Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “OLFACTORY NERVE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 865 records · Page 48Linked to original sources
PubMed1993

Expression of p75NGFR in the olfactory system following peripheral deafferentation.

Following chemically induced peripheral deafferentation of the main olfactory bulb, expression of the low affinity receptor for neurotrophins, p75NGFR, was monitored immunohistochemically using monoclonal antibody MAb192. In control animals, p75NGFR expression was localized to the glomerular layer of the main olfactory bulb and deepest one third of the olfactory neuroepithelium. Peripheral lesioning dramatically reduced expression of glomerular p75NGFR while inducing expression of p75NGFR in the olfactory nerve layer. Expression of p75NGFR in the lesioned neuroepithelium was disorganized compared with controls. These observations demonstrate that the maintenance of the peripheral input from the neuroepithelium is critical to expression of p75NGFR in the main olfactory bulb.

Animals↗
PubMed1997

Morphology of interneurons in the procerebrum of the snail Helix aspersa.

Terrestrial snails have a highly developed sense of olfaction. Because the procerebrum has a large number of cells and is located at the entry site of the olfactory nerve into the brain, the structure is thought to have a significant role in the processing of olfactory stimuli. The morphology of the procerebral neurons in the snail Helix aspersa was investigated through intracellular injections of biocytin. No formal categorization of neuronal types was possible, but some cells were seen to have neurites entirely intrinsic to the procerebrum, whereas others had both intrinsic and extrinsic arborizations, and still others had only extrinsic arborizations. These interneurons were previously thought to have arborizations restricted to the procerebral lobe. We demonstrated the extent of the neurite projections outside of the procerebral lobe by making focal injections of biocytin or Neurobiotin into various regions of the cerebral ganglion. This technique revealed subsets of cells that send neurites not only in the ipsilateral ganglion but also through the cerebral commissure into the contralateral cerebral ganglion. Our results demonstrate not only that the procerebral cell population is heterogeneous but also that the procerebrum interacts more directly with the rest of the central nervous system than was formerly believed.

Animals↗
PubMed1995

Organization of the olfactory system in the adult zebrafish: histological, immunohistochemical, and quantitative analysis.

The zebrafish, Danio rerio, is becoming an important model system for developmental studies. We have used a variety of histological techniques to characterize the adult structure of the olfactory system in this teleost to form a base for future developmental work. The olfactory epithelium in this fish contains ciliated and microvillar sensory neurons, microvillar supporting cells, secretory goblet cells, and basal cells, and the adjacent nonsensory epithelium contains ciliated supporting cells. The olfactory bulb is a diffusely organized structure with four laminae: olfactory nerve, glomerular, mixed mitral cell/plexiform, and granule cell layers. These structures and the synapses observed in the olfactory bulb are typical of what is found in other vertebrates. We also examined the distribution of several neurotransmitter markers (tyrosine hydroxylase, neuropeptide Y, dopamine-beta-hydroxylase, and serotonin) in the olfactory bulb. Antibodies to neuropeptide Y, dopamine-beta-hydroxylase, and serotonin labeled fibers in the olfactory bulb and cell bodies in caudal regions of the brain in distributions comparable to other species. Tyrosine hydroxylase immunoreactivity was observed in a set of intrinsic bulb neurons with extensive processes in the glomerular layer. In addition, the structural proteins glial fibrillary acidic protein and vimentin have distributions similar to those in the olfactory bulbs of other animals. Thus, the adult olfactory structures are analogous to the structures in other vertebrate animals in morphology and chemical neuroanatomy. This similarity, along with its numerous advantages for developmental studies, makes the zebrafish a good model for studies of olfaction and forebrain maturation.

Animals↗
PubMed1994

Immunocytochemical localization of mammalian GnRH (gonadotropin-releasing hormone) and chicken GnRH-II in the brain of the European silver eel (Anguilla anguilla L.).

