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At least 19 recordsLinked to original sources
PubMed2006

Ultrastructural localization of connexins (Cx36, Cx43, Cx45), glutamate receptors and aquaporin-4 in rodent olfactory mucosa, olfactory nerve and olfactory bulb.

Odorant/receptor binding and initial olfactory information processing occurs in olfactory receptor neurons (ORNs) within the olfactory epithelium. Subsequent information coding involves high-frequency spike synchronization of paired mitral/tufted cell dendrites within olfactory bulb (OB) glomeruli via positive feedback between glutamate receptors and closely-associated gap junctions. With mRNA for connexins Cx36, Cx43 and Cx45 detected within ORN somata and Cx36 and Cx43 proteins reported in ORN somata and axons, abundant gap junctions were proposed to couple ORNs. We used freeze-fracture replica immunogold labeling (FRIL) and confocal immunofluorescence microscopy to examine Cx36, Cx43 and Cx45 protein in gap junctions in olfactory mucosa, olfactory nerve and OB in adult rats and mice and early postnatal rats. In olfactory mucosa, Cx43 was detected in gap junctions between virtually all intrinsic cell types except ORNs and basal cells; whereas Cx45 was restricted to gap junctions in sustentacular cells. ORN axons contained neither gap junctions nor any of the three connexins. In OB, Cx43 was detected in homologous gap junctions between almost all cell types except neurons and oligodendrocytes. Cx36 and, less abundantly, Cx45 were present in neuronal gap junctions, primarily at "mixed" glutamatergic/electrical synapses between presumptive mitral/tufted cell dendrites. Genomic analysis revealed multiple miRNA (micro interfering RNA) binding sequences in 3'-untranslated regions of Cx36, Cx43 and Cx45 genes, consistent with cell-type-specific post-transcriptional regulation of connexin synthesis. Our data confirm absence of gap junctions between ORNs, and support Cx36- and Cx45-containing gap junctions at glutamatergic mixed synapses between mitral/tufted cells as contributing to higher-order information coding within OB glomeruli.

Animals↗
PubMed1957

Electron microscopic observations of the olfactory mucosa and olfactory nerve.

The olfactory receptor cell is characterized by a distal process (the dendrite) which terminates in the olfactory passage as the olfactory rod. The olfactory rod is provided with numerous cilia which are similar in structure to those seen in other tissues. The central processes of the bipolar cell constitute the fila olfactoria. The cytoplasmic organelles of the sustentacular cell are concentrated at the apical and basal ends of the cell with a paucity of cytoplasmic elements in the region of the nucleus. The plasma membrane of the supporting cell forms a mesaxon for both the dendrite and axon of the bipolar cell. Terminal bars are present in the epithelial cells. The axons constituting the fila olfactoria form fascicles which are ensheathed by mesaxons of adjacent Schwann cells. Thus the olfactory neurons are ensheathed throughout their course by the membranes of sustentacular and Schwann cells. Observations of the olfactory mucosa with the electron microscope are discussed with respect to recent electrophysiological studies.

Axons↗
PubMed1981

[Somatotopic relations between the olfactory mucosa and the olfactory bulb in the triton].

The axons of receptors located in the olfactory neuroepithelium are known to synapse with mitral cell dendrites in the glomerular layer of the ipsilateral olfactory bulb, but few previous studies showed a clear-cut topological organization of this projection. We therefore injected horseradish peroxidase (HRP) into restricted areas of the olfactory mucosa in adult tritons, Triturus cristatus. The animals were perfused with glutaraldehyde 17 h later; the mucosa, the olfactory nerve and bulb were removed, serially cut and treated with diaminobenzidine to reveal the localization and extent of the injection and the areas in the glomerular layer of the bulb to which the injected HRP had been transported by anterograde axonal flow. Small injections of HRP tended to label a small area in the bulb, while larger injections projected to a wider zone. The results also indicated the existence of an orderly projection, with a transposition of the dorso-ventral axis of the neuroreceptor sheet into an essentially anteroposteriorly oriented axis in the bulb. Thus, the dorsally located areas of the olfactory mucosa project to the most anterior part of the glomerular layer, whereas the vomero-nasal mucosa, which is located near the most lateral part of the ventral mucosa, projections to the posterior enlargement of the glomerular layer in the bulb. The data also showed that nerve bundles within the olfactory nerve maintain are orderly position which depends upon their origin. It is postulated that this somatopic organization reflects the development undergone by the peripheral olfactory system during ontogenesis.

