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G Bernocchi

Publications and source records attributed to G Bernocchi.

At least 19 recordsLinked to original sources
PubMed2006

Monoamine receptors and immature cerebellum cytoarchitecture after cisplatin injury.

The experimental model of cisplatin treatment provides the opportunity to identify the precise function of the neurotransmitters in some crucial events of brain development, and their interactions or modulatory roles. The serotonin and noradrenaline monoamines influence the formation of the cerebellar cortex circuitry. In this study we found changes in the expression of the serotonin and noradrenaline receptors after a single injection of cisplatin in 10-day-old rats. The growth of Pc dendrites was early altered in lobules VI-VIII of cerebellum vermis. In these lobules, at postnatal day (PD) 17, the cisplatin-induced increase of the serotoninergic receptor 5-HT2AR, a factor that inhibits Pc dendrite growth by acting post-synaptically, occurred in all cerebellar layers, suggesting also alteration of granule cell proliferation and migration. The decreased labelling of beta l adrenergic receptor (beta1AR) in the soma of some Pc at PD11 can be correlated with the altered expression of glutamate receptors and GAD65 (glutamic acid decarboxylase) of and on Pc we have previously described [Pisu, M.B., Guioli, S., Conforti, E., Bernocchi, G., 2003. Signal molecules and receptors in the differential development of cerebellum lobules. Acute effects of cisplatin on nitric oxide and glutamate system in Purkinje cell population. Dev. Brain Res. 145, 229-240; Pisu, M.B., Roda, E., Avella, D., Bernocchi, G., 2004. Developmental plasticity of rat cerebellar cortex after cisplatin injury: inhibitory synapses and differentiating Purkinje neurons. Neuroscience 129, 655-664]. Moreover, beta1AR seems to be the key factor in the cerebellar reorganization between PD17 and PD30. The expression of this receptor was maintained in the molecular layer (ML), in particular in the inhibitory interneurons, despite their different distributions. The labelling of 5-HT1AR in the ML areas lacking Pc dendrite branches could contribute to the recovery phase of the cerebellar cytoarchitecture in cisplatin-treated rats. In general these findings should be taken into consideration in therapeutic interventions for developmental CNS disorders with a morphological basis.

Animals↗
PubMed2006

Reorganization of the rat cerebellar cortex during postnatal development following cisplatin treatment.

We examined the effects of the antitumor agent cisplatin on the development and plasticity of cerebellar cytoarchitecture. Since knowledge of the parallel and climbing fiber-Purkinje cell system is important in order to determine the architectural basis of cerebellar function, we used immunofluorescence for vesicular glutamate transporters (VGluT1 and VGluT2) to evaluate the trend of synaptogenesis of parallel and climbing fibers on Purkinje cells in the cerebellum vermis after a single injection of cisplatin to 10-day-old rats, i.e., during a crucial period of cerebellar development. The temporal and spatial patterns of VGluT1 and VGluT2 immunoreactivity after the early cisplatin injury provided evidence that remodeling of excitatory afferents and Purkinje cell dendrites occurs. After an early slow down of Purkinje cell dendrite growth, 7 days following the treatment, the extension of the molecular layer was reduced, as was parallel fiber innervation, but VGluT1 immunoreactive fibers contacted Purkinje cell dendrite branches extending within the external granular layer. VGluT2 immunopositive climbing fiber varicosities were still largely present on the soma and stem dendrites of Purkinje cells. Twenty days after the cisplatin injection, the thickness of the VGluT1 immunopositive molecular layer was reduced. VGluT2 climbing fiber varicosities were found on the remodeled Purkinje cell dendrites, as in controls, although at a lower density. Alterations in the immunoreactivity for polysialic acid neural cell adhesion molecule (PSA-NCAM) during the recovery phase suggest that this molecule plays a fundamental role not only during development, but also in the reorganization of neuroarchitecture. The changes were restricted to the neocerebellar vermis and were likely dependent on the different timing of lobule formation. The results of these investigations reveal the existence of vulnerability windows of the cerebellum to exposure to experimental or environmental cytotoxic agents during a critical period in development.