Using specific antibodies for the two molecular forms of gonadotropin-releasing hormone (GnRH) present in the European eel, Anguilla anguilla, (mammalian GnRH, mGnRH, and chicken GnRH II, cGnRH-II), we employed immunocytochemistry to determine the distribution of these two peptides in the brain and in the pituitary. The results indicate that mGnRH and cGnRH-II are localized in different neurons: mGnRH-immunoreactive (ir) perikaria were observed in the olfactory bulbs, the junction between olfactory bulbs and telencephalon (nucleus olfactoretinalis), the telencephalon, the preoptic region and the mediobasal hypothalamus. These cell bodies are located along a continuum of ir-fibers that could be traced from the olfactory nerve to the pituitary. Mammalian GnRH-ir fibers were detected in many parts of the brain (olfactory bulbs, ventral telencephalon, hypothalamus, optic tectum, mesencephalon) and in the pituitary. Chicken GnRH-II-ir cell bodies were detected in the nucleus of the medial longitudinal fasciculus of the midbrain tegmentum, but only scattered fibers could be detected in different parts of the brain. The pituitary exhibited very few cGnRH-II-ir fibers, contrasting with an extensive mGnRH innervation. These results are in agreement with our previous data obtained in the same species using specific radioimmunoassays for mGnRH and cGnRH-II. They demonstrate a differential distribution of the two forms of GnRH in the brain of the eel, as in the brain of some other vertebrate species, and suggest differential physiological roles for the two GnRH forms in the eel. They also provide information concerning the evolution of the GnRH systems in vertebrates.

Anguilla↗
PubMedDate not supplied

Vomeronasal organs and nerves of Jacobson in the human fetus.

The vomeronasal organs and nerves of Jacobson were found on both sides of the nasal septum in a 28-week human fetus. The vomeronasal organ in the human is a tubular structure with an opening into the nasal cavity anteriorly and closed posterior end. The vomeronasal nerve is distributed equally to the medial and lateral aspects of the organ, courses along the nasal septum and goes through the cartilaginous cribriform plate with the olfactory nerve. The cellular configuration of the vomeronasal organ is similar to the olfactory neuroepithelium. No areas of receptor-free epithelium were found in the vomeronasal organs. Intraepithelial blood vessels and mitotic figures were not observed in the epithelium of the vomeronasal organs at 28 weeks. The lack of intraepithelial blood vessels and mitoses may suggest that the vomeronasal organs are undergoing degeneration at 28 weeks of gestation.

Humans↗
PubMed1999

Development of P2 olfactory glomeruli in P2-internal ribosome entry site-tau-LacZ transgenic mice.

Primary olfactory neurons project their axons to the olfactory bulb, where they terminate in discrete loci called glomeruli. All neurons expressing the same odorant receptor appear to terminate in a few glomeruli in each olfactory bulb. In the P2-IRES-tau-LacZ line of transgenic mice, LacZ is expressed in the perikarya and axons of primary olfactory neurons that express the P2 odorant receptor. In the present study, we examined the developmental appearance of P2 neurons, the topographical targeting of P2 axons, as well as the formation of P2 glomeruli in the olfactory bulb. P2 axons were first detected in the olfactory nerve fiber layer at embryonic day 14.5 (E14.5), and by E15.5 these axons terminated in a broad locus in the presumptive glomerular layer. During the next 5 embryonic days, the elongated cluster of axons developed into discrete glomerulus-like structures. In many cases, glomeruli appeared as pairs, which were initially connected by a fascicle of P2 axons. This connection was lost by postnatal day 7.5, and double glomeruli at the same locus were observed in 85% of adult animals. During the early postnatal period, there was considerable mistargeting of P2 axons. In some cases P2 axons entered inappropriate glomeruli or continued to grow past the glomerular layer into the deeper layers of the olfactory bulb. These aberrant axons were not observed in adult animals. These results indicate that olfactory axons exhibit errors while converging onto a specific glomerulus and suggest that guidance cues may be diffusely distributed at target sites in the olfactory bulb.

Aging↗
PubMed1985

Distribution of cholecystokinin-like immunoreactivity in the rat main olfactory bulb.

The anatomical localization of cholecystokinin-like immunoreactivity (CCK-I) within the rat main olfactory bulb was analyzed by using the peroxidase-antiperoxidase immunocytochemical technique. Neurons or neuronal processes containing CCK-I were localized within all laminae of the olfactory bulb except the olfactory nerve fiber layer. A large population of CCK-I neurons, with morphology, size, and distribution corresponding to that of the middle and external tufted cells, was observed within a zone extending from the deep periglomerular region through the superficial one-half to one-third of the external plexiform layer. A smaller number of immunoreactive perikarya were found in the deep external plexiform layer, the glomerular layer, and rarely within the inner plexiform layer. These CCK-I neurons appeared to correspond to internal tufted cells, periglomerular cells, and deep short-axon cells, respectively. Dense CCK-I staining of fibers and terminals was present within the internal plexiform layer and, less densely, within the neuropil of the granule cell layer. In addition, terminal-like CCK-I was localized within layer 1A of the anterior olfactory nucleus, the olfactory tubercle, and the most rostral piriform cortex. This observation provides corroboration for the identification of the principal CCK-I neuron in the rat olfactory bulb as the centrally projecting middle tufted cell. The present results, demonstrating the localization of CCK-I to both local circuit and projection neurons of the olfactory bulb and to terminal-like puncta in the internal plexiform and granule cell layers, suggest that CCK may be significantly involved in olfactory processing at several levels.

