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PubMed1987

An ultrastructural description of glutamate-like immunoreactivity in the rat cerebellar cortex.

This study provides the first ultrastructural description of glutamate-like immunoreactive neurons and processes in the cerebellar cortex of the rat. Glutamate-like immunoreactivity was seen in parallel fibers, granule cell perikarya, Purkinje cell dendrites, and mossy fiber glomeruli. These data support previous studies that have suggested that granule cells may use glutamate as a neurotransmitter. However, not all granule cells or all parallel fibers were glutamate-like immunoreactive, suggesting that some granule cells may use transmitters other than glutamate. The presence of glutamate-like immunoreactivity in mossy fibers supports the hypothesis that some cerebellar afferent systems may use glutamate as a neurotransmitter.

Animals↗
PubMed1996

Presynaptic localization of a metabotropic glutamate receptor, mGluR4a, in the cerebellar cortex: a light and electron microscope study in the rat.

Localization of a metabotropic glutamate receptor, mGluR4a, was immunohistochemically examined in the rat cerebellum with an antibody, which was produced by using a synthetic peptide corresponding to a C-terminal sequence of rat mGluR4a. Marked mGluR4a-like immunoreactivity (mGluR4a-LI) was seen in neuropil of the molecular layer of the cerebellar cortex. Electron microscopically, mGluR4a-LI was observed in many axon terminals in the molecular layer. These axon terminals showing mGluR4a-LI were filled with round synaptic vesicles and were in asymmetric synaptic contacts most frequently with dendritic spines. The results indicate that mGluR4a are located presynaptically in the parallel fibers arising from the granule cells in the cerebellar cortex.

Animals↗
PubMed1997

Involvement of cerebellar cortex and nuclei in the genesis and control of unconditioned and conditioned eyelid motor responses.

The eyelid motor system of the cat was used here for the study of the kinetic properties of reflex and conditioned lid movements, and of the role played by the cerebellum in the acquisition and/or performance of both types of motor responses. Spontaneous blinks, eyelid reflex responses, eye-guided lid movements and conditioned lid responses were recorded in alert cats in simultaneity with unitary and field electrical activity of cerebellar cortex and nuclear zones related to the eyelid motor system. Results indicate that nuclear unitary activity does not precede unconditioned or conditioned lid responses, but that cerebellar nuclei are directly involved in the performance of the late components of reflex lid movements and in the acquisition of conditioned lid responses.

Action Potentials↗
PubMed1996

Neuronal and glial localization of the GABA transporter GAT-1 in the cerebellar cortex.

THE distribution and neuronal or glial localization of GAT-1, a high affinity GABA transporter, in the cerebellar cortex was analysed by means of double-label immunofluorescence experiments with GAT-1 combined with calbindin D, synaptophysin, or GFAP antibodies. In the Purkinje cell (Pc) layer, prominent synaptic GAT-1-immunoreactivity (IR) was found in the axon terminals of basket cells surrounding the Pc axon hillock. GAT-1-IR was also found in neuronal and glial processes ensheathing Pc somata and dendrites. Numerous immunoreactive fibres and puncta originating from basket and stellate cells, or from Golgi cells, were also detected in the molecular or granular layer, respectively. These observations suggest that GAT-1 is involved in the termination of the action of GABA at the inhibitory synapses of all cerebellar interneurones, primarily of basket cell terminals at the Pc axon hillock. GAT-1 in the astroglial processes presumably plays the additional role of regulating the extracellular concentrations of GABA.

Animals↗
PubMed2005

Morphocytochemical analysis of neuron populations in the ganglion layer of the cerebellar cortex of birds and mammals living in similar habitats.

The neuron populations in the ganglion layer of the cerebellar cortex of birds and mammals living in similar habitats, i.e., the common squirrel and the house sparrow (Sciurus vulgaris and Passer domesticus), living in an air/land habitat, and the swamp beaver (nutria) and domestic goose (Myocastor coypus and Anser domesticus), living in an earth-water habitat, were studied. Morphocytochemical measures were assessed, i.e., the density of Purkinje cells per unit gyrus length and their sizes, staining properties, and protein contents, for neuron populations in the ganglion layer. Assessment of the staining properties of neurons revealed general features in the organization of the ganglion layer of the cerebellum of vertebrates; assessment of protein contents demonstrated specific features typical for particular classes independently of the animals' habitats.