Animals↗
PubMed2004

Developmental plasticity of rat cerebellar cortex after cisplatin injury: inhibitory synapses and differentiating Purkinje neurons.

A single injection of cisplatin, a cytostatic agent, (5 microg/g body weight) in 10-day old rats leads later to the reorganization of the cerebellar cortex in lobules VI-VIII of the vermis. Double immunofluorescence reaction for glutamate receptor (GluR)2/3, a ionotropic glutamate receptor that labels postsynaptically Purkinje neurons, and glutamic acid decarboxylase (GAD)65, an isoform of the GABA synthesis enzyme that labels presynaptically inhibitory terminals in the molecular layer, were employed. Less-differentiated Purkinje cells were present in rats treated on postnatal day (PD)11 at the top of lobule VI and in lobules VII-VIII, in comparison with the deep zones of the same lobules and lobule III. The changes were interpreted as due to loss of trophic factors of Purkinje cell growth, e.g. signaling molecules and granule cells. However, we have shown that a remodelling of Purkinje cell dendrites occurred on PD30 (20 days after cisplatin). In fact, despite of the GluR2/3 labeling of the entire Purkinje cell dendrites, the GAD65 immunofluorescent terminals were adjacent to the proximal parts of the dendrite, while they were scarce in the distal dendritic branchlets. The findings were discussed in relation to the changed cytoarchitecture of the cerebellar cortex, which from PD17 to PD30 includes regeneration of the external germinal layer, reorientation of the main dendritic branches and of the Purkinje cell branchlets, and the presence of ectopic cells.

Age Factors↗
PubMed2002

Morphological changes in the frog cerebellar cortex after unilateral section of the statoacustic nerve.

To investigate a possible role of the cerebellum in vestibular compensation that follows a lesion to the vestibular apparatus, the morphological changes of the cerebellar cortex of adult frogs following unilateral statoacustic nerve section was analyzed by means of electron microscopy starting from 3 days after the neurectomy for up to 6 months. On the ipsilateral side, massive abnormality was found in all layers at early postsurgical intervals. This involved both nerve fibers and cell bodies. Fibers often appeared condensed or vacuolated with poorly compacted myelin sheath. Cells had electronlucent and vacuolated cytoplasm to varying extent. Alterations became less conspicuous after 30 days and after 60 days altered nerve cells were no longer present. On the contralateral side, only a few Purkinje and granule cells were affected at early postsurgical stages. This may derive from the fact that, in the frog, some of the vestibular primary afferents reach contralateral cerebellar cortex. At 30 days, alterations had substantially progressed, and at 60 days they involved all the cortical layers. Fiber debris was present in the granular and molecular layers and numerous Purkinje cells were electrondense and shrunken. This lateness in alteration may be a consequence of the prolonged silence of the vestibular nucleus contralateral to the lesion. At 4 and 6 months the tissue architecture was normal.

Animals↗
PubMed2000

Gastrin-cholecystokinin immunoreactivity in the central nervous system of Helix aspersa during rest and activity.

The immunostaining pattern for the peptide gastrin/cholecystokinin 8 (gastrin/CCK8) in the molluscan central nervous system has been considered. The changes in the distribution of gastrin/CCK8 immunoreactivity were analyzed in the neurons of different areas of the cerebral ganglia (mesocerebrum and metacerebrum) and in the buccal ganglia of the terrestrial snail Helix aspersa, during rest and active phases. During the period of inactivity and after one day of activity, there were several immunoreactive neurons in the mesocerebrum and metacerebrum of the snails and in the buccal ganglia, whereas after 7 days of activity the number of labeled neurons decreased. Data suggested a storage of gastrin/CCK8 in the neurons when behavioral activities in which the peptide is involved (such as feeding-related behavior) are suppressed or reduced. The different percentage of gastrin/CCK8 immunoreactive neurons in the left and right mesocerebrum provides information about the activities controlled by these neurons, which could be related to the adaptive evolution and plasticity of the brain in terrestrial pulmonates.