Animals↗
PubMed2003

Organization of postsynaptic density proteins and glutamate receptors in axodendritic and dendrodendritic synapses of the rat olfactory bulb.

Glutamate neurotransmission in the olfactory bulb involves both axodendritic synapses and dendrodendritic reciprocal synapses and possibly also extrasynaptic receptors. By using a sensitive immunogold procedure, we have investigated the organization of two synaptic scaffolding molecules, PSD-95 and PSD-93, as well as N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA) receptors, at these heterogeneous glutamate signaling sites. Immunolabeling for PSD-95 and PSD-93 was present in all major types of putative glutamatergic synapse, suggesting that these proteins are essential components of the synaptic signaling apparatus. The linear density and the subsynaptic distribution of PSD-95/PSD-93 gold particles did not differ significantly between axodendritic and dendrodendritic synapses. Antibodies recognizing NMDA and AMPA receptor subunits also labeled asymmetric synapses throughout the olfactory bulb. Immunolabeling for the AMPA receptor subunits GluR2/3 was similar in all types of synapse. In contrast, immunogold signals for the NR1 subunit of NMDA receptors varied significantly among different synapse populations, with olfactory nerve synapses in the glomerular layer showing the lowest labeling intensity. Although the lateral dendrites of mitral and tufted cells have been reported to respond to glutamate, they did not display significant plasma membrane labeling for the NR1 subunit or for PSD-95, suggesting that the physiological effects of glutamate at these sites are mediated by NMDA autoreceptors that are not clustered and occur only at a low density on the dendritic surface. Our quantitative analysis of olfactory bulb synapses indicates that the density of NMDA receptors is not determined by the complement of PSD-95/PSD-93. The latter molecules appear to be expressed in an all-or-none fashion and may form a standard lattice common to different types of glutamatergic synapse.

Animals↗
PubMed2006

Loss of trigeminal sensitivity reduces olfactory function.

The trigeminal and olfactory nerves share overlapping innervation areas in the nasal cavity and seem to work in an interactive way. Loss of olfactory function leads to a decreased trigeminal sensitivity, as shown in anosmic subjects. To report the impact of disturbed trigeminal sensitivity on the olfactory function, we present a patient with unilateral loss of trigeminal function resulting from a meningeoma. Thresholds to a selective olfactory stimulus were elevated by a factor of 64 on the affected side. Recordings of event-related potentials in response to olfactory stimuli showed a significantly reduced response on the affected side. This report indicates that loss of trigeminal function may affect the sense of smell.

Female↗
PubMed1999

Distinctive neuronal organization of the olfactory bulb of the laboratory shrew.

The organization of the main olfactory bulb of an insectivore, the laboratory shrew (Suncus murinus), was studied morphologically. We found particular small spherical regions, nidi, at the border between the glomerular and external plexiform layer (EPL), which were intensely GAD positive, 30-60 microm in diameter, and where no olfactory nerves were seen. Around the nidus small calbindin D28k-positive GABAergic neurons, perinidal cells, were clustered. Furthermore, a distinctive type of newly discovered neurons, which we named tasseled cells, located at the middle of the EPL extended dendrites to the nidus, where their small tuft-like complicated branches made synapses with perinidal cells. The present study showed that the basic components of the olfactory bulb are not necessarily constant in all mammals.

Animals↗
PubMed1999

Differential antigen expression during metamorphosis in the tripartite olfactory system of the African clawed frog, Xenopus laevis.

