A Wake-Promoting Circadian Output Circuit in Drosophila
A Wake-Promoting Circadian Output Circuit in Drosophila
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DOI：
10.1016/j.cub.2018.07.024
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发表时间：
2018-10-08
期刊：
影响因子：
9.2
通讯作者：
Jepson, James E. C.
中科院分区：
文献类型：
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作者：
Lamaze, Angelique;Kratschmer, Patrick;Jepson, James E. C.
昼夜节律钟在整个昼夜周期中门控睡眠和觉醒状态中发挥保守作用[1-5]。据报道，在果蝇Drosophila melanogaster中，DN 1 p时钟神经元起着唤醒和睡眠促进作用[6-11]，这表明DN 1 p神经元与下游睡眠和唤醒中心的复杂耦合。然而，DN 1 p神经元调节睡眠的电路逻辑仍然知之甚少。在这里，我们表明，DN 1 p神经元可以分为两个形态上不同的子集。来自一个子集的投影围绕大脑间部，这是先前定义的昼夜节律输出区域[12]。相比之下，第二个子集也将突触前末端发送到视觉处理中心，即前视结节（AOTU）[13]。在AOTU内，我们发现DN 1 p神经元抑制一类用于促进巩固睡眠的结节延髓（TuBu）神经元。这些TuBu神经元进而与椭球体的R神经元形成突触连接，椭球体是与视觉特征检测、运动、空间记忆和睡眠稳态相关的区域[14-17]。我们的研究结果定义了DN 1 p神经元的第二个输出臂，并建议TuBu神经元作为睡眠驱动的调节器的作用。
Circadian clocks play conserved roles in gating sleep and wake states throughout the day-night cycle [1-5]. In the fruit fly Drosophila melanogaster, DN1 p clock neurons have been reported to play both wake- and sleep-promoting roles [6-11], suggesting a complex coupling of DN1p neurons to downstream sleep and arousal centers. However, the circuit logic by which DN1p neurons modulate sleep remains poorly understood. Here, we show that DN1p neurons can be divided into two morphologically distinct subsets. Projections from one subset surround the pars intercerebralis, a previously defined circadian output region [12]. In contrast, the second subset also sends presynaptic termini to a visual processing center, the anterior optic tubercle (AOTU) [13]. Within the AOTU, we find that DN1p neurons inhibit a class of tubercular-bulbar (TuBu) neurons that act to promote consolidated sleep. These TuBu neurons in turn form synaptic connections with R neurons of the ellipsoid body, a region linked to visual feature detection, locomotion, spatial memory, and sleep homeostasis [14-17]. Our results define a second output arm from DN1 p neurons and suggest a role for TuBu neurons as regulators of sleep drive.