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A Fasolo

Publications and source records attributed to A Fasolo.

At least 37 records · Page 2Linked to original sources
PubMed1999

Transregulation of erbB expression in the mouse olfactory bulb.

Previously, we have shown that erbB-3 expression is restricted to the ensheathing cells of the olfactory nerve layer, while erbB-4 is found in the periglomerular and mitral/tufted cells of the olfactory bulb and in cells coming out from the rostral migratory stream of the subependymal layer. In the present work, we have treated adult mice with zinc sulfate intranasal irrigation and analyzed erbB-3 and erbB-4 expression in the deafferented olfactory bulb. Following treatment, olfactory axons undergo degeneration, as indicated by the loss of OMP expression in the deafferented olfactory bulb. The thickness of the olfactory nerve layer is reduced, but the specific intensity of erbB-3 labeling in the remaining olfactory nerve layer is increased with respect to control. Interestingly, following deafferentation, erbB-4 immunoreactivity decreases specifically in cell types that normally make synaptic contacts with primary olfactory neurons in the glomeruli, i.e. periglomerular and mitral/tufted cells. Partial lesion of the olfactory epithelium allows regenerative axon growth of olfactory neurons to the olfactory bulb. Following olfactory axon regeneration, erbB-3 and erbB-4 immunoreactivity in the olfactory bulb is similar to control. Thus, like tyrosine hydroxylase, the down regulation of erbB-4 expression in the periglomerular cells is reversible.

Administration, Intranasal↗
PubMed1998

ErbB-3 and ErbB-4 expression in the mouse olfactory system.

The interplay between neuregulins and the ErbB receptor family has a pivotal role in the development of several tissues, including the nervous system, and is maintained in the adult olfactory system where extensive plasticity and neurogenesis are retained. In the present work we show the immunohistochemical localization of ErbB-3 and ErbB-4 in the olfactory system of adult normal and lesioned mice. The expression of ErbB-3 is demonstrated to be restricted to the ensheathing cells of the olfactory nerve and to a few substentacular cells of the olfactory epithelium (OE). ErbB-3 staining circumvents the glomeruli but is never observed inside them or elsewhere in the adult olfactory bulb. Conversely, ErbB-4 immunoreactivity is found in all the periglomerular and mitral/tufted cells of the olfactory bulb (OB) and to a minor extent in the olfactory neurons and basal cells of the OE. Interestingly enough, cells coming out from the rostral migratory stream of the subependymal layer (SEL), as well as isolated cells in the granule cell layer, possibly migrating cells, strongly stained for ErbB-4 expression. Lesions of the olfactory epithelium have been performed by unilateral intranasal irrigation with ZnSO4 and 3 weeks after the irrigation, the olfactory bulbs were analyzed for olfactory marker protein (OMP), tyrosine hydroxylase (TH), ErbB-3 and ErbB-4 expression. In the deafferented OB, the drastic loss of immunoreactivity for OMP was accompanied by a strong reduction of ErbB-3 expression. Most of the deafferented dopaminergic interneurons switched off TH expression. In the deafferented periglomerular and mitral/tufted cells ErbB-4 expression was turned off and down, respectively. No differences were noted at the granular cell layer level in the deafferented OB with respect to control. Taken together our results suggest that, in normal conditions, neuregulins are involved in the survival of the ensheathing cells of the olfactory nerve through ErbB-3 activation and in the functional activity of postsynaptic neurons through ErbB-4 activation.

Animals↗
PubMed1998

Carnosine-like immunoreactivity in astrocytes of the glial tubes and in newly-generated cells within the tangential part of the rostral migratory stream of rodents.