Adaptation, Physiological↗
PubMed1995

Glutamate receptor subunits at mossy fiber-unipolar brush cell synapses: light and electron microscopic immunocytochemical study in cerebellar cortex of rat and cat.

The present study provides a survey of the immunolocalization of ionotropic glutamate receptor subunits throughout the rat and cat cerebellar cortex, with emphasis on the unipolar brush cell (UBC), a hitherto neglected cerebellar cell that is densely concentrated in the granular layer of the vestibulocerebellum and that forms giant synapses with mossy fibers. An array of nine previously characterized antibodies has been used, each of which stained a characteristic profile of cerebellar cells. The UBCs of both rat and cat were strongly immunostained by an antibody against the alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate (AMPA) receptor subunits, GluR2 and GluR3; were moderately immunostained by a monoclonal antibody to kainate receptor subunits, GluR5/6/7; were weakly immunostained by antibodies to NR1 subunits; and were not stained by antibodies to GluR1, GluR4, GluR6/7, KA-2, and NR2A/B. Postsynaptic densities of the giant mossy fiber-UBC synapses were GluR2/3, GluR5/6/7, and NR1 immunoreactive. The other cerebellar neurons were all immunolabeled to some extent with the GluR2/3 and NR1 antibodies. In addition, Purkinje cells were immunopositive for GluR1 and GluR5/6/7; granule cells were immunopositive for GluR5/6/7, GluR6/7, KA-2, and NR2A/B. The Golgi-Bergmann glia was densely stained by GluR1 and GluR4 antibodies, whereas astrocytes of the granular layer were stained by the GluR4 antiserum. Data provided herein may guide further electrophysiological and pharmacological studies of cerebellar cells in general and the UBCs in particular.

Afferent Pathways↗
PubMed1986

Autolysis of the granular layer of the cerebellar cortex in brain death.

In a study of duration of brain death, granular layer autolysis (GLA) of the cerebellar cortex was analyzed in 45 patients who died of acute cerebrovascular diseases (CVDs). Twelve patients who died of causes other than intracranial disease served as controls. Tonsillar herniation occurred in all who died of acute CVDs. More advanced GLA was seen in the central folia adjacent to the central white medullary body of the cerebellum as compared with the peripheral folia. Widespread GLA involving the most of the peripheral folia was found solely in patients in whom brain death had been present over 18 h. Of the 12 control patients, 4 showed GLA only in the central folia. Although GLA of the central folia might develop during immersion fixation of the brain, the alteration of the peripheral folia is assumed to develop in the period of brain death. Widespread GLA extending to the peripheral folia could be a pathological finding characteristic of brain death, where intracranial blood flow could be absent or significantly reduced. Brain death for little less than 1 day would be necessary for GLA to develop.

Adult↗
PubMed1983

[Cerebellar cyst associated with cytoarchitectonic abnormalities in the cerebellar cortex].

The patient, 64-year-old female, had episode of sudden attack of severe vertigo, headache, nausea, and vomiting which lasted for about twenty minutes on May 20th in 1980. She had hypertension, polyp of stomach, diverticuli of duodenum in her past history. Neurological examination on her admission revealed fine horizontal nystagmus on bilateral gaze and slight clumsy movement on left F-N test. On plain skull and cervical X-P, atlanto-occipital fusion and Klippel-Feil syndrome (C2-C3 fusion) were seen. Plain CT scanning revealed a large cystic lesion which extended from the vermis to the left cerebellar hemisphere. No enhanced area was seen. The forth ventricle was seemed to be enlarged. And the left-sided dorsal part of the forth ventricle attached to the cyst. Metrizamide CT cisternogram showed there was no direct communication between them. Angiographically, the vertebrobasilar arteries were noted sclerotic changes and poor vascularities in the left cerebellar hemisphere was noted. On opening the dura during surgery, the left cerebellar hemisphere appeared bulging state and the bilateral cerebellar tonsils were hypoplastic. Outer thin membrane of the cyst was removed. The cyst has no communication with the subarachnoid space as well as with the forth ventricle. The cystic fluid was slightly yellowish, but had no Froin's sign. Reddish-gray color nodular area, which seemed to be similar to mural nodule macroscopically, was noted in the area of inner surface of the cyst. This part was removed. Histological findings of this area showed abnormal architecture with malarranged layer of cerebellar cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebellar Cortex↗
PubMed1994

Immunohistochemical study of ferritin-positive cells in the cerebellar cortex with subarachnoidal hemorrhage in neonates.

