Temporal precision in the mammalian circadian system: A reliable clock from less reliable neurons
Temporal precision in the mammalian circadian system: A reliable clock from less reliable neurons
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DOI：
10.1177/0748730403260776
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发表时间：
2004-02-01
影响因子：
3.5
通讯作者：
Tei, H
中科院分区：
文献类型：
--
作者：
Herzog, ED;Aton, SJ;Tei, H
哺乳动物的SCN包含一个生物钟，在体内和体外都能驱动非常精确的昼夜节律。这项研究询问小鼠行为节律的周期间变异性是否可以归因于SCN内单个昼夜节律起搏器的精确度或它们之间的相互作用。作者测量了周期周期与7天转轮活动记录的标准差，培养的SCN外植体中Perod1基因的表达，以及分散的SCN神经元的放电率模式。完整组织和动物的周期变异性低于单个神经元。分散的SCN神经元的跑轮节律和周期1节律的中位数变异小于40min/周期，而放电频率节律的中位数变异为2.1h。最精确的SCN神经元的周期偏差为1.1h，是最精确的SCN外植体(0.1h)和小鼠(0.1h)的10倍，但与最不稳定的外植体(2.1h)和小鼠(1.1h)相当。这种变异性与小鼠和SCN外植体的内在周期有关，但与单细胞无关。精确度与节律的幅度无关，在出生后一年内不随年龄而显著变化。对周期间周期的序列相关性分析表明，这种变异性的大约一半可归因于起搏器外的噪声。这些结果表明，SCN内的细胞-细胞相互作用减少了起搏器噪声，以确定组织和行为中昼夜节律的精确度。
The mammalian SCN contains a biological clock that drives remarkably precise circadian rhythms in vivo and in vitro. This study asks whether the cycle-to-cycle variability of behavioral rhythms in mice can be attributed to precision of individual circadian pacemakers within the SCN or their interactions. The authors measured the standard deviation of the cycle-to-cycle period from 7-day recordings of running wheel activity, Period1 gene expression in cultured SCN explants, and firing rate patterns of dispersed SCN neurons. Period variability of the intact tissue and animal was lower than single neurons. The median variability of running wheel and Period1 rhythms was less than 40 min per cycle compared to 2.1 h in firing rate rhythms of dispersed SCN neurons. The most precise SCN neuron, with a period deviation of 1.1 h, was 10 times noisier than the most accurate SCN explant (0.1 h) or mouse (0.1 h) but comparable to the least stable explant (2.1 h) and mouse (1.1 h). This variability correlated with intrinsic period in mice and SCN explants but not with single cells. Precision was unrelated to the amplitude of rhythms and did not change significantly with age up to I year after birth. Analysis of the serial correlation of cycle-to-cycle period revealed that approximately half of this variability is attributable to noise outside the pacemaker. These results indicate that cell-cell interactions within the SCN reduce pacemaker noise to determine the precision of circadian rhythms in the tissue and in behavior.