In the nervous system, the aminoacylhistidine dipeptide carnosine (beta-alanyl-L-histidine) has been shown to be expressed in the olfactory receptor neurons and in brain astrocytes. Using immunocytochemical techniques, we report here a dense carnosine-like immunoreactivity in the subependymal layer of the rodent forebrain. Since the subependymal layer involves two distinct compartments (astrocytic cells forming glial tubes and newly-generated cells of the rostral migratory stream, here organized to form chains contained within the glial tubes [Brannon Thomas L. et al. (1996) Glia 17, 1-14; Jancovski A. and Sotelo C. (1996) J. comp. Neurol. 258, 112-124; Lois C. et al (1996) Science 271, 978-981; Peretto P. et al. (1997) Brain Res. Bull. 42, 9-21]), we investigated in detail the cellular distribution of carnosine-like immunoreactivity in this area. By using double labelling techniques with antisera raised against carnosine and specific markers of glial tubes or chains of migrating cells, we show that carnosine-like immunoreactivity is associated with both the compartments. On the other hand, unlike markers of the rostral migratory stream, carnosine-like immunoreactivity was not observed in isolated, migrating cells located outside the subependymal layer, which spread through the olfactory bulb in a radially-oriented manner. This suggests that carnosine is transiently expressed by cells of the rostral migratory stream when moving in the tangentially-oriented part of the migration route. Moreover, we investigated the distribution of carnosine-like immunoreactivity in the postnatal rat forebrain and found that it is detectable in the subependymal layer only starting from the third postnatal week, although it is well known that the dipeptide is present in the olfactory receptor neurons since the embryonic day 16 [Biffo S. et al. (1992) J. chem Neuroanat. 5, 5162]. Taken together, these results show that camosine, other than abundantly present in astrocytes of the glial tubes, is associated to the tangential part of the rostral migratory stream.

Animals↗
PubMed1998

Intranasal fluticasone propionate reduces ICAM-1 on nasal epithelial cells both during early and late phase after allergen challenge.

BACKGROUND: Allergen specific nasal challenge (ASNC) is an optimal method to study the pathophysiological mechanisms sustaining the allergic inflammation and in particular the adhesion molecule system, which is involved in cellular infiltration of nasal mucosa. Topical steroids have been accepted as a highly effective anti-inflammatory therapy for allergic rhinitis. OBJECTIVE: The aim of this double-blind placebo- controlled study was the evaluation of clinical and cytological parameters, including ICAM-1 expression on nasal epithelial cells, after a 4 week treatment with nasal fluticasone propionate (200 microg/daily) or placebo, using the model of ASNC. METHODS: Twenty allergic rhinitics underwent nasal challenge before and after treatment. The following parameters were evaluated: (i) nasal symptoms (rhinorrhoea, itching, sneezing, obstruction), (ii) inflammatory cells (eosinophils and neutrophils), (iii) ICAM-1 expression on nasal epithelial cells at baseline, 30 min (early phase) and 6 h (late phase) after ASNC. RESULTS: Fluticasone propionate was capable of reducing: (i) clinical symptoms during both early (P<0.001) and late phase (P<0.04), (ii) eosinophil (P<0.002) and neutrophil (P<0.001) infiltrate during late phase, and (iii) ICAM-1 expression on nasal epithelial cells during both early (P < 0.01) and late phase (P < 0.03). CONCLUSIONS: The present results demonstrate that fluticasone propionate exerts a significant action on early and late phase clinical events following specific nasal challenge, reducing also the cellular influx during the late phase. This event is likely due to the modulation of ICAM-1 expression on epithelial cells.

Adolescent↗
PubMed1998

Prenatal differentiation of mouse vomeronasal neurones.

The vomeronasal organ (VNO) subserves basic chemosensory functions in rodents, mainly related to sexual behaviour. In order to understand early stages of the VNO structural maturation, we have undertaken an immunocytochemical analysis of the VNO of fetal mice. Our results demonstrate that Olfactory Marker Protein (OMP), a marker of differentiated chemosensory cells, is already expressed in vomeronasal neurones and their fibres projecting to the accessory olfactory bulb during the last week of gestation. However, in contrast to the adult, where its expression is restricted to the medial sensory neuronal component of the VNO, during fetal development OMP is also present in cells located in the lateral non-sensory epithelial component. Some other markers of nasal chemosensory neurones, such as GAP-43/B-50, Protein Gene Product 9.5 (PGP 9.5) and carnosine are also transiently expressed in this ectopic site. These results indicate that (i) significant morphological and biochemical maturation of the VNO is achieved before birth; (ii) transient cell populations, sharing the biochemical profile of the vomeronasal chemosensory receptors, occur in ectopic areas during fetal development.

