GABAergic brainstem

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).

Forebrain neurons would not be necessary for PS onset and maintenance. However, hypocretin and MCH hypothalamic neurons would participate in the homeostasis of PS through reciprocal connections and their respective excitatory and inhibitory projections on the brainstem monoaminergic and GABAergic PS-off neurons. 

Yuan CS, Attele AS, Wu JA, Liu D. (1998). Modulation of American ginseng on brainstem GABAergic effects in rats. J Ethnopharmacol. 62(3) 215-22. 

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