期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：26
页码：9822-9826
DOI：10.1073/pnas.0403361101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Cholinergic axons and nicotinic receptors are abundant in all layers of the olfactory bulb (OB), the main region of newborn neuron integration in the adult brain. Here, we report that the OB granule cell layer in mice lacking the predominant form of brain high-affinity nicotinic acetylcholine receptors ({beta}2-/- mice) displayed nearly 50% more newborn neurons and significantly fewer apoptotic cells than did {beta}2+/+ mice. Conversely, in vivo chronic nicotine exposure significantly decreased the number of newborn granule cells in {beta}2+/+ but not {beta}2-/- adult mice, confirming that the survival of newborn neurons can be controlled by the activation of {beta}2-containing nicotinic acetylcholine receptors. Unexpectedly, investigating the behavioral consequence of an increased number of granule cells in {beta}2-/- mice revealed that these animals have a less robust short-term olfactory memory than their wild-type counterparts. Taken together, these results provide evidence that high-affinity nicotinic receptors are involved in the maturation of adult OB local circuits. They also indicate that an increase in the number of granule cells does not necessarily correlate with better olfactory performance and further highlight the importance of cholinergic afferents for olfactory processing.