Animals↗
PubMed2000

Development of the anatomical alteration of the cerebellar fissura prima.

The development of the naturally occurring malformation of the cerebellar fissura prima was monitored in rats starting from 4 days of life to the adulthood. The first sign of the malformation was evident at 10 days of life and consisted of an interruption of the pia mater and the fusion of the external granular layers on the two sides of the fissura. Later, nests of apparently mature granule cells could be seen to be encircled by cells of the external granular layer and to be connected to the granule cell layer by thin bridges of cells. Calretinin immunoreactive fibers followed the bridges of cells to reach the ectopic masses of cells. Towards the end of histogenesis and in adult animals, brush cells and Golgi cells were present in the ectopic masses of granule cells. The latter appeared to contribute to the formation of normal glomeruli, as in the orthotopic granule cell layer. In addition, bundles of parallel fibers crossed the boundary between the molecular layers on the two side of the fissure, thus suggesting that parallel fibers can contact Purkinje cells of the opposite folium.

Animals↗
PubMed1999

Mature and developing visual system of Ceratitis capitata (Diptera, Tephritidae): histochemical evidence of nitric oxide synthase in the wild type and the white eye mutant strains.

Nitric oxide (NO) is acknowledged as a messenger molecule in the nervous system. It has a role in the modulation of the chemosensory information and seems implicated also in visual processes and visually guided behaviour of some insects. In the present study, we used two different strains of the medfly Ceratitis capitata (Diptera, Tephritidae), a wild type eye colour and a white eye mutant line, as models to clarify the involvement of NO in the mature and developing visual system. The comparison between the pattern of enzyme histochemical localization of NO synthase (NOS), through NADPH diaphorase (NADPHd) staining, in the optic lobes of the two strains revealed for adults a stronger intensity of reaction in all the neuropiles and the sub-retinic monopolar cell layer of the wild type flies, with respect to the white eye mutant correspondent areas. Anti-NOS immunocytochemistry correlated with these results, underlying reactivity both in fine fibres and varicosities and in cell bodies and supporting the idea of presence of NOS also in the retina of the medfly optic lobes. NADPHd reactivity was present in the first developmental stages of the white eye mutant also, but at lower intensity than wild type, and it decreased in some areas during the transition to adult fly stage both in the wild type and in the white eye mutant. All these observations together indicate that changes in the NO system of C. capitata could be related to the visual information processing, when the visual response or discrimination are altered. Furthermore, NO may be involved in the establishment of the retinal projection pattern and in the control of optic lobes morphogenesis.

Animals↗
PubMed1999

Nitric oxide-containing neurons in the nervous ganglia of Helix aspersa during rest and activity: immunocytochemical and enzyme histochemical detection.

Nitric oxide synthase (NOS) immunoreactivity and staining for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-diaphorase) activity are two cytochemical markers for nitric oxide (NO)-containing neurons. The authors examined the changes in the distribution of NOS immunolabeling and NADPH-diaphorase reactivity in the cerebral and buccal ganglia of the terrestrial snail Helix aspersa during resting and active phases. During inactivity and after 1 day of activity, in the mesocerebrum and metacerebrum of the snails, there were several reactive neurons for both markers; after 7 days of activity, the number of reactive neurons was lower. Opposite results were obtained in the buccal ganglia, in which increased staining and numbers of reactive neurons were present in the active snails (after 1 day and 7 days of activity). Although the staining patterns for the two reactions were similar, colocalization was not always observed. The comparison between inactive and active animals provided a more precise survey of NOS-containing neurons in the snail cerebral ganglia than previously described. Moreover, it suggested that not only is NO involved in distinct nervous circuits, but, as a ubiquitous molecule, it also plays a role in neuroprotection and neuropeptide release.

