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PubMed1993

Distribution of calcium binding protein mRNAs in rat cerebellar cortex.

The distribution of three calcium binding protein mRNAs in the rat cerebellar cortex was investigated using alkaline phosphatase labelled specific antisense oligodeoxynucleotide probes. Calbindin D28k mRNA was detected in the Purkinje cells, parvalbumin mRNA was located in the Purkinje cells and also in basket/stellate cells of the molecular layer. Calretinin in contrast was found only in the granule cell layer. Use of multiple alkaline phosphatase (AP)-labelled oligodeoxynucleotides resulted in an increase in signal strength and reduced detection time with no increase in background staining indicating the utility of these enzyme labelled probes for non-isotopic in situ.

Animals↗
PubMed1980

On the origin of the climbing fibres of the cerebellar cortex.

Unitary climbing fibre activity has been systematically recorded in the rabbit cerebellar cortex at the level of the Purkinje cell layer every 100 micron along the longitudinal axis of the folium. In one group of animals, spontaneous activity was identified in 197 out of 204 (96.6%) explored layers, and was uninterruptedly present up to 2,400 micron along the folia. In a second group of animals, stimulating electrode were placed in the inferior olive and it was found that spontaneous or evoked climbing fibre activity was absent in only 19 out of 422 explored layers: 377 (89.3%) showed a spontaneous and 396 (93.8%) a short latency evoked activity. If some limitations of the method are considered, it can be concluded that all Purkinje cells receive climbing fibre innervation from cells of the inferior olive. The present experiments support the conclusion that the inferior olive is the unique source of climbing fibres.

Action Potentials↗
PubMed1987

The location and orientation of mitotic figures during histogenesis of the rat cerebellar cortex.

The location and orientation of mitotic spindle fibers in the developing cerebellar cortex was examined in rats. In both the transverse and sagittal planes, the mitotic spindle apparatus of cells in the superficial region (EGL-S) was generally oriented perpendicular to the pial surface, whereas that of cells in the deeper aspects (EGL-D) was oriented parallel. The mitotic frequency of cells in the EGL-S was 2- to 6-fold greater than was that in the EGL-D. The mitotic spindle arrangement of dividing cells located adjacent to Purkinje neurons, and presumed to be Bergmann glia, was always perpendicular to the pial surface. Autoradiographic studies revealed DNA synthesis in both the EGL-S and EGL-D. Mitotic cells do not migrate from the EGL-S to the EGL-D, as evidenced by disruption of the cytoskeletal matrix with vinblastine sulfate. Our results suggest that the orientation of the spindle apparatus may play an important role in the emergence of the precise geometry characteristic of the adult cerebellum, and could signify that the phenotypic fate of neural cell precursors is determined prior to the onset of overt differentiation.

Animals↗
PubMed2004

Development of stellate and basket cells and their apoptosis in mouse cerebellar cortex.

Stellate and basket cells in the molecular layer (ML) of the cerebellar cortex proliferate within the white matter (WH) during development. Developmental neuronal death has been documented on granule cells but has not been demonstrated on other GABAergic neurons. We investigated the migration and the cell death of stellate/basket cells further in glutamic acid decarboxylase 67/green fluorescent protein (GFP) knock-in mouse in which every GABAergic neuron was identified by its GFP fluorescence. Analyses were made in the first three postnatal weeks. In the WM, GFP-positive cells were abundant on postnatal day (P) 5-15 but scarce in P21. Stellate/basket cells increased in number in the ML until P15, corresponding to the growth of the ML. Administration of 5-bromo-2'deoxyuridine (BrdU) at P2-8 labeled many cells in the WM within 1h. After BrdU administration at P5, many BrdU-labeled GFP-positive cells were observed in the WM and the internal granular layer at P7, and in the ML at P9. These results support the proliferation of stellate/basket cells in the WM and their migration to the ML. Apoptosis of GABAergic interneurons was demonstrated in the ML and WM during the first two weeks. Their apoptotic loss will contribute to the adjustment of neuron number or elimination of any improper populations.

Animals↗
PubMed1996

Selective distribution of multiple protein kinase C isoforms in mouse cerebellar cortex.

An immunohistochemical study concerning the distribution of protein kinase C isoforms, a lipid-regulated serine/threonine kinase essential for signal transduction, was performed in mice cerebellar cortex, with particular emphasis on the localization of -iota and -lambda isozymes. By the means of immunoblotting analyses we detected the presence of 11 PKC subspecies in whole cerebellar extracts. Immunoreactivity on cryostat sections revealed, using polyclonal and monoclonal antibodies, that a few isoforms were widely but discretely distributed in all three cortical layers (molecular, granular and Purkinje cells) whereas other isozymes were present in a limited neuronal compartment. Overall, the distribution of several isoforms was in agreement with data obtained by other authors using rat cerebellum. As far as -iota and -lambda isozymes were concerned, we found them abundantly expressed in endothelial cells. Moreover, protein kinase C-lambda was also present in the body of Purkinje cell, conceivably associated with a 200-kDa neurofilament component. In all, these results hint at the possibility that in the cerebellar cortex at least some protein kinase C isoforms are involved in functions other than signal transduction at the synaptic level.

