| Abstract No.: | B-A2021 |
| Country: | Canada |
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| Title: | EXTRACELLULAR MATRIX GLYCOPROTEIN TENASCIN-R AFFECTS ADULT BUT NOT DEVELOPMENTAL NEUROGENESIS IN THE OLFACTORY BULB |
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| Authors/Affiliations: | 1 Linda David*;
1 University Laval, Quebec, QC, Canada
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| Content: | The olfactory bulb (OB) is one of the two remarkable regions of the brain that sees the birth and integration of new neurons throughout the life-span of animals. Intensive investigations have identified countless mechanisms, molecules and cell types that play a part in this phenomenon. Despite this, we still know very little about the molecular cues that specifically affect the arrival and integration of new neurons in adult animals when compared to developing OB. Here we show that the extra cellular matrix glycoprotein Tenascin-R (TNR) orchestrates the arrival and integration of new neurons specifically in the adult OB. TNR is produced in the granule cell layer of the OB and its expression increases in an age-dependent manner. TNR deficiency results in the accumulation of newly born neurons in the core of the OB due to the defects in the radial migration of these neurons towards different OB layers. To understand the functional consequences of TNR deficiency, and therefore the reduced number of newborn neurons in the adult OB, we performed electrophysiological recordings in acute slices prepared from wild-type and TNR deficient animals. Recordings on spontaneous activity, spontaneous inhibitory postsynaptic currents (sIPSC) and miniature currents (mIPSC) from mitral cells, the target cells of newly generated interneurons, revealed a drastic reduction in the frequency of mIPSCs in the adult, 3-4 months old, TNR deficient animals. By contrast, electrophysiological recordings from mitral cells in 1 month old animals did not reveal any differences in the frequency, amplitude and kinetic of mIPSCs. These data suggest that TNR might specifically alter adult, but not early developmental neurogenesis in the OB, and, therefore, may provide a model to discern the implications of developmental and adult neurogenesis in the OB functioning. |
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