransferase (cAAT) in axon terminals that form synapses in the rat cerebellar cortex. A study at the electron microscopic level.

This study was conducted to determine the ultrastructural localization of cytosolic aspartate aminotransferase (cAAT)-like immunoreactivity in the cerebellar cortex in the rat. The isoenzyme was found both in excitatory and inhibitory axon terminals, but not in the climbing fibers of the molecular layer. These findings suggest that cAAT may have a different role in the excitatory and inhibitory synapses, and that climbing fibers of the molecular layer do not appear to use aspartate as neurotransmitter.

Animals↗
PubMed1995

Effects of prenatal exposure to low dose ionizing radiation on the development of the cerebellar cortex in the rat.

The effects of maternal exposure to a single dose of whole body irradiation (0.5 Gy) on gestational days (GD) 17, 18, 19, or 20 on the development of the cerebellar cortex was examined in the offspring of Sprague Dawley rats at 21 and 28 days postnatally. No gross cerebellar anomalies were observed in the irradiated animals. However, compared to control animals, rat irradiated on each of GD-17, 18, 19 and 20 showed a significantly higher incidence (p < 0.05) of circumscribed cerebellar lesions (CL) distributed in the inner granular layer of the anterior and posterior lobes. These lesions were characterized by a loss of granule cells and atrophied and/or reduced number of Purkinje cells. In 21 days old rats, irradiation on GD-17 resulted in more CL anteriorly (75%) and in the vermis whereas on GD-20, the CL predominated posteriorly (100%) and in the lateral hemispheres. In 28 day old rats, following irradiation on each of GD-17 and GD-20, there was an equal distribution of CL in both the anterior and posterior lobes. However, with irradiation on both GD-17 and GD-20, these CL occurred more frequently in the lateral hemispheres of the anterior lobe, whereas in the posterior lobe they predominated in the vermis. These results suggest that a direct relationship exists between the proliferation, migration, development, and maturation of granule cells and their induction by Purkinje cells. The findings also support the view that both cell death and the regulation of granule cells by Purkinje cells maximize the effective development and organization of the cerebellum.

Animals↗