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What the nose knows : diversity of mice olfactory sensory neurons as odor detectors and mechanical sensors| old_uid | 2803 |
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| title | What the nose knows : diversity of mice olfactory sensory neurons as odor detectors and mechanical sensors |
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| start_date | 2007/05/11 |
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| schedule | 09h |
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| online | no |
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| location_info | salle 3302 |
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| details | Invitation : Brigitte Paulignan |
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| summary | To understand how odor information is encoded and processed from the nose to the bulb, it is crucial to know how similar or dissimilar the odorant response properties are of olfactory sensory neurons (OSN) that express the same odorant receptor and thus project their axons to the same glomeruli. The intrinsic complexity of the olfactory epithelium, i.e., millions of OSNs expressing >1000 odorant receptors and responding to thousands of odorants, has hindered the functional study on the OSNs. We developed two strategies to control the number of receptors present in the OSNs we record in mice. First we analyzed the response properties of OSNs located in the septal organ of Masera, a small island of olfactory epithelium located in the ventral part of the nasal cavity and expressing a limited set of receptors. Using perforated patch-clamp recording, we found out that 75% of these OSNs respond to multiple odorants structurally different, with a high sensitivity and a broad dynamic range, indicating that the septal organ might be an odorant detector. These OSNs also responded to a mechanical stimulus applied using a puffing electrode. This property may contribute to send the breathing and sniffing information to the bulb. Our second strategy was to analyze the response properties of OSNs expressing specific receptors in gene-targeted mice. In these lines of mice, GFP is expressed in OSNs expressing the receptors MOR23, M71 or S1. Using perforated patch-clamp recordings we found out that the responses’ kinetics of MOR23 OSNs to their major ligand (lyral) varied from cell to cell. Their dynamic range was broad, covering more than 3 log units. Similar recordings of M71 and S1 cells showed that the dynamic range depends on the couple ligand-receptor. We hypothesize that variations among cells expressing the same receptors are due to variations in maturation stages of the OSNs. |
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| responsibles | Grimault |
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