Animals↗
PubMed1998

[Structural organization and Lugaro neuron connections in the cat cerebellar cortex].

Two types of intermedial Lugaro cells are distinguished in the cat cerebellum: fusiform (horizontal, vertical and obliquely oriented at angles 60-70 to longitudinal axis of folia cerebelli at different levels of granular layer) and those with triangular somata, sparsely branching dendrites and small number of spines. Both fusiform and triangular neuron axons do not stretch out beyond the borders of cerebellar cortex and may be thought of as recurrent interneurons as they contain GABA and glycine. Lugaro cells form numerous contacts almost with all cortical nervous elements: piriform (Purkinje) and Golgi cells, granular and basket neurons, parallel and mossy fibres and even unipolar, (brush) cells. At light microscopic level they are represented as axosomatic and axodendritic contacts. Lugaro cells are the only cerebellar cortical interneurons with dendritic arborizarion oriented in horizontal plane in contrast to vertical orientation of the other interneurons of cerebellar cortex.

Animals↗
PubMed1987

Chronic alcohol consumption reduces the cortical layer volumes and the number of neurons of the rat cerebellar cortex.

Past work showed that chronic alcohol consumption induces massive degeneration in the rat cerebellar cortex. In order to provide details of these effects, the cortical cell numbers and the cerebellar layer volumes were studied in adult rats fed alcohol for 1, 3, 6, 12, and 18 months and compared with respective age-matched controls. Significant decreases of granular and molecular layer volumes were found after 3 and 6 months of alcohol feeding, respectively. No significant differences were found in the Purkinje cell layer volume. Neuron countings showed that granule cells and molecular layer interneurons were the earliest and most severely affected populations. A decrease in the number of Purkinje cells was observed only after 18 months of alcohol consumption and Golgi cells were not significantly reduced. Thus, we concluded that cerebellar neurons have a selective vulnerability to alcohol which might alter the balance between excitatory and inhibitory limbs of the cerebellar circuitry.

Alcoholism↗
PubMed1985

Impaired development of cerebellar cortex in rats treated postnatally with alpha-difluoromethylornithine.

alpha-Difluoromethylornithine specifically and irreversibly inhibits the enzyme ornithine decarboxylase. Ornithine decarboxylase catalyses the initial step in the synthesis of polyamines, which are thought to play an essential role in growth and development of mammalian tissues. The current study examined the effects of alpha-difluoromethylornithine on the ontogenic development of the rat cerebellar cortex. Animals injected daily with alpha-difluoromethylornithine on postnatal days 1-21 suffered a deficit in the number of granule cells and many of the remaining granule cells became trapped in the molecular layer during migration. Purkinje cells were also scattered throughout the molecular layer and their mean diameter was 38% smaller than in controls. In general, the cerebellar cortex of alpha-difluoromethylornithine-treated rats failed to progress much beyond the stage of development reached in control rats during the first postnatal week. These effects of alpha-difluoromethylornithine were already clearly visible at 10-15 days of age. The final size of the cerebellum as a whole and of individual folia was markedly subnormal. These data indicate that polyamines play an obligatory role in cerebellar neurogenesis and histogenesis.

Animals↗
PubMed1995

Neurotrophin receptor proteins immunoreactivity in the rat cerebellar cortex as a function of age.

The influence of age on immunohistochemically demonstrable neurotrophin receptor proteins (p75, trkA-, trkB-, and trkC-proteins) was studied in the cerebellar cortex of Wistar male rats aged 3 (young), 12 (adult) and 24 (old) months. The number of Purkinje neurons displaying p75, trkA- and trkC-like proteins immunoreactivity (IR), as well as the intensity of p75 and trkA-like protein IR, were significantly reduced in aged rats in comparison with 3 and 12-month-old rats. The intensity of trkC-like protein in the cytoplasm of Purkinje neurons remained unchanged for all the period studied. Moreover, no significant age-dependent changes were observed in the density of p75 or trkC-like proteins IR in the granule neurons layer. The molecular layer showed faint p75 IR which decreased as a function of age. No immunolabelling for neuronal trkB-like proteins was observed, but trkB- and trkC-like proteins IR was found in non-neuronal cells. These results suggest that cerebellar cortex neurons are responsive to and/or dependent upon different neurotrophins. Moreover, the age-dependent impairment in the expression of some neurotrophin receptors in Purkinje neurons, but not in the granule neurons, lends support to a role for neurotrophins in cerebellar aging.