Animals↗
PubMed1990

Immunohistochemical examination of olfactory mucosa in patients with olfactory disturbance.

The olfactory mucosa was examined by immunohistochemistry in patients with olfactory disturbance: anosmia due to choanal atresia and chronic sinusitis, early-stage common cold, late-stage common cold, and head trauma. The results indicate that the olfactory mucosa of patients with olfactory disturbance shows specific kinds of immunoreactive patterns and that immunohistochemistry is useful for examining the degree of degeneration of pathologic human olfactory mucosa and for clarification of prognosis.

Choanal Atresia↗
PubMed1983

Influence of a detergent on the catfish olfactory mucosa.

The olfactory mucosa of the catfish (Ictulurus punctatus) has been briefly exposed to various concentrations of the non-ionic detergent Triton X-100. At high concentrations (1-4%) the upper layer of cells constituting the sensory and non-sensory areas of the lamellae is extensively damaged and new receptor cells do not appear in significant number before 2 months after treatment. Respiratory cells regenerate first followed by sustentacular and olfactory receptors. The regenerative process is very similar to that described previously after prolonged contact between the mucosa and ZnSO4. Low detergent concentrations 0.03-0.1% affect only the sensory area. Olfactory and sustentacular microvilli and cilia, are immediately severed by the chemical. Regeneration occurs within the next 4 days. The cellular membranes appear also to be affected. From anatomical, electrophysiological and biochemical studies both in vivo and in vitro, it can be hypothesized that a receptors involved in the transduction process are solubilized by the detergent but reappear at a level corresponding to 50-60% of their original activity within 2 h. Proteins, having an amino acid binding effectiveness correlated to the amino acid electrophysiological activities measured in vivo, can be isolated from the solubilized material. Further studies will be necessary to confirm that some of these molecules are involved in the olfactory transduction mechanism.

Amino Acids↗
PubMed1994

Olfactory mucosa of patients with olfactory disturbance following head trauma.

The olfactory mucosa in 7 patients with olfactory disturbance following head trauma were sampled for biopsy with special biopsy forceps and examined by immunohistochemical staining with anti-neuron-specific enolase (NSE) and S-100 protein (S-100) antibodies. The residual olfactory receptor cells and nerve bundles were counted, and the degree of degeneration was determined. In 5 patients, olfactory receptor cells that reacted with anti-NSE antiserum remained, although the number varied with the patient, and in 2 patients the receptor cells disappeared. In the lamina propria, the S-100-immunoreactive olfactory nerves were retained in 6 patients. The outcome was poor in all cases regardless of the number of residual receptor cells and nerve bundles. These results indicate that the degree of impairment of the peripheral olfactory region after head trauma differs from case to case, and that even if the receptor cells and nerve bundles remain, it is difficult to improve the condition, although some cases of malingering may be contained.

Adolescent↗
PubMed2004

Zonal expression and activity of glutathione S-transferase enzymes in the mouse olfactory mucosa.

The rodent olfactory mucosa is characterized by a mosaic of gene expression that is exhibited among various cell types. Olfactory sensitivity in these animals is conveyed through odorant receptor families that are distinctly expressed within various subsets of the olfactory neuron population. Receptor neurons that express a particular class of odorant receptors exhibit bilaterally symmetric zones, which generally define their location within the nasal cavity. Less characterized are zonal expression profiles of proteins among non-neuronal cell types of the olfactory mucosa. In this study, we survey the expression of three glutathione S-transferase (GST) isozymes (alpha, mu, and pi) in the mouse olfactory mucosa and characterize the zonal expression of the mu isozyme. Immunohistochemistry and Western blot analysis of the GST mu isozyme reveal that the lateral olfactory turbinates I, Ib, II, IIb, and III display a greater intensity of expression for GST mu, in comparison to the dorsal and septal regions of the mucosa. GST alpha and pi isozymes do not display any distinct zonal organization in olfactory tissue of the adult mouse. When the general substrate 1-chloro-2-4-dinitrobenzene (CDNB) was used to assess GST activity within the olfactory tissue, the lateral turbinate regions displayed a higher level of activity when compared to dorsal or septal regions. Analysis of GST mu expression in prenatal and early postnatal olfactory tissue also reveals a zonal expression of the isozyme. We relate the significance of these findings to metabolic topography and olfactory chemosensory function.

