Search results for " epithelium"
showing 10 items of 249 documents
Activity and expression of drug metabolizing enzymes in olfactory mucosa of rats treated by hepatic inducers
2008
International audience; Several drug-metabolizing enzymes (DME), such as cytochrome P450- dependent monooxygenases (CYP) and transferases have been characterized in the olfactory epithelium. Some of them are preferentially expressed in this tissue, while others are similar to those present in the liver. The role of these enzymes remains unclear. Since the olfactory mucosa is in direct contact with the external environment, these enzymes can contribute to the detoxification of chemical compounds. In addition, these enzymes could be involved in the olfaction process, especially in the biotransformation of odorants. Indeed, the rapid inactivation and clearance of odorants is a prerequisite for…
Ontogenesis of the Extra-Bulbar Olfactory Pathway inXenopus laevis
2013
Although the development, anatomy, and physiology of the vertebrate olfactory system are fairly well understood, there is still no clear definition of the terminal nerve complex acknowledged by all. Among the most debated matters is whether or not the extrabulbar projections found in anamniotes should or should not be considered part of the terminal nerve complex. In this context, we investigated the early development of the extrabulbar pathway in Xenopus larvae from placodal differentiation to postmetamorphic stages. We showed that the extrabulbar fibers become visible around Stage 42 and are conserved throughout metamorphosis. We confirmed previous reports concerning their central project…
Acute effects of 1,1,1-trichloroethane on human olfactory functioning.
2004
Background Animal experiments indicate that 1,1,1-trichloroethane can cause degeneration of the olfactory epithelium. The effects of 1,1,1-trichloroethane on human odor perception still have not been investigated. The goal of this study was to learn more about acute effects of 1,1,1-trichloroethane. Methods Twelve healthy, nonsmoking students were exposed to 200 and 20 ppm (control) 1,1,1-trichloroethane in an exposure chamber for 4 hours according to a crossover design. Olfactory functioning was investigated with the Sniffin’ Sticks. The test includes the determination of the detection threshold for n-butanol and an odor identification test. Results After 1 hour of exposure to 200 ppm 1,1,…
UDP-glucuronosyltransferases (UGTs) in neuro-olfactory tissues: expression, regulation, and function.
2010
International audience; This work aims to review uridine diphosphate (UDP)-glucuronosyltransferase (UGT) expression and activities along different neuronal structures involved in the common physiological process of olfaction: olfactory epithelium, olfactory bulb, and olfactory cortex. For the first time, using high-throughput in situ hybridization data generated by the Allen Brain Atlas (ABA), we present quantitative analysis of spatial distribution of UGT genes in the mouse brain. The olfactory area is a central nervous system site with the highest expression of UGTs, including UGT isoforms not previously identified in the brain. Since there is evidence of the transfer of xenobiotics to th…
Rat olfactory bulb and epithelium UDP-glucuronosyltransferase 2A1 (UGT2A1) expression: in situ mRNA localization and quantitative analysis.
2001
UDP-glucuronosyltransferases (UGTs) form a multigenic family of enzymes involved in the biotransformation and elimination of numerous endo- and xenobiotic compounds. Beside the diverse UGT isoforms present in the liver as well as in other tissues, the UGT2A1 isoform, also called olfactory UGT, was initially thought to be expressed in the nasal epithelium only. In this work, we demonstrate the UGT2A1 mRNA expression in the olfactory bulb, using in situ hybridization and quantitative reverse transcription-polymerase chain reaction (RT-PCR) techniques. Within the epithelium, UGT2A1 mRNA is mainly found in the sustentacular cells and to a lesser extent in Bowman's gland cells. Moreover, in situ…
Use of ultrasonic vocalizations to assess olfactory detection in mouse pups treated with 3-methylindole.
2005
International audience; Altricial mammals use olfaction long before the olfactory bulb has reached its anatomically mature state. Indeed, while audition and vision are still not functional, the olfactory system of newborn animals can clearly process distinct odorant molecules. Although several previous studies have emphasized the important role that olfaction plays in early critical functions, it has been difficult to develop a sensitive and reliable test to precisely quantify olfactory ability in pups. One difficulty in determining early sensory capabilities is the rather limited behavioral repertory of neonates. The present study examines the use of ultrasonic vocalizations emitted by iso…
Synaptogenesis in the mouse olfactory bulb during glomerulus development
2008
Synaptogenesis is essential for the development of neuronal networks in the brain. In the olfactory bulb (OB) glomeruli, numerous synapses must form between sensory olfactory neurons and the dendrites of mitral/tufted and periglomerular cells. Glomeruli develop from E13 to E16 in the mouse, coincident with an increment of the neuropil in the border between the external plexiform (EPL) and olfactory nerve layers (ONL), coupled to an extensive labelling of phalloidin and GAP-43 from the ONL to EPL. We have tracked synaptogenesis in the OB during this period by electron microscopy (EM) and immunolabelling of the transmembrane synaptic vesicle glycoprotein SV-2. No SV-2 labelling or synapses we…
Types of cholecystokinin-containing periglomerular cells in the mouse olfactory bulb
2010
The periglomerular cells (PG) of the olfactory bulb (OB) are involved in the primary processing and the refinement of sensory information from the olfactory epithelium. The neurochemical composition of these neurons has been studied in depth in many species, and over the last decades such studies have focused mainly on the rat. The increasing use of genetic models for research into olfactory function demands a profound characterization of the mouse olfactory bulb, including the chemical composition of bulbar interneurons. Regarding both their connectivity with the olfactory nerve and their neurochemical fate, recently, two different types of PG have been identfied in the mouse. In the prese…
Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identifie…
2015
Analyzing the physiological responses of olfactory sensory neurons (OSN) when stimulated with specific ligands is critical to understand the basis of olfactory-driven behaviors and their modulation. These coding properties depend heavily on the initial interaction between odor molecules and the olfactory receptor (OR) expressed in the OSNs. The identity, specificity and ligand spectrum of the expressed OR are critical. The probability to find the ligand of the OR expressed in an OSN chosen randomly within the epithelium is very low. To address this challenge, this protocol uses genetically tagged mice expressing the fluorescent protein GFP under the control of the promoter of defined ORs. O…
Postnatal odorant exposure induces peripheral olfactory plasticity at the cellular level
2014
Mammalian olfactory sensory neurons (OSNs) form the primary elements of the olfactory system. Inserted in the olfactory mucosa lining of the nasal cavity, they are exposed to the environment and their lifespan is brief. Several reports say that OSNs are regularly regenerated during the entire life and that odorant environment affects the olfactory epithelium. However, little is known about the impact of the odorant environment on OSNs at the cellular level and more precisely in the context of early postnatal olfactory exposure. Here we exposed MOR23-green fluorescent protein (GFP) and M71-GFP mice to lyral or acetophenone, ligands for MOR23 or M71, respectively. Daily postnatal exposure to …