AsianScientist (July 5, 2017) – Scientists from the International Institute for Integrative Sleep Medicine at the University of Tsukuba have shown that activating neurons linked to anxiety can immediately wake sleeping mice. Their findings, published in The Journal of Neuroscience, shed light on the connection between anxiety and sleep disorders.
Anxiety, stress and excitement are known to affect wakefulness and can even cause insomnia. Such emotions may be triggered by dangerous encounters or new environments that require animals to shift their behavior and adopt a heightened vigilant state.
The bed nucleus of the stria terminalis (BNST), a part of the extended amygdala, is connected to various brain regions including the relay nuclei of the autonomic nervous system, the hypothalamic regions and the central nucleus of the amygdala. Thus, the BNST is thus responsible for regulating endocrine and autonomic reactions in response to emotionally-salient stimuli, including anxiety and fear.
In this study, the researchers used optogenetic methods to excite GABAergic neurons within the BNST of mice during non-rapid eye movement (NREM) sleep. This caused the mice to immediately adopt a wakeful state, even without the function of neuropeptides normally involved in maintaining wakefulness called orexins. Notably, stimulation of the same neurons during REM sleep did not show any effects on sleep and wakefulness states.
Prolonged excitation of GABAergic neurons in the BNST evoked a longer-lasting state of wakefulness. This sustained wakefulness was disrupted when mice were given a dose of a dual orexin receptor blocker called DORA 22 in advance, highlighting the importance of orexins in maintaining wakefulness.
“Our study revealed a role of the BNST GABAergic system in sleep and wakefulness control, especially in shifting animals’ behavioral states from NREM sleep to wakefulness,” said Dr. Takeshi Sakurai, Vice Director of the International Institute for Integrative Sleep Medicine, University of Tsukuba.
“It also provides an important insight into the pathophysiology of insomnia and the role of orexin in arousal regulation, which will hopefully lead to the first step to develop remedies for sleep disorders,”
The article can be found at: Kodani et al. (2017) Excitation of GABAergic neurons in the Bed Nucleus of the Stria Terminalis Triggers Immediate Transition from Non-rapid Eye Movement Sleep to Wakefulness in Mice.
Source: University of Tsukuba; Photo: Shutterstock.
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