Noradrenaline neurons sleep-wake

Cape EG and Jones, BE (1998) Differential modulation of high-frequency gamma-electroencephalogram activity and sleep-wake state by noradrenaline and serotonin microinjections into the region of cholinergic basalis neurons. J. Neurosci. 18 2653-2666. 

Some less obvious phenomena of catecholamine transport and biosynthesis further illustrate the complexities of deciphering how efferents from midbrain dopamine neurons contribute to sleep-wake regulation. The plasma membrane norepinephrine transporter (NET), which is responsible for the uptake of extracellular noradrenaline, can also readily transport dopamine, and does so in vivo. This... 

Grivel, J., Cvetkovic, V., Bayer, L. el al. (2005). The wake-promoting hypocretin/orexin neurons change their response to noradrenaline after sleep deprivation. J. Neurosci 25, 4127-30. 

Some arousal-related neurotransmitters, including noradrenaline, serotonin, and acetylcholine, feed back to inhibit POA sleep-active neurons. This aspect of the system has been reviewed previously (McGinty Szymusiak, 2000 Saper et al., 2001). Therefore, once sleep-active neurons are activated, arousal-related neurons are inhibited, and inhibitory control of sleep-active neurons by arousal systems is reduced. In this way, sleep onset is facilitated. That is, the mutually inhibitory systems can switch more quickly from wake to sleep, and back. These mutually inhibitory interactions also promote stability of both waking and sleep. 

Figure 2.4 Flip-flop switch model of wake and slow wave sleep active systems. Mutually inhibitory connections exist between GABAergic/Galaninergic slow wave sleep active neurons in the ventrolateral preoptic area (VLPO) of the anterior hypothalamus and aminergic neurons in the hypothalamus (histamine (HA) neurons in the tuberomammillary nucleus (TMN)) and brainstem (serotonin (5-HT) neurons in the dorsal raphe (DR) and noradrenaline (NA) neurons in the locus coeruleus (LC)). Orexinergic neurons in the perifornical hypothalamus (PFH) stabilize the waking state via excitation of the waking side of the flip-flop switch (aminergic neurons).

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