In the adult African clawed frog, Xenopus laevis, olfactory epithelium is housed in three separate nasal cavities: the principal cavity, the middle cavity, and the vomeronasal organ. The sensory epithelium in each of these cavities has distinct cellular features, and presumed physiological and behavioral functions, which arise during metamorphosis. Most notably, the middle cavity is formed de novo, and the principal cavity is transformed from a larval sensory epithelium with water exposure to an adult olfactory epithelium with air exposure. To understand the cellular nature of this plasticity more clearly, we characterized the staining patterns generated in the olfactory system of X. laevis with a new monoclonal antibody, anti-E7. The olfactory epithelium is first stained with anti-E7 during late embryonic development. Transection of the olfactory nerves during metamorphosis eliminates all staining and indicates that the staining is associated with mature or nearly mature olfactory receptor neurons. The antibody diffusely stains the vomeronasal organ throughout development and in adults. In the larval principal cavity, the olfactory receptor neurons are brightly stained, but this cellular staining is lost after metamorphosis. The mucus from Bowman's glands in the principal cavity, however, is intensely stained in adults. The middle cavity, throughout development and in adulthood, has the same staining characteristics as the larval principal cavity. Thus, the E7 antibody can distinguish the three areas of the olfactory epithelium, allowing measurement of sensory epithelium volume, and serves as an excellent marker for the changes in the sensory epithelium that occur during metamorphosis.

Animals↗
PubMed1991

Functional subdivisions of the olfactory system correlate with lectin-binding properties in Xenopus.

Soybean agglutinin (SBA) is known to selectively label a portion of neurons in amphibian and mammalian primary olfactory systems. Hitherto, no other distinctive features have been found to correlate with the two neuronal populations. Investigating SBA-HRP binding in olfactory mucosa and CNS of Xenopus, we noted that labelled and unlabelled structures can readily be assigned to different olfactory subsystems. The SBA negative one is utilized to detect air-borne odors, whereas major SBA-positive structures serve a role in the perception of water dissolved molecules. Some labelled fibers by-pass the olfactory bulb, traverse the telencephalon and innervate prosencephalic structures. They are considered to be aberrant olfactory nerve fibers, rather than being part of the terminal nerve.

Animals↗
PubMed1995

Uptake and transport of manganese in primary and secondary olfactory neurones in pike.

gamma-spectrometry and autoradiography were used to examine the axoplasmic flow of manganese in the olfactory nerves and to study the uptake of the metal in the brain after application of 54Mn2+ in the olfactory chambers of pikes. The results show that the 54Mn2+ is taken up in the olfactory receptor cells and is transported at a constant rate along the primary olfactory neurones into the brain. The maximal velocity for the transported 54Mn2+ was 2.90 +/- 0.21 mm/hr (mean +/- S.E.) at 10 degrees, which was the temperature used in the experiments. The 54Mn2+ accumulated in the entire olfactory bulbs, although most marked in central and caudal parts. The metal was also seen to migrate into large areas of the telencephalon, apparently mainly via the secondary olfactory axons present in the medial olfactory tract. A transfer along fibres of the medial olfactory tract probably also explains the labelling which was seen in the diencephalon down to the hypothalamus. The results also showed that there is a pathway connecting the two olfactory bulbs of the pike and that this can carry the metal. Our data further showed a marked accumulation of 54Mn2+ in the meningeal epithelium and in the contents of the meningeal sacs surrounding the olfactory bulbs. It appears from our study that manganese has the ability to pass the synaptic junctions between the primary and the secondary olfactory neurones in the olfactory bulbs and to migrate along secondary olfactory pathways into the telencephalon and the diencephalon.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

[Resistance of the slow potential and inhibition of afferent input of the frog olfactory bulb to hypoxia and blockade of synaptic transmission by manganese, cobalt and magnesium ions].

The effects of hypoxia and Mn++, Co++ and Mg++ on the electrical responses of the olfactory bulb to natural stimulation and single direct electric stimulation of olfactory nerve were studied in a frog. The slow potential evoked by natural stimulation and related inhibition of afferent olfactory input proved to be much more resistant to depression of synaptic transmission in the olfactory bulb with any methods used than postsynaptic components of the olfactory bulb orthodromic potential and related postsynaptic inhibition. Slow potentials were recorded after total blockade of synaptic transmission by Mg++ ions. It is concluded that the slow potential and related inhibition of afferent olfactory input are mainly of nonsynaptic nature. It is suggested that the slow potential reflects the depolarization of glial cells in a glomerular layer evoked by accumulation of K+ ions. Possible mechanisms for inhibition of olfactory bulb afferent input are discussed.

Animals↗
PubMed2004

Inhibitory role of endophilin 3 in receptor-mediated endocytosis.