Ferritin immunohistochemistry was performed on the cerebellar cortex with subarachnoidal hemorrhage (SAH) in preterm and term neonates, in comparison with anti-glial fibrillary acidic protein (GFAP) for astrocytes and Ricinus communis agglutinin-1 (RCA-1) immunostaining for microglia. The ferritin-positive cells were increased in the cortex with SAH. The predominant cell type which was labeled with antiserum to ferritin in the human cerebellar molecular layer with SAH was the microglia, which were stained with RCA-1 but not with GFAP. Ferritin-positive microglia may be induced by ischemia with vasospasms, and be related to the loss of Purkinje cells.

Cerebellum↗
PubMed1979

Decrease of cyclic GMP in cerebellar cortex by intrastriatal (--)-sulpiride.

Intraperitoneal administration of (--)-sulpiride (12 to 50 mg/kg) produced a dose-related decrease in cGMP content in cerebellar cortex, while the (+)-sulpiride (10 microgram), but not after intracerebellar injection. These findings support the contention that (--)-sulpiride modifies cerebellar cGMP levels through and action on striatal dopamine receptors.

Animals↗
PubMed1993

Real time operations of the cerebellar cortex.

This manuscript reviews a series of experiments which support the notion that the cerebellum and more specifically the cerebellar cortex is principally involved in real time operations required for the regulation of coordinated motor activity. Experiments are reviewed which illustrate: (1) that the climbing fiber inputs to Purkinje cells can induce a short-lasting enhancement of their responses to mossy fiber-granule cell-parallel fiber inputs, (2) that the cerebellum is not essential for the acquisition and performance of the classically conditioned nictitating membrane reflex (NMR) of the rabbit, and (3) that the observations resulting from the microinjection of lidocaine and multiple single unit recordings within the brainstem support the notion that cell populations in this region may participate in establishing the modifications in neuronal interactions required for the acquisition of the conditioned NMR. In addition, preliminary data are shown comparing the capacity of a normal subject and a patient with a massive ipsilateral cerebellar stroke to learn certain tracing tasks and to redraw these learned tracing movements 90 degrees to the orientation of the original image. The data support the notion that the cerebellum is essential, not for the initial learning of the tracing movement, but rather for performing the learned movement with the required rotation of the original image.

Animals↗
PubMed1997

Local field potential oscillations in primate cerebellar cortex during voluntary movement.

Sustained oscillations of 13-18 Hz were observed in local field potentials (LFPs) in the cerebellar cortex of a behaving monkey. These oscillations, which appeared to be generated in the granular cell layer, were particularly prominent in the paramedian lobule. The oscillatory activity decreased during drowsiness or extreme arousal and occurred most often when the animal was immobile but alert. In a task requiring the animal to move the arm approximately 1 s after an auditory cue, the oscillations stopped some 150-200 ms after the cue, resumed 200-300 ms later, and stopped again 50-100 ms before movement onset. This modulation pattern was observed with consistency only when the animal responded reliably to the auditory cue. The results suggest that the cerebellum could be involved in some higher level of integration particularly during complex sensorimotor behavior.

Animals↗
PubMed1991

Immunocytochemical localization of synaptophysin on the smooth-surfaced tubular membranes present in nerve terminal and preterminal areas in the rat cerebellar cortex.

The distribution of synaptophysin, a major protein of the synaptic vesicle membrane, was immunocytochemically examined in the rat cerebellar cortex. A monoclonal antibody against synaptophysin recognized the epitope to be present in the presynaptic membranous structures including synaptic vesicles, presynaptic membrane, coated vesicles, and vacuoles of endocytotic origin. In the nerve terminal as well as preterminal areas, the antibody labeled the smooth-surfaced tubular membranes which were located in the relatively interior parts of these areas and consistent in size and appearance with the short tubules comprising the thinner parts of the axonal reticulum. However, the antibody did not stain the short tubular membranes, though similar in appearance to the above, which existed right below the axolemma in the preterminal and nerve terminal areas. The results are discussed with special reference to the precursor membrane compartments of synaptic vesicles.