Animals↗
PubMed1988

Examination and classification of human olfactory mucosa in patients with clinical olfactory disturbances.

To determine objectively the degree of olfactory disturbance, we biopsied the olfactory mucosa from patients who complained of anosmia. The olfactory disturbances in this study were caused by choanal atresia, chronic sinusitis, viral inflammation, and head trauma, as well as by congenital and idiopathic anosmia. The biopsy specimens were examined by light microscopy and the degree of mucosal degeneration present was classified according to five grades. The clinical courses of the patients studied paralleled the changes found in the olfactory mucosa.

Adolescent↗
PubMed1990

Immunopathology of olfactory mucosa following injury to the olfactory bulb.

Removal of the olfactory bulb was performed on rats in an attempt to elucidate the processes of olfactory dysfunction following head injury. Degeneration and regeneration of the olfactory mucosa were examined, histopathologically and immunohistochemically. We used antisera to olfactory marker protein (OMP) and neuron specific enolase (NSE) as a marker of the mature olfactory receptor neurons. Following rapid degeneration after bulbectomy, the olfactory receptor neurons regenerated. OMP and NSE containing cells re-appeared 49 days later. However, the cell population of the neuroepithelium did not revert to the numbers observed in the non-operated neuroepithelium, even three months later. The lack of a connection between regenerated axons and the olfactory bulb may result in immature neuronal replacement and reduce the number of olfactory receptor neurons.

Animals↗
PubMed2004

Pathology of the olfactory mucosa: implications for the treatment of olfactory dysfunction.

OBJECTIVE: The pathology of the olfactory mucosa is poorly understood; however, most cases of hyposmia and anosmia appear to be associated with a decline in the number of functioning mature olfactory sensory neurons (OSNs). Under normal conditions, OSNs undergo apoptotic cell death at a baseline rate likely secondary to their exposed location in the nose. Regeneration of mature OSNs from precursors in the epithelium allows the animal to maintain an adequate number of neurons necessary for olfactory sensation. In many cases of olfactory dysfunction, this balance is apparently disturbed, with a net loss of OSNs. The current study will examine normal and diseased olfactory tissue for the presence of data demonstrating that the preferred mechanism of OSN cell death is apoptotic in both health and disease. The potential therapeutic implications will be discussed. STUDY DESIGN: Histologic analysis of human and animal olfactory tissue. METHODS: Normal and diseased human and animal olfactory mucosa were assessed for immunohistochemical evidence of apoptosis. RESULTS: Increased activity of the apoptotic effector enzyme caspase-3 was demonstrated in diseased olfactory mucosa in comparison with normal controls. CONCLUSION: These results indicate that a common pathway may mediate OSN cell death from a diverse set of pathologic insults including aging, trauma, and sinusitis. Interference with this pathway of cell death is currently the subject of intense pharmacotherapeutic research for the management of stroke and meningitis. These drugs may ultimately prove useful in the treatment of clinical olfactory dysfunction.

Aging↗
PubMed1984

Histological and histochemical studies of the secretory components of the salamander olfactory mucosa: effects of isoproterenol and olfactory nerve section.