Animals↗
PubMed1999

Distribution of calretinin-like immunoreactivity in the brain of Rana esculenta.

The distribution of calretinin-like immunoreactivity has been analyzed in the brain of Rana esculenta. Several neurons of nuclei belonging to sensory pathways, subhabenular area and left habenula were immunopositive. Immunoreactivity was present in fibers of motor and sensory pathways, thalamus, tegmentum and isthmus. The immunolabeling pattern partially overlapped that previously described in the rat. However, in comparison with the rat, fewer cells and fibers were immunoreactive and there were less positive brain nuclei. especially in the pallium, septum and striatum, that were totally negative. Taking into consideration that these regions are rather simple in the frog, the presence of calretinin seems to be consistent with the degree of complexity of brain areas and segregation of different nuclei.

Animals↗
PubMed1998

Bioactive peptides and serotonin immunocytochemistry in the cerebral ganglia of hibernating Helix aspersa.

The role of some neuromodulators and neurotransmitters in the functioning of molluskan cerebral neurons and in their metabolic changes during hibernation has been considered. The cerebral ganglion of mollusks is a center for the integration of different inputs from the sensory areas of the head and for the generation of motor command impulses. During hibernation, animals are deprived of many external sensory stimuli and do not have locomotion and feeding. Immunocytochemistry for bioactive peptides (BAPs), such as SP (Substance P), CCK8 (Cholecystokinin 8/Gastrin), CGRP (Calcitonin-Gene-Related Peptide) and ET (Endothelin), and serotonin was performed on cerebral ganglia of active and hibernating Helix aspersa. The distribution of the immunopositivity was analyzed in different cell-containing areas (procerebrum, mesocerebrum, metacerebrum) and in the neuropiles. With all the antibodies raised against peptides, we observed that only a few neurons, mainly of small and medium size, had immunopositivity during the period of activity, the patterns of distribution being quite similar to those previously described in Helix or other gastropods. Fibers and varicosities with BAP immunopositivity were found in the procerebral and central neuropiles and sometimes around neurons. Serotonin-immunopositive neurons, including the giant neuron, were observed in the metacerebrum; numerous fibers and varicosities immunopositive for serotonin were present in the neuropile areas. In hibernating snails, the number of fibers with BAP and serotonin immunopositivity decreased in several areas of the neuropiles. Moreover, an increased number of neurons of the metacerebrum (two-to four-fold) and mesocerebrum (8- to 28-fold) had BAP-like immunopositivity, and the intensity of the immunoreaction for serotonin of the metacerebral neurons was also higher than in the active snails. These results are discussed, taking into account two hypotheses. The first hypothesis assumes that the increased immunocytochemical staining was really linked to accumulation of BAPs and serotonin. The second hypothesis considers that the antibodies for BAPs recognized a preprotein, the synthesis of BAPs being completed during the active period only. Both the hypotheses account for the co-occurrence and co-localization of two or ore peptides and serotonin and stress that the hibernation condition is of interest for studies on the actual function of single neurons in the cerebral ganglia. Finally, the data are consistent with the changes recently found in other markers of the morphological and functional activity of neurons, demonstrating that the neuromodulation and the neurotransmission are slowed during hibernation.

Animals↗
PubMed1998

Immunocytochemical changes of cytoskeleton components and calmodulin in the frog cerebellum and optic tectum during hibernation.