Animals↗
PubMed1985

Stimulatory effect of neonatal beta-estradiol treatment on aspartate-aminotransferase activity within rat cerebellar cortex.

The effect of neonatal beta-estradiol treatment on the Aspartate-aminotransferase (Asp-T) activity within rat cerebellar cortex has been studied using a semi-quantitative histochemical technique. The Asp-T, localized chiefly at the level of nerve fiber-like structures in the molecular layer as well as around the perikaryon of Purkinje neurons, is significantly stimulated after estrogenization. The nerve fibers localized in the molecular layer were the Asp-T cerebellar structures more remarkably influenced by beta-estradiol treatment.

Animals↗
PubMed1992

Calcitonin gene-related peptide in afferents to the cat's cerebellar cortex: distribution and origin.

In the present study, the distribution and origin of calcitonin gene-related peptide (CGRP) were analyzed in the cat's cerebellum. Following incubation in an antibody generated against rat CGRP and processing with the peroxidase anti-peroxidase (PAP) technique, CGRP immunoreactivity (IR) is found in profiles that have morphological characteristics of both simple and complex mossy fibers. However, all mossy fibers are not CGRP-positive. Further, CGRP-IR mossy fibers have a heterogeneous distribution in the cerebellum. In the vermis, the majority of immunoreactive profiles are in lobules VII, VIII, and the dorsal folia of IX. In anterior vermal lobules, only scattered terminals, located primarily at the apex and along the shoulder of the folia, are present. Laterally, CGRP-IR mossy fibers are located in the paramedian lobule, paraflocculus, and crus II. No CGRP fibers or varicosities are observed in any of the cerebellar nuclei. However, CGRP-positive cell bodies are scattered throughout the nuclear neuropil. A double label technique revealed that CGRP-IR mossy fibers arise from neurons located in the lateral reticular nucleus, external cuneate nucleus, inferior vestibular nucleus, and basilar pons. The present findings, taken together with previous data, indicate that cerebellar afferents are chemically heterogeneous. The findings of the present study suggest that precerebellar nuclei that give rise to the mossy fibers that contain CGRP have the potential for playing a complex role in modulating circuitry in the cerebellar cortex of the cat.

Animals↗
PubMed1976

The development of the cerebellar cortex of the Syrian hamster, Mesocricetus auratus. Foliation, cytoarchitectonic, Golgi, and electron microscopic studies.

Although a number of investigations of abnormalities of cerebellar development have been carried out in the hamster, no detailed Golgi or ultrastructural studies of cerebellar development in this species have been reported. This report describes the development of the hamster cerebellar cortex from birth (day 0) through postnatal day 78, as studied by light, Golgi, and electron microscopic methods. Foliation patterns correlate with the expansion of the cerebellar layers and of total cerebellar area. Cytologic and morphologic development of the major cerebellar cell types--Purkinje, Golgi, basket, stellate, granule, and Bergmann glial cells--correlate with those of other species, such as the rat and mouse. Electron microscopic observations at selected developmental ages allow identification and classification of synapses in the early postnatal hamster. Parallel fiber and climbing fiber synapses are already present at birth. Although synaptogenesis probably continues through the first two postnatal months, all major cell types have developed initial synapses by postnatal day 6, at a time when little cellular maturation has occurred. By using gestational rather than natal age, close developmental correlations between hamsters and rat and mouse are possible. Since the gestational period of the hamster is only 16 days, the hamster cerebellum is less mature at birth than that of either the rat or mouse. Thus, the hamster is a convenient animal in which to investigate the effects of various procedures on early cerebellar development.

Animals↗
PubMed1991

Auditory responses in the posterior vermis of the cat: the buried cerebellar cortex.

Although an auditory area has been found over the exposed area of lobules VI-VIII in the posterior cerebellar vermis of the cat, there has been little information on its buried portion. This point should be of some concern, since very little of the brain tissue in lobules VI-VIII of the cerebellar cortex is exposed. We have systematically explored the posterior vermis with long electrode tracks and compared auditory responses recorded from neurons within the granule cell layer in the folial crown with those in the buried cortex. There was a similarity between neural activities recorded from the exposed surface area and those from the buried portion both in the temporal discharge pattern of neurons to sound and in the spatial distribution pattern of auditory responses.

Acoustic Stimulation↗