Age Factors↗
PubMed2004

Cerebellar cortex lesions in cases with subtentorial neoplastic changes.

The aim of the study was to perform neuropathological examinations of the brains of children and adults with various types of neoplasms situated in the subtentorial area. In view of the varied opinions on the central nervous system (CNS) lesions in the course of neoplastic diseases, it was interesting to analyze the cerebellar cortex damage. The study material included fifteen primary tumors in children and fourteen tumors in adults. In the former, two primary and three metastatic tumors were treated with irradiation and chemotherapy (ChTh). In the remaining cases such a treatment was not employed because of the clinical course of the disease. Among adult cases, eight primary and six metastatic tumors were observed. In all metastatic cases irradiation and ChTh were used, other primary tumors were untreated because of the short follow-up period. In all the investigated cases, cerebellar cortex damage was observed. Except for lesions surrounding the neoplastic proliferation, two types of changes were found: one with a prevalence of Purkinje cell loss was similar to the first type of paraneoplastic cerebellopathy, while in the other a granular cell layer lesions predominated. In the entire material the changes were particularly severe in the children, mostly in those with the damage of the granular cell layer, contrary to the prevalent opinions that the CNS damage in the course of neoplastic diseases is more common in adults. Another interesting observation was that the changes did not correlate with the type of tumor and the employed therapy. The results of this study may be interesting for clinicians who perform neurological examinations in pediatric long-survivors of subtentorial tumors.

Adolescent↗
PubMed1991

Synaptosomal protein kinase C subspecies: A. Dynamic changes in the hippocampus and cerebellar cortex concomitant with synaptogenesis.

The expression of protein kinase C (PKC) subspecies in synaptosomes prepared from a number of adult brain regions was compared. Cerebral cortical and thalamic/striatal synaptosomes were found to express three peaks of enzyme activity upon hydroxyapatite chromatography, corresponding to the type I(gamma), type II(beta), and type III(alpha) subspecies. Synaptosomes prepared from either the hippocampus or the cerebellar cortex, however, contained only two major peaks, corresponding to the alpha- and beta-subspecies, with barely detectable levels of the gamma-subspecies, even though these tissue areas were enriched in the latter enzyme. When the ontogenic pattern of hippocampal synaptosomal PKC subspecies was examined, it was found that at postnatal day 7, significant quantities of the gamma-subspecies were present and that this subspecies reached its peak levels at around postnatal day 14, before steadily declining to its adult level. Similar changes were observed also for the gamma-subspecies in cerebellar cortex synaptosomes. The dynamic changes in the synaptosomal PKC subspecies take place at a critical period in the development of the rat brain, concomitant with an active period of synaptogenesis, suggesting that it may play a role in synaptogenesis.

Aging↗
PubMed1993

Immunolocalization of meprobamate-like molecules in rat cerebellar cortex.

The localization of meprobamate-like (MPB-like) molecules in the cerebellar cortex of the rat was investigated with the peroxidase-antiperoxidase (PAP) immunocytochemical method using an antiserum raised in rabbits. The positive immunoreaction for MPB in several nervous structures and in the wall of blood capillaries suggest the presence of endogenous MPB-like molecules.

Animals↗
PubMed1994

Histochemical study of mitochondrial enzymes in cerebellar cortex of macular mutant mouse, a model of Menkes kinky hair disease.

The cerebellar Purkinje cells in the hemizygote of the macular mutant mouse contain numerous abnormal mitochondria which show a marked decrease in cytochrome c oxidase activity. Using histochemical methods we studied the activity of other mitochondrial enzymes, such as NADH diaphorase and succinic dehydrogenase, in the cerebellar cortex of this mutant mouse. Such activities were markedly increased in the Purkinje cells, especially in the soma and stem dendrite, from 10 days after birth in the hemizygote as compared with findings in normal littermates. These results were considered to be due to an increased number of abnormal mitochondria.

Animals↗
PubMed1983

Supraspinal cell populations projecting to the cerebellar cortex in the turtle (Pseudemys scripta elegans).