Animals↗
PubMed1998

Deafferentation up-regulates the expression of the mGlu1a metabotropic glutamate receptor protein in the olfactory bulb.

Chemical lesion of olfactory neuroepitheium induced an up-regulation of the mGlu1a metabotropic glutamate receptor protein in the olfactory bulb, as shown by Western blot analysis. At 2 days after the lesion, the increase in the receptor protein was associated with an increase in mGlu1a mRNA levels; in contrast, at longer times after the lesion (16 days), mRNA levels were reduced in spite of the high expression of the receptor protein, perhaps as a result of product-inhibition of mGlu1 gene expression. Immunohistochemical analysis showed that the increase in mGlu1a induced by olfactory denervation was confined to the glomeruli, which occupy the external portion of the olfactory bulb. Within these structures, mGlu1a receptors are mainly localized on the distal dendrites of mitral cells, which are innervated by the glutamatergic axons of the olfactory nerve. These results demonstrate that the expression of mGlu1a receptors is up-regulated in response to glutamatergic deafferentation, supporting a role for this particular receptor subtype in the physiology of synaptic transmission.

Amino Acid Sequence↗
PubMed1998

Ranakinin, a naturally occurring tachykinin, stimulates phospholipase C activity in the frog adrenal gland.

We have previously shown that the frog adrenal gland is innervated by a dense network of fibers containing ranakinin, one of the endogenous tachykinins in the amphibian Rana ridibunda, and we have found that ranakinin stimulates in vitro corticosteroid secretion by frog adrenal tissue. To elucidate the mechanism of action of ranakinin on the frog adrenal gland, we investigated the effect of ranakinin on cAMP formation and polyphosphoinositide metabolism. Incubation of frog adrenal explants with various tachykinins, including ranakinin, substance P, neurokinin A, or neurokinin B, did not produce any significant modification of cAMP concentrations. In contrast, ranakinin induced a time- and dose-dependent stimulation of inositol phosphate formation with a concomitant decrease in membrane polyphosphoinositides. Pretreatment of the tissue slices with the phospholipase C inhibitor U-73122 or with pertussis toxin completely abolished the stimulatory effect of ranakinin on inositol phosphate formation. Prolonged administration of U-73122 to perifused frog adrenal explants markedly attenuated the ranakinin-evoked stimulation of corticosterone and aldosterone secretion. Taken together, these data indicate that in the frog adrenal gland, ranakinin has no effect on the adenylyl cyclase system, but enhances polyphosphoinositide hydrolysis. The stimulatory action of ranakinin on inositol phosphate formation and corticosteroid secretion is mediated through activation of a phospholipase C positively coupled to a pertussis toxin-sensitive G protein.

Adrenal Cortex Hormones↗
PubMed1998

Cytochemistry of neurotransmitters: from statical analysis to the understanding of dynamic processes.

In the past thirty years, cytochemical methods have allowed neuroscientists to identify and localize neuroactive molecules (neurotransmitters and neuropeptides), their receptors and their synthetic enzymes, and have advanced the understanding of many neuronal functions. Classic methods (histochemical and immunohistochemical techniques) have been used extensively to draw neurochemical maps in adult and developing nervous systems. As a consequence, many neuroactive molecules have become specific biochemical markers for neuronal systems. Double labelling techniques have greatly contributed to the discovery of the coexistence of two or more chemical compounds in the same cell. The in situ hybridization technique has recently become a productive addition to the tools available to the neuroscientist, especially when combined with immunocytochemistry to correlate mRNAs and protein expression. Even today, innovative roles for neurocytochemistry continue to be found. The newest approaches based on RT-PCR (reverse transcriptase-polymerase chain reaction) promise levels of sensitivity never reached before in in situ studies, and can provide simultaneous expression/functional data at the single-cell level.

Animals↗
PubMed1997

Identification of the glial cell types containing carnosine-related peptides in the rat brain.

