Search results for "OLFACTORY EPITHELIUM"

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…

2019

The olfactory epithelium is continuously exposed to exogenous chemicals, including odorants. During the past decade, the enzymes surrounding the olfactory receptors have been shown to make an important contribution to the process of olfaction. Mammalian xenobiotic metabolizing enzymes, such as cytochrome P450, esterases and glutathione transferases (GSTs), have been shown to participate in odorant clearance from the olfactory receptor environment, consequently contributing to the maintenance of sensitivity toward odorants. GSTs have previously been shown to be involved in numerous physiological processes, including detoxification, steroid hormone biosynthesis, and amino acid catabolism. The…

Odorant metabolizing enzymes in the peripheral olfactory process

2016

Odorant metabolizing enzymes in the peripheral olfactory process

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…

Impact of the Usher syndrome on olfaction

2015

Usher syndrome is a genetically and clinically heterogeneous disease in humans, characterized by sensorineural hearing loss, retinitis pigmentosa and vestibular dysfunction. This disease is caused by mutations in genes encoding proteins that form complex networks in different cellular compartments. Currently, it remains unclear whether the Usher proteins also form networks within the olfactory epithelium (OE). Here, we describe Usher gene expression at the mRNA and protein level in the OE of mice and showed interactions between these proteins and olfactory signaling proteins. Additionally, we analyzed the odor sensitivity of different Usher syndrome mouse models using electro-olfactogram re…

Odour perception: A review of an intricate signalling pathway

2015

The perception of odours is the result of the complex processing of a signal, which initiates at peripheral receptors and ends in the brain. Along this pathway, olfactory signal processing proceeds through several steps; each step possesses its own complexity, and all steps are also intricately connected. This review aims to describe the main intricate steps of olfactory processing in mammals, some of which remain unclear, and the close associations and overlapping nature of these steps. The causes of both the complexity and the variability of olfactory signals are examined: the nature of olfactory receptors, involving the diversity of the genome; the spatial organization of the olfactory e…

Olfactory system in mammals: structural and functional anatomy

2016

Olfactory system in mammals: structural and functional anatomy

A binary genetic approach to characterize TRPM5 cells in mice

2015

International audience; Transient receptor potential channel subfamily M member 5 (TRPM5) is an important downstream signaling component in a subset of taste receptor cells making it a potential target for taste modulation. Interestingly, TRPM5 has been detected in extra-oral tissues; however, the function of extra-gustatory TRPM5-expressing cells is less well understood. To facilitate visualization and manipulation of TRPM5-expressing cells in mice, we generated a Cre knock-in TRPM5 allele by homologous recombination. We then used the novel TRPM5-IRES-Cre mouse strain to report TRPM5 expression by activating a tau GFP transgene. To confirm faithful coexpression of tau GFP and TRPM5 we gene…

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,…

Odorant Metabolism Analysis by an Automated Ex Vivo Headspace Gas-Chromatography Method

2015

International audience; In the olfactory epithelium (OE), odorant metabolizing enzymes have the dual function of volatile component detoxification and active clearance of odorants from the perireceptor environment to respectively maintain the integrity of the tissues and the sensitivity of the detection. Although emphasized by recent studies, this enzymatic mechanism is poorly documented in mammals. Thus, olfactory metabolism has been characterized mainly in vitro and for a limited number of odorants. The automated ex vivo headspace gas-chromatography method that was developed here was validated to account for odorant olfactory metabolism. This method easily permits the measurement of the f…