A circadian clock in the olfactory bulb controls olfactory responsivity
A circadian clock in the olfactory bulb controls olfactory responsivity
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DOI：
10.1523/jneurosci.3445-06.2006
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发表时间：
2006-11-22
影响因子：
5.3
通讯作者：
Herzog, Erik D.
中科院分区：
文献类型：
--
作者：
Granados-Fuentes, Daniel;Tseng, Alan;Herzog, Erik D.
最近，已经表明多种哺乳动物细胞类型在体外表达每日节律。虽然下丘脑的视交叉上核（SCN）是已知的调节范围广泛的昼夜节律行为，在其他组织的内在节律性的作用是未知的。我们测试了小鼠的主要嗅球（OB）是否介导嗅觉的日常变化。我们发现，在雪松油诱导的c-Fos，细胞兴奋的蛋白质标记，在二尖瓣和颗粒层的OB和梨状皮质（PC）的昼夜节律。这些振荡在恒定的黑暗中持续存在，振幅变化四倍，峰值类似于日常运动活动开始后4小时。SCN的电解质损伤废除昼夜运动节律，但在OB或PC的气味诱导的c-Fos节律。此外，去除OB取消了PC中c-Fos的自发昼夜节律循环，缩短了运动节律的自由运行期，并在光照时间表中提前6 h后加速了再夹带，延迟6 h后减慢了再夹带。OB消融或气味剂改变了SCN的c-Fos节律的振幅，消融一个OB可消除同侧PC的c-Fos节律，但对侧OB和PC无此作用。我们的结论是，OB包括一个主昼夜节律起搏器，它增强嗅觉反应，每晚，驱动节奏的PC，并与SCN相互作用，以协调其他日常行为。
Recently, it has been shown that multiple mammalian cell types express daily rhythms in vitro. Although the suprachiasmatic nucleus (SCN) of the hypothalamus is known to regulate a wide range of circadian behaviors, the role for intrinsic rhythmicity in other tissues is unknown. We tested whether the main olfactory bulb (OB) of mice mediates daily changes in olfaction. We found circadian rhythms in cedar oil-induced c-Fos, a protein marker of cellular excitation, in the mitral and granular layers of the OB and in the piriform cortex (PC). These oscillations persisted in constant darkness with a fourfold change in amplitude and a peak similar to 4 h after the onset of daily locomotor activity. Electrolytic lesions of the SCN abolished circadian locomotor rhythms, but not odor-induced c-Fos rhythms in the OB or PC. Furthermore, removal of the OB abolished spontaneous circadian cycling of c-Fos in the PC, shortened the free-running period of locomotor rhythms, and accelerated re-entrainment after a 6 h advance and slowed re-entrainment after a 6 h delay in the light schedule. OB ablation or odorant altered the amplitude of c-Fos rhythms in the SCN and ablation of one OB abolished c-Fos rhythms in the ipsilateral PC, but not in the contralateral OB and PC. We conclude that the OB comprises a master circadian pacemaker, which enhances olfactory responsivity each night, drives rhythms in the PC, and interacts with the SCN to coordinate other daily behaviors.