Neuronal cell populations giving rise to cerebellar projections in the turtle, Pseudemys scripta elegans, were analysed following injections of horseradish peroxidase into the cerebellar cortex. The most prominent retrograde cell labeling occurred bilaterally within the caudal rhombencephalon and especially in the ventral portion of the inferior reticular field. Based on the structural parameters of the labeled cells (size, dendritic tree), their location and laterality of projection, attempts were made to identify cell groups similar to the inferior olive, the lateral funicular (reticular) nucleus and the perihypoglossal complex of other vertebrates. There were some labeled neurons within the descending and principal trigeminal nuclei, but few if any within the dorsal column nuclear complex. Cerebellar projections on the other hand clearly arose from the n.vestibularis inferior and n.vestibularis dorsolateralis on both sides. While there was little evidence for labeled cells located in a similar position as the pontine nuclei of higher vertebrates, a conspicuous number of neurons were observed in meso-diencephalic regions. Confirming the findings of Reiner and Karten (1978) characteristic accumulations of cells were seen in the nucleus opticus tegmenti, in the ipsilateral mesencephalic tegmentum and lateral and ventral to the ipsilateral nucleus pretectalis. Additional neurons were found in the periventricular hypothalamus, the nucleus of the fasciculus longitudinalis medialis and in the n.interstitialis of flm on both sides as well as in the red nucleus.

Afferent Pathways↗
PubMed2002

Structure-function relations of two somatotopically corresponding regions of the rat cerebellar cortex: olivo-cortico-nuclear connections.

The somatotopical organization of the climbing fiber input to the paravermal region of lobulus simplex (LS, lobule Vla) was charted in the cerebellar cortex of anaesthetized rats. From medial to lateral in LS, zones a2, c1, c2 and c3 were identified. Forelimb responses were found in both LS and the paramedian lobule (PML) and simultaneous recordings from the c1 zone in both lobules showed that trial-by-trial fluctuations in climbing fiber field size evoked by ipsilateral forelimb stimulation did not occur in synchrony, suggesting that the two parts of the same zone are not closely linked by their climbing fiber input. Electrophysiological mapping in combination with a double fluorescent axonal tracing strategy (mix of Fluoro-Emerald and green beads, and mix of Fluoro-Ruby and red beads) revealed that the two parts of the c1 zone receive climbing fiber input from similar territories in the medial and dorsal accessory olives, but that only 4% of the total population of labelled cells have axons that branch to supply climbing fiber afferents to both regions of cortex. The corticonuclear output of the two parts of the zone was found in mainly overlapping regions of the transitional region between the anterior and posterior divisions of nucleus interpositus. Overall, the results suggest that the olivocerebellar and corticonuclear projections of cerebellar zones are similarly organized in rat and cat, implying that the function of individual zones is conserved between species.

Action Potentials↗
PubMed1988

Histochemical and cytochemical localization of acetylcholinesterase in the cerebellar cortex of the chicken.

The localization of acetylcholinesterase (AChE) was studied in the cerebellar cortex of the crossbred trembler chickens by means of histo- and cytochemical methods. No essential differences between the crossbred normal and the crossbred trembler chickens were observed. The common results were as follows: Under a light microscope AChE activity was predominantly evident in the molecular layer, and secondly in the granular layer. AChE was ultrastructurally distributed principally in the cisternae of rough endoplasmic reticulum (ER) and in a part of nuclear envelope of the Purkinje, the Golgi and some of the basket and granule cells, and in a portion of the sacculus of the Golgi apparatus of the Purkinje cell only. In dendrites and the initial axon of the Purkinje cells the smooth ER also showed AChE activity. Although dendritic terminals of the Golgi cells contained AChE reaction products, the axon terminal did not. Some of the afferent terminal fibers forming the cerebellar glomerulus exhibited weakly a positive AChE reaction, while others in the vicinity did not show any AChE activity at all. However, the enzyme reaction product was localized in the intercellular spaces between a presynaptic afferent terminal and the postsynaptic granule cell dendritic terminals in the glomerulus. In addition, AChE activity was found in the form of spots in the intercellular spaces of both molecular and granular layers.

Acetylcholinesterase↗
PubMed1987

Focal synaptic potentials due to discrete mossy-fibre arrival volleys in the cerebellar cortex.

The previously described direct and relayed projections of periodontal afferents to the cerebellar cortex have been examined in detail by extracellular field-potential analysis. Advantage is taken of the very small temporal dispersion of the afferent volleys to permit identification of the presynaptic spike potential of mossy fibres, the subsequent synaptic potential and the firing of granule cells. Changes in form of the presynaptic potential with depth are compared with published descriptions of presynaptic potentials elsewhere. The negative synaptic potential in the granular layer is shown to have a positive aspect in the molecular layer. Granule-cell firing can, under some conditions, yield a population spike interrupting the synaptic potential wave. Records are presented showing all-or-none complex waves, which appear to be single glomerular potentials, not previously described in the mammalian cerebellum. Their distinction from cellular spike potentials is emphasized.

Afferent Pathways↗