Department of Physiology, University of Lausanne, CH-1005, Lausanne, Switzerland.
Center for Integrative Genomics, University of Lausanne, CH-1015, Lausanne, Switzerland.
Sci Rep. 2018 Oct 19;8(1):15474. doi: 10.1038/s41598-018-33069-8.
Noradrenaline (NA) and hypocretins/orexins (HCRT), and their receptors, dynamically modulate the circuits that configure behavioral states, and their associated oscillatory activities. Salient stimuli activate spiking of locus coeruleus noradrenergic (NA) cells, inducing NA release and brain-wide noradrenergic signalling, thus resetting network activity, and mediating an orienting response. Hypothalamic HCRT neurons provide one of the densest input to NA cells. To functionally address the HCRT-to-NA connection, we selectively disrupted the Hcrtr1 gene in NA neurons, and analyzed resulting (Hcrtr1) mice', and their control littermates' electrocortical response in several contexts of enhanced arousal. Under enforced wakefulness (EW), or after cage change (CC), Hcrtr1 mice exhibited a weakened ability to lower infra-θ frequencies (1-7 Hz), and mount a robust, narrow-bandwidth, high-frequency θ rhythm (~8.5 Hz). A fast-γ (55-80 Hz) response, whose dynamics closely parallelled θ, also diminished, while β/slow-γ activity (15-45 Hz) increased. Furthermore, EW-associated locomotion was lower. Surprisingly, nestbuilding-associated wakefulness, inversely, featured enhanced θ and fast-γ activities. Thus HCRT-to-NA signalling may fine-tune arousal, up in alarming conditions, and down during self-motivated, goal-driven behaviors. Lastly, slow-wave-sleep following EW and CC, but not nestbuilding, was severely deficient in slow-δ waves (0.75-2.25 Hz), suggesting that HCRT-to-NA signalling regulates the slow-δ rebound characterizing sleep after stress-associated arousal.
去甲肾上腺素(NA)和食欲肽/下丘脑泌素(HCRT)及其受体,动态调节构成行为状态的回路及其相关的振荡活动。显著刺激激活蓝斑去甲肾上腺素能(NA)细胞的放电,诱导 NA 释放和全脑去甲肾上腺素能信号,从而重置网络活动,并介导定向反应。下丘脑食欲肽神经元为 NA 细胞提供最密集的输入之一。为了从功能上解决 HCRT-NA 连接,我们选择性地在 NA 神经元中破坏了 Hcrtr1 基因,并分析了由此产生的(Hcrtr1)小鼠及其对照同窝仔鼠在几种增强觉醒状态下的电皮质反应。在强制觉醒(EW)或笼更换(CC)后,Hcrtr1 小鼠表现出降低亚θ频率(1-7 Hz)的能力减弱,并且无法产生强大的、窄带宽、高频θ节律(~8.5 Hz)。快速γ(55-80 Hz)反应,其动力学与θ密切平行,也减弱,而β/慢γ活动(15-45 Hz)增加。此外,EW 相关的运动减少。令人惊讶的是,巢筑相关的觉醒,相反,表现出增强的θ和快速γ活动。因此,HCRT-NA 信号可能精细调节唤醒,在警报情况下增加,而在自主、有目标驱动的行为中减少。最后,EW 和 CC 后的慢波睡眠(而非巢筑相关的觉醒)严重缺乏慢δ波(0.75-2.25 Hz),表明 HCRT-NA 信号调节与应激相关唤醒后睡眠相关的慢δ反弹。