During hibernation, variation in the metabolism of nerve cells occurs. Since the cytoskeleton plays an important role in nerve cell function, we have analyzed the immunocytochemical expression of two cytoskeleton components, i.e. phosphorylated 200 kDa neurofilament protein, and microtubule-associated protein 2 in the cerebellum and optic tectum of hibernating frogs (Rana esculenta) in comparison with active animals. In addition, we have considered the immunocytochemical expression of calmodulin, which is known to be involved in neurofilament phosphorylation. In hibernating animals, there was a decrease in the immunoreactivity for phosphorylated 200 kDa neurofilament protein and microtubule-associated protein 2 of fibers in both the cerebellum and in the optic tectum. In contrast, in the large neurons of the cerebellum, i.e. Purkinje neurons, there was an increase in the immunoreactivity for microtubule-associated protein 2. The changes in the cytoskeleton components were accompanied by a decrease in calmodulin immunoreactivity in the cytoplasm of nerve cells of the cerebellum. All the changes observed are consistent with a low neuronal activity during hibernation, as also indicated by previous microdensitometric and microfluorometric data. This shows a higher degree of chromatin condensation in hibernating animals and suggests that hibernation represents a simple form of neuronal plasticity.

Animals↗
PubMed1997

Glial cell reaction to cis-dichlorodiammine platinum treatment in the immature rat cerebellum.

In this study we have investigated changes in glial cells of the cerebellum of cis-dichlorodiammine platinum (cisDDP)-treated rats. The expression of S-100 protein and glial fibrillary acidic protein (GFAP), taken as markers of glial cell function, was evaluated using immunocytochemical methods. In parallel, immunoreactivity for calbindin, parvalbumin, and phosphorylated 200-kDa neurofilament protein was observed in Purkinje cells as markers for neuronal integrity and activity. Results showed that, although no difference in the immunostaining of S-100 protein between control and treated animals could be observed, an increase in the frequency of GFAP immunoreactive cells was present in cisDDP-treated rats. In Purkinje cells, immunocytochemical expression of calbindin and parvalbumin was decreased after drug treatment. In addition, following immunoreaction for phosphorylated 200-kDa neurofilament protein, the somata of Purkinje cells, which were negative in control animals, were stained in treated rats. These findings suggest that cisDDP does not significantly interfere with pathways of glial cell activity and that the increased number of GFAP positive astrocytes may be due to an activation of glial cells consequent upon neuronal death.

Animals↗
PubMed1995

A re-evaluation of the ultrastructural localization of 5'-nucleotidase activity in the developing rat cerebellum, with a cerium-based method.

The membrane ectoenzyme 5'-nucleotidase converts 5'-AMP into adenosine which, in the nervous tissue, plays an important role as intercellular messenger. Moreover, during histogenesis, 5'-nucleotidase seems to be related to cell proliferation and migration. Conflicting data are reported in the literature about the localization (neuronal or glial) of 5'-nucleotides in the rat cerebellum. In the present report we have analyzed the distribution of 5'-nucleotidase activity with electron microscopy, using a cerium-based method, at different postnatal histogenetic stages (postnatal days (PND) 11, 17, 28). On PND 11 and 17, rims of reaction product outlined the plasma membranes of some neuroblasts in the external granular layer and of parallel fibers and some migrating cells in the developing molecular layer. Positivity was frequently observed on membranes of adjacent neuronal cells and glial processes. Moderate activity was also present on the membranes of granule cells and of mossy fiber rosettes and granule cell dendrites constituting the cerebellar glomeruli within the internal granule cell layer. At PND 28, the reaction product was slightly reduced in some localizations. Cytochemical patterns prove that the cerium-based method is suitable for demonstration of 5'-nucleotidase-specific activity. In fact, a continuous and fine reaction product appears strictly linked to the cell membranes, and no unevenly scattered precipitates can be observed. Data suggest that, during cerebellar histogenesis, 5'-nucleotidase may be involved in the mechanisms of cell migration and proliferation. However, in adulthood, prominent localization of the reaction product on neuronal elements suggests a major role in neuromodulation processes for the enzyme.

5'-Nucleotidase↗
PubMed1995

The cerebral neurons of Helix aspersa during hibernation. Changes in the cytochemical detection of calmodulin, cytoskeletal components and phosphatases.