The cellular localization of carnosine-like immunoreactivity was investigated in the adult rat forebrain and in glial cell cultures obtained from newborn rat brain. Using double staining methods, we showed that in vivo carnosine-like immunoreactivity was occurring in a large number of both glial fibrillary acidic protein (GFAP)-positive astrocytes and 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNP)-positive oligodendrocytes. In vitro, the carnosine-immunoreactive staining was restricted to a subpopulation of completely differentiated oligodendrocytes, whereas no reaction was detected in immature oligodendrocytes and in astrocytes. These observations could have profound physiopathological implications considering the role suggested for carnosine and related peptides as endogenous antioxidants, free radical scavengers and anti-glycating agents of the central nervous system (CNS).

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1997

The cytosolic phosphoprotein stathmin is expressed in the olfactory system of the adult rat.

Stathmin is a cytosolic protein expressed particularly in the developing nervous system, whose phosphorylation is correlated with the action of multiple extracellular stimuli regulating cell proliferation and differentiation. In this study, we used an antibody that specifically recognizes the carboxyterminal region of stathmin to analyze the distribution of this protein in the olfactory system of adult rats, and found a high and selective immunoreactivity in immature olfactory receptors of the olfactory neuroepithelium and in cells of the rostral migratory stream. These results reveal an expression of stathmin in regions of the adult nervous system characterized by striking structural plasticity and cell renewal, suggesting that this protein could play a role in the differentiation of newly generated cell populations.

Animals↗
PubMed1997

Glutamatergic deafferentation of olfactory bulb modulates the expression of mGluR1a mRNA.

Glutamate (Glu) released by olfactory nerve axons acts on postsynaptic ionotropic and metabotropic glutamate receptors expressed by principal neurones and interneurones of the olfactory bulb (OB). Using ZnSO4 lesioning of the rat olfactory mucosa and semiquantitative RT-PCR, we examined the effect of removal of the glutamatergic input to the OB on the expression of mGluR1a, mGluR1b and GluR1 mRNAs. Two days after lesioning, mGluR1a mRNA levels in OB increased by 45%. At this time, the expression of tyrosine hydroxylase (TH) mRNA, which is strictly dependent on olfactory nerve input, was still unchanged. In contrast, 16 days after lesioning, deafferented OB exhibited a decrease in both mGluR1a (-30%) and TH (-40%) mRNAs. GluR1 and mGluR1b mRNA levels were not affected at either time point. These results suggest that alterations in glutamatergic input to OB selectively modulate the expression of the mGluR1 splicing form possessing a longer C-terminal domain.

Animals↗
PubMed1997

Characterization of pars intermedia connections in amphibians by biocytin tract tracing and immunofluorescence aided by confocal microscopy.

Biocytin, recently introduced in neuroanatomical studies, was used as a retrograde tract tracer in combination with immunofluorescence in order to analyse the neurochemical characters of some central neuronal projections to the pars intermedia in two amphibian species, the anuran Rana esculenta and the urodele Triturus carnifex. After biocytin insertions in the pars intermedia, neurons became retrogradely labelled in the suprachiasmatic hypothalamus and the locus coeruleus of the brainstem in both species. Some scattered biocytin-labelled neurons were observed in the preoptic area. Moreover, working on the same sections, immunofluorescence revealed a number of codistributions and, in some cases, colocalization in the same neurons of biocytin labellings and immunopositivity for (1) tyrosine hydroxylase in the suprachiasmatic hypothalamus and the locus coeruleus of Rana and Triturus, (2) gamma-aminobutyric acid in the suprachiasmatic hypothalamus of Rana and Triturus and (3) neuropeptide Y in the suprachiasmatic hypothalamus of Rana. The specificity of such colocalizations was fully confirmed using dual-channel confocal laser scanning microscopy analysis.

Afferent Pathways↗
PubMed1997

Glutamate receptors in the olfactory bulb synaptic circuitry: heterogeneity and synaptic localization of N-methyl-D-aspartate receptor subunit 1 and AMPA receptor subunit 1.

