Paradoxical sleep onset

Boissard, R., Gervasoni, D., Schmidt, M. H. et al (2002). The rat ponto-medullary network responsible for paradoxical sleep onset and maintenance a combined microinjection and functional neuroanatomical study. Eur. J. Neurosci 16, 1959-73. 

Figure 4.2 Model of the network responsible for paradoxical sleep onset and maintenance Abbreviations DRN, dorsal raphe nucleus 5-HT, serotonin LC, locus coeruleus NA, noradrenaline LDT, laterodorsal tegmental nucleus Ach, acetylcholine Me, magnocellular reticular nucleus Gly glycine DPMe, deep mesencephalic reticular nucleus PAG, periaqueductal gray DPGi, dorsal paragigantocellular reticular nucleus PPT, pedunculopontine nucleus PRN, pontine reticular nucleus SLD, sublaterodorsal nucleus Glu, glutamate Pef/HLA perifornical/lateral hypothalamic area Hcrt, hypocretin (i.e. orexin).

Boissard, R., Fort, P., Gervasoni, D., Barbagli, B. Luppi, P. H. (2003). Localization of the GABAergic and non-GABAergic neurons projecting to the sublaterodorsal nucleus and potentially gating paradoxical sleep onset. Eur. J. Neurosci. 18, 1627-39. 

From such experimental evidence one may infer that in animals, and possibly in man, LSD-25 in l°w doses leads to an arousal state that can last for several hours. In view of the more recent information about paradoxical sleep, a somewhat different conclusion may be justified. An "arousal" pattern in the EEG does not necessarily signal the onset of arousal, but may just as well indicate the phase of paradoxical sleep. This suggests that in dream sleep, or REM sleep, the cerebral cortex is physiologically in a state similar to that... 

In man, oral administration of TP reduces the duration of the first phase of slow-wave (non-dreaming) sleep and provokes an abnormally early onset of the second phase of paradoxical (dreaming, rapid-eye-movement) sleep. In patients with narcolepsy, where paradoxical sleep is the first phase, this phase is prolonged. In both cases TP effects are blocked by methyiergidel28 Methysergide, an antagonist of HT, blocks the early onset of dreaming sleepl j it also causes in-somnia 2. ... 

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