Secretory components of the salamander olfactory mucosa, sustentacular cells (SC), and Bowman's glands (BG), were examined histologically and histochemically. In the aquatic larval salamander, SC in sensory grooves contained secretory granules; the submucosa contained a single layer of homogeneous, ductless glands. In the land-dwelling adult salamander, SC spanning a flat epithelial sheet contained vesicles. Subjacent to the epithelium in both dorsal and ventral mucosae lay BG whose ducts opened at the surface of the epithelium. In the ventral mucosa, two additional layers of olfactory glands (OG) lying below the BG were identified; ducts were not observed in association with the OG. The beta-adrenergic agonist isoproterenol caused depletion of secretory granules from BG and OG of larval, young, and adult salamanders but had no discernible effect on SC. Histochemical techniques (Alcian blue at pH 2.5 and pH 1.0, high-iron diamine, and the periodic acid-Schiff reaction) demonstrated that SC contained neutral, acidic, and small amounts of sulfated mucopolysaccharides (MPS), BG and OG contained only neutral MPS. In contrast, glands under adjacent respiratory epithelium contained both acidic and sulfated MPS. Unilateral olfactory nerve section ( ONX ) caused changes in the histochemical reactivity of acidic and sulfated MPS in SC on the ipsilateral and later on the contralateral side. Neutral MPS staining became enhanced first in the OG that lay under the BG, then in BG cells, and later in the deepest OG layer. Ipsilateral changes preceded contralateral ones. At 24 days post- ONX , some acinar cells in the deep OG contained acidic but not sulfated MPS.

Animals↗
PubMedDate not supplied

[Electron microscopic analysis of the effect of modulated microwave radiation on isolated rat olfactory mucosa].

Isolated olfactory neuroepithelium and neighbouring respiratory epithelium of 6 Wistar rats after exposure to high frequency irradiation (the microwave carrier frequency was 0.9 GHz; the rectangular pulse modulation was 16 pulses per second; the pulse duration was 50%; the microwave power density in exposure glass chamber was 15 W/kg; the exposure time was 15 min) were studied using high resolution transmission electron microscopy. Ultrathin sections of both epithelia showed the drastic changes in ultrastructure of mucosa. Knobs of primary olfactory neurons and apical parts of supporting (sustacle) cells of the neuroepithelium showed strong vacuolization due to stimulating effect of the microwave irradiation on mucus secretion. The fusion of neighbouring cilia of respiratory cells was revealed. Such "giant cilia" contained more than 5-10 axonemes with basal bodies. In one case the mucus contained paracrystalline structures which were formed by microvilli and nonidentified filamentous protein (10 nm in dia). Degeneration of primary olfactory neuron axons was revealed.

Animals↗
PubMed1992

Cytochromes P450 NMa, NMb (2G1), and LM4 (1A2) are differentially expressed during development in rabbit olfactory mucosa and liver.

Mammalian olfactory mucosa has a high concentration of cytochrome P450 monooxygenases (P450). The major olfactory P450 isoforms in adult rabbits include P450 NMa, which is found in both olfactory and respiratory mucosa, as well as in liver at a low level, P450 NMb (2G1), which is olfactory specific, and P450 form 4 (1A2), which is found only in liver and olfactory mucosa. In the present study, we have found that the developmental expression of olfactory P450 in rabbits is not coordinated with the ontogenesis of hepatic P450. These three P450 isoforms were detected immunochemically and found to be at a relatively high level in olfactory but not hepatic microsomes in the first 2 weeks after birth. In the liver, NMb is not detectable at any age and NMa is not detectable until the fourth week. P450 1A2 is not detectable until the third week, but its level increases rapidly in the fourth week. These P450 isoforms are also detectable in prenatal olfactory tissue at 2 days before birth, indicating that direct exposure to air is not a prerequisite for their early expression in this tissue and that the early appearance of these enzymes may be controlled by both endogenous and environmental factors. In addition, the developmental expression of 2E1, a minor olfactory P450 isoform, also occurs earlier in olfactory mucosa than in liver, and the same conclusion can be made about the expression of NADPH-P450 reductase, which is detectable in olfactory microsomes but not in hepatic microsomes from prenatal rabbits. Thus, the regulatory mechanisms that control basal prenatal expression in the olfactory tissue may be common for multiple P450 isoforms and perhaps also for other biotransformation enzymes. The tissue-specific early onset of expression of multiple forms of P450 in olfactory tissue suggests that these enzymes may play an important role in the neonatal period, when olfactory ability is vital for the survival of the newborn. The presence of relatively high levels of biotransformation enzymes in the olfactory mucosa may also have important implications for neonatal inhalation toxicology.