Some markers of the intracellular systems that regulate neuronal activity and morphology were analyzed in the cerebral ganglion of hibernating snails (Helix aspersa), in comparison with active animals. The immunocytochemical expression of a calcium-binding protein, i.e. calmodulin, and some cytoskeletal components, i.e. 200 kDa phosphorylated neurofilament protein (pNFH), microtubule associated protein 2 (MAP2) and alpha-tubulin were analyzed by the use of a panel of antibodies raised against mammal antigens. Moreover, by enzymatic reactions the Ca(2+)-ATPase and alkaline phosphatase (AIPase) activities were demonstrated. In comparison with the active phase, the hibernation induced an increase in the immunopositivity for calmodulin in all the neurons. The increase may be linked to unmasking of immunoreactive epitopes due to conformational changes of the protein, which in turn may be a consequence of a reduction or absence of binding with calcium ions or of a real increase in the amount of calmodulin in the somata of neurons. In any event, both the hypotheses indicate that neurons have decreased or suppressed the Ca(2+)-dependent mechanisms as also shown by the lower Ca(2+)-ATPase activity. Nevertheless, the AIPase activity, which was localized in the epineural sheat, was not significantly changed during hibernation and this supports that some metabolic activities are preserved in the hibernated animals. Changes in the immunopositivity for cytoskeletal components were found. There was an increase in the epitopes recognized by the mammalian pNF antibody, that concerned both the positivity of the entire cytoplasm of some clusters of metacerebral neurons and the intensity of the reaction. This would be aimed to improve the stability of the somata and primary neurites. Moreover, the decrease of alpha-tubulin and MAP2 immunopositivity, suggests that a disassembly of microtubules have occurred. The findings indicate that the transport of vesicles in the axons is slowed down during hibernation. In fact, research in progress show that the patterns of neurotransmission and neuromodulation are also deeply modified.

Alkaline Phosphatase↗
PubMed1995

Effects of cis-dichlorodiammineplatinum on the molecular layer interneurons of the immature rat cerebellum: a putative role for calcium.

The administration of cis-dichlorodiammineplatinum to rats at 10 days of postnatal life (PD 10) alters the immunoreactivity for parvalbumin of the interneurons of the cerebellar molecular layer at late post-treatment intervals. This can result in, but may be also a consequence of the elevation in the cytosolic calcium concentration. Changes in the intracellular calcium homeostasis may induce damage of the cytoskeletal apparatus and impair growth of the cell processes leading to alteration of the ultrastructure of the cell.

Age Factors↗
PubMed1993

Neuroprotective effects of alpha-dihydroergocryptine against damages in the substantia nigra caused by severe treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.

The effects on the substantia nigra of alpha-dihydroergocryptine (DEK), a drug with strong dopaminomimetic activity, were tested with a severe 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in monkeys. Compared with monkeys treated with MPTP alone, the animals which received DEK plus MPTP showed reduced neuronal death in the substantia nigra. The reactive astrocytes were increased in number. Moreover, several axons which were immunopositive to phosphorylated neurofilament proteins and with features similar to those of control animals were seen in the pars compacta. The findings suggest that DEK preserves neuronal morphology and brain architecture.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1992

Frog hepatocyte modifications induced by seasonal variations: a morphological and cytochemical study.

A correlated morphological and cytochemical approach was employed to study frog hepatocytes in different periods of their annual cycle, including the natural hibernating period. There were considerable changes in the distribution and organization of hepatic glycogen in different phases of the annual cycle, and distribution of organelles as well. The most striking findings were glycogen storage during the prehibernation and hibernation phases, followed by drastic glycogen depletion. Cytochemical staining of a number of enzymes (succinate dehydrogenase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, paranitrophenyl phosphatase, acid phosphatase, and glucose-6-phosphatase) involved in a variety of metabolic pathways, showed various cytoplasmic localizations and differences in intensity of the reaction products as a function of seasonality. Morphological and cytochemical data were interpreted as evidencing different functional requirements during seasonal changes in the frog.

Acid Phosphatase↗