In this study, we analysed the molecular heterogeneity and synaptic localization of the N-methyl-D-aspartate receptor subunit 1 and the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor subunit 1 in the olfactory bulb glomerular synaptic circuitry. Semiquantitative reverse transcriptase polymerase chain reaction showed that approximately 40% of the N-methyl-D-aspartate receptor subunit 1 messenger RNA splice variants contain the N1 exon, which conveys specific functional properties on the channel. In other forebrain and hindbrain regions that we examined, the ratio of the N1-containing (receptor subunit 1(1XX)) to N1-lacking (receptor subunit 1(0XX)) N-methyl-D-aspartate receptor subunit 1 messenger RNAs varied considerably. The cellular and subcellular distribution of N-methyl-D-aspartate receptor subunit 1 and AMPA receptor subunit 1 was investigated with antibodies generated against the C-terminal domain of the individual subunits [Petralia R. S. et al. (1994) J. Neurosci. 14, 667 696; Wenthold R. J. et al. (1992) J. biol Chem. 267, 501 507]. Both N-methyl-D-aspartate receptor subunit 1 and AMPA receptor subunit 1 were localized to the postsynaptic density of asymmetric synapses established by olfactory receptor neuron terminals with the dendrites of mitral and tufted cells. Not all of these synapses, however, were labelled. These results are consistent with the notion that glutamate is the neurotransmitter at the olfactory nerve to mitral and tufted cell synapses, and suggest a high heterogeneity in the expression of the postsynaptic glutamate receptors.

Animals↗
PubMed1997

Newly-generated cells from the rostral migratory stream in the accessory olfactory bulb of the adult rat.

Cell proliferation in the accessory olfactory bulb of the adult rat was analysed after systemic injection of 5-bromo-2'-deoxyuridine, detected immunocytochemically at different survival times and compared with proliferating cell nuclear antigen immunostaining. As previously described in the main olfactory bulb, local cell proliferation was absent or very limited. By contrast, starting from 15 days after bromodeoxyuridine administration, many immunoreactive nuclei were present in the granular layer, and to a lesser extent, in other layers of the accessory olfactory bulb. This suggests that the newly-generated cells are migrating elements of the rostral migratory stream which are known to reach the olfactory bulb in 15 days. By immunocytochemical detection of the polysialylated isoform of the neural cell adhesion molecule, a weakly-adhesive cell-surface molecule expressed by newly-generated/migrating cells of the rostral migratory stream, we found a high number of immunoreactive cells in the different layers of the accessory olfactory bulb. Most of these cells were observed in the granular layer and showed the morphology of migrating neuroblasts. Some immunoreactive cells displaying neuronal morphology were also detected in the external plexiform and glomerular layers. Double labelling experiments demonstrated that these cells are newly-generated cells. These results demonstrate the occurrence of newly-added cells in the accessory olfactory bulb of the adult rat, which likely correspond to the neuronal precursors originating from the rostral migratory stream. This could be relevant since the accessory olfactory bulb of rodents plays an important role in the hard wiring of a simple olfactory memory system for sexual pheromones.

Animals↗
PubMed1997

Glial tubes in the rostral migratory stream of the adult rat.

In the central nervous system cell migration is usually restricted to developmental periods and occurs mainly radially, following the radial glia. Nevertheless, in the subependymal layer of the adult rodent forebrain tangential migration of newly generated neuronal precursors directed to the olfactory bulb, which follow a well-defined pathway without dispersion, has been recently demonstrated. In the present study, by using light microscopic immunocytochemistry for glia-associated antigens (glial fibrillary acidic protein, S-100 and vimentin), and conventional electron microscopy, we observed a dense mesh-work of astrocytic cells and processes throughout the subependymal layer of the adult rat. These cells were organized to form tangentially oriented glial tubes in the subependymal layer of the lateral ventricle and in its rostral extension to the olfactory bulb. Glial tubes were particularly evident within the rostral extension and were widely intercommunicating. Using markers for the proliferating/ migrating cells of the rostral migratory stream (5-bromo-2'-deoxyuridine, PSA-NCAM, class III beta-tubulin), we provide evidence that long chains of PSA-NCAM/beta-tubulin-positive, newly generated cells are consistently observed inside the glial tubes. These results demonstrate the existence of a peculiar glial organization within the subependymal layer of the adult rat, consisting of long astrocytic tubes that likely represent a new type of glial guidance, accounting for the tangential migration of a high number of cells along their restricted pathway, to the olfactory bulb.

Animals↗