Animals↗
PubMed1991

Immunohistopathology of variations of human olfactory mucosa.

The characteristics of the human olfactory mucosa were studied immunohistologically. Regular, zonal distribution of the supporting cells, multilayered olfactory receptor cells and basal cells was commonly found in the olfactory mucosa of the human fetus. In contrast, most of the olfactory mucosa in the adult varied to some extent. In the relatively thick, slightly degenerated olfactory mucosa, olfactory marker protein positive receptor cells were arranged irregularly. The most common evidence for variation was the decrease or disappearance of the olfactory receptor cells. Serous-type lactorferrin-containing glandular acini were characteristically found beneath degenerated epithelium. Islands of respiratory epithelium were also seen. The ductules of the Bowman's glands were distended and the openings of these ductules were wide. There was invagination or epithelial cell processes into the glandular lumina. These findings suggest that the epithelial cells of Bowman's glands play an important role in the regeneration of the human olfactory mucosa.

Adult↗
PubMed2005

The mitosis and immunocytochemistry of olfactory ensheathing cells from nasal olfactory mucosa.

OBJECTIVE: To culture olfactory ensheathing cells (OECs) of rats in vitro and to investigate its morphology, mitosis and immunocytochemistry, and to explore if the OECs could be a new donation for transplantation. METHODS: OECs were harvested from olfactory mucosa of Sprague Dawley rats based on the differing rates of attachment of the various cell types, followed by glial fibrillary acidic protein (GFAP), nerve growth factor (NGF), anti-low affinity receptor for NGF (NGFRp75), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and S-100 immunocytochemistry. The morphological changes and mitosis were observed under a phase contrast microscope at different culture time. RESULTS: Three morphologically distinct types of cells, bipolar, multipolar and flat morphology were present in the primary culture of adult rat olfactory mucosa. Mitosis was characterized by a retraction of all processes, forming a sphere that divided into spherical daughter cells, the daughter cells sent out their processes. The OECs were immunoreactive for GFAP, NGFRp75, S-100, NGF, BDNF and NT-3. CONCLUSIONS: The OECs from nasal olfactory mucosa cultivated in the medium with fetal bovine serum could survive, divide, differentiate, and express the neurotrophin. It may become an accessible source for autologous grafting in spinal cord injury.

Animals↗
PubMed1999

Methimazole toxicity in rodents: covalent binding in the olfactory mucosa and detection of glial fibrillary acidic protein in the olfactory bulb.

Methimazole is an antithyroid drug reported to affect the sense of smell and taste in humans. The aim of the present study was to examine the distribution and effects of methimazole on the olfactory system in rodents. Autoradiography showed a selective covalent binding of 3H-labeled methimazole in the Bowman's glands in the olfactory mucosa, bronchial epithelium in the lungs, and centrilobular parts of the liver following an iv injection in mice. Histopathology showed an extensive lesion in the olfactory mucosa that was efficiently repaired 3 months after two consecutive ip doses of methimazole. The effect of methimazole on various brain regions was studied by determining levels and location of glial fibrillary acidic protein (GFAP). The results showed a threefold increase of GFAP in the olfactory bulb 2 weeks after treatment with methimazole whereas no change was observed 4 days after treatment. Pretreatment of mice with thyroxine did not protect against the methimazole-induced toxicity in the olfactory mucosa and bulb. In contrast, pretreatment with the cytochrome P450 inhibitor metyrapone completely prevented the covalent binding and toxicity of methimazole in the olfactory mucosa and bulb. The present results suggest that the methimazole-induced toxicity in the olfactory mucosa is mediated by a cytochrome P450-dependent metabolic activation of the compound into reactive metabolites that are bound to various tissues including the olfactory mucosa. The increase of GFAP in the olfactory bulb of methimazole-treated mice is suggested to be a secondary phenomenon due to the primary damage in the olfactory mucosa.

Animals↗