Endophilin 1 (Endo1) participates in synaptic vesicle biogenesis through interactions of its Src homology 3 domain with the polyphosphoinositide phosphatase Synaptojanin and the GTPase Dynamin. Endo1 has also been reported to affect endocytosis by converting membrane curvature via its lysophosphatidic acid acyltransferase activity. Here we report that a closely related isoform of Endo1, Endo3, inhibits clathrin-mediated endocytosis. Mutational analyses showed that the variable region of Endo3 is important in regulating transferrin endocytosis. In the brain, Endo3 is co-localized with dopamine D2 receptor in olfactory nerve terminals and inhibits its clathrin-mediated endocytosis in COS-7 cells. Furthermore, overexpression of Endo3 in an olfactory epithelium-derived cell line suppressed dopamine D2 receptor-mediated endocytosis and therefore accelerated its dopamine-induced differentiation. These results indicate that Endo3 may act as a negative regulator of clathrin-mediated endocytosis in brain neurons.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Kallmann syndrome: fibroblast growth factor signaling insufficiency?

Kallmann syndrome (KAL) is a developmental disease that combines hypogonadotropic hypogonadism and anosmia. Anosmia is related to the absence or hypoplasia of the olfactory bulbs. Hypogonadism is due to GnRH deficiency and is likely to result from the failed embryonic migration of GnRH-synthesizing neurons. These cells normally migrate from the olfactory epithelium to the forebrain along the olfactory nerve pathway. KAL is phenotypically and genetically heterogeneous. The gene responsible for the X-chromosome linked form of the disease (KAL1) has been identified in 1991. KAL1 encodes anosmin-1, an approximately 95-kDa glycoprotein of unknown function which is present locally in various extracellular matrices during the period of organogenesis. The recent finding that FGFR1 mutations are involved in an autosomal dominant form of Kallmann syndrome (KAL2), combined with the analysis of mutant mouse embryos that no longer express Fgfr1 in the telencephalon, suggests that the disease results from a deficiency in FGF signaling at the earliest stage of olfactory bulb morphogenesis. We propose that the role of anosmin-1 is to enhance FGF signaling and suggest that the gender difference in anosmin-1 dose (because KAL1 partially escapes X-inactivation) explains the higher prevalence of the disease in males.

Extracellular Matrix Proteins↗
PubMed2000

Mesenchymal/epithelial induction mediates olfactory pathway formation.

In the olfactory pathway, as in the limbs, branchial arches, and heart, mesenchymal/epithelial induction, mediated by retinoic acid (RA), FGF8, sonic hedgehog (shh), and the BMPs, defines patterning, morphogenesis, and differentiation. Neuronal differentiation in the olfactory epithelium and directed growth of axons in the nascent olfactory nerve depend critically upon this inductive interaction. When RA, FGF8, shh, or BMP signaling is disrupted, distinct aspects of olfactory pathway patterning and differentiation are compromised. Thus, a cellular and molecular mechanism that facilitates musculoskeletal and vascular development elsewhere in the embryo has been adapted to guide the differentiation of the olfactory pathway in the developing forebrain.

Animals↗
PubMed2002

Novel microglomerular structures in the olfactory bulb of mice.

The murine olfactory system consists of two primary divisions: (1) a main olfactory system, in which olfactory sensory neurons (OSNs) located in the main olfactory epithelium (MOE) send their axons to glomeruli in the main olfactory bulb (MOB); and (2) an accessory olfactory system, in which OSNs located in the vomeronasal organ send their axons to glomeruli in the accessory olfactory bulb (AOB). In labeling studies using the lectin Ulex europaeus agglutinin (UEA), we discovered a novel subset of small neuropilar structures in the MOB that are distinct from other glomeruli both in the MOB and AOB. These "microglomeruli" are morphologically similar to MOB glomeruli in many respects: they receive innervation from processes present in the olfactory nerve layer and are isolated from other glomeruli by juxtaglomerular cells; in addition, the compartmental pattern of UEA labeling suggests the presence of UEA (-) processes within their neuropil. Microglomeruli contained processes that express the olfactory marker protein, a marker common to mature OSN axons. However, unlike other glomerular structures, the microglomeruli did not contain neural cell adhesion molecule-labeled processes. Within microglomeruli, UEA(+) processes interdigitated with MAP2(+) dendrites, some of which likely originate from interneurons, as indicated by glutamic acid decarboxylase labeling. Synaptophysin labeling in microglomeruli strongly suggested that synapses occur between UEA(+) processes and dendrites. Anterograde labeling of OSNs, by injection of rhodamine-dextran into one naris, demonstrated that UEA(+) processes in microglomeruli originated in the MOE. The unique morphology, protein expression, and location of microglomeruli have led us to hypothesize that they represent a novel class of glomerular structures in the murine olfactory system.

Animals↗