Cycles and Sleep

Lucas, E. A. Sterman, M. B. (1975). Effect of a forebrain lesion on the polycyclic sleep-wake cycle and sleep-wake patterns in the cat. Exp. Neurol. 46, 368-88. 

Barnes, B.M., O.Toien, J. Blake, D. Grahn, H.C. Heller, and D.M. Edgar (1999). Hibernation in black bears temperature cycles and sleep. FASEB J. 13 A740. 

Neurons within the SCN innervate those hypothalamic areas which have a crucial role in the regulation of the reproductive cycle, mood and sleep/arousal, as well as regions such as the basal forebrain and the thalamus which help to determine the state of arousal. They also project to the pineal gland to govern the synthesis and release of... 

The precise role of melatonin in sleep and waking is uncertain but it seems to act as a go-between for the light and biological cycles and evidence suggests that it has a reciprocal relationship with the SCN (Fig. 22.3). Its actions are mediated by (MLi) receptors which are found predominantly in the SCN as well as thalamic nuclei and the anterior pituitary. These are G protein-coupled receptors, with seven transmembrane domains, that inhibit adenylyl cyclase. Their activation by melatonin, or an MLi agonist such as 2-iodomelatonin, restores the impaired circadian cycle in aged rats. 

Mg removal by seawater cycling through midoceanic ridges has been estimated by several workers. They vary widely and are —2.4 x 10 g/year (Mottl, 1983), —6.5 x 10 g/year (Wolery and Sleep, 1976), and —3.9 x 10 mol/year (Elderfield and Schultz, 1996). 

Bodosi, B., Gardi, J., Hajdu, I. et al. (2004). Rhythms of ghrelin, leptin, and sleep in rats effects of the normal diurnal cycle, restricted feeding, and sleep deprivation. Am. J. Physiol Regul. Integr. Comp. Physiol 287, R1071-9. 

With this in mind, the search for molecular markers that define populations of neurons in areas important for arousal is clearly warranted. In this chapter we describe the identification of four peptidergic systems that modulate different aspects of the sleep-wakefulness cycle. The success of this strategy demonstrates the need for new markers of neuronal cell types, which may define populations of neurons critical for our understanding of cortical activity and sleep. 

Wu, M. F., John, J., Boehmer, L. N. et al. (2004). Activity of dorsal raphe cells across the sleep-waking cycle and during cataplexy in narcoleptic dogs. J. Physiol. 554, 202-15. 

Fig. 4. The normal nocturnal migrating motor complex (MMC) recorded in the duodenum (upper tracing) and proximal jejunum (lower tracing) of a 91-year-old healthy woman. A short period is shown in high resolution in the lower panel. Phase III is preceded by phase II with some contractile activity, usually limited during sleep, and succeeded by contractile quiescence, phase I. The sequence of phase III-I-II-III constitutes one MMC cycle, and recurs during fasting (modified with permission from Husebye and Engedal [79]).

Many clinically available drugs that modify sleep-wake cycles and appetite act through the histaminergic system 262... 

Ramelteon (Rozerem). Recently approved by the FDA for treatment of insomnia in the US, ramelteon acts via a completely novel mechanism of action, that is, stimulating so-called melatonin Ti and T2 receptors in the brain s suprachiasmatic nucleus (SCN). The SCN is regarded as the body s master clock that regulates the sleep-wake cycle and other circadian rhythms. The effects of ramelteon in some respects mimic those of melatonin. Ramelteon, in clinical trials, administered at bedtime doses of 8 mg, outperformed placebo with respect to several indices of sleep disturbance (see Table 9.4). 

AD subjects have a higher prevalence of sleep disturbances than normal elderly, including sleep fragmentation, advancement of the sleep-wake cycle, and decreased amounts of slow wave and rapid-eye movement (REM) sleep (Prinz et al., 1982 Reynolds et al., 1988 Bliwise et al., 1989). Sleep-wake cycle disruption in AD has been associated with a greater burden of neuropsychiatric disturbances (Rebok et al., 1991 Ancoli-Israel et al., 1994), particularly apathy and delusions (Kaufer et al., 2001). Several studies have observed a relationship between the degree of intellectual impairment and REM sleep abnormalities (Prinz et al., 1982 Vitiello et al., 1984 Moe et al., 1995), underscoring the role of REM sleep in memory consolidation (Wilson McNaughton, 1994). 

SALZARULO, Piero and Gianluca FICCA (eds.) Awakening and Sleep-Wake Cycle Across Development, n.y.p. 

Lu J, Zhang YH, Chou TC et al 2001 Contrasting effects of ibotenate lesions of the paraventricular nucleus and subparaventricular zone on sleep-wake cycle and temperature regulation. J Neurosci 21 4864-4874... 

One of the most consistent findings is the sleep disturbance that often precedes and may even trigger a manic phase ( 46). Studies on circadian rhythms have demonstrated that many aspects of the sleep cycle are phase-advanced in mania (i.e., occur earlier than normal), and often these patterns resemble the free-running rhythms seen in normal individuals who are removed from all time cues. In addition, there is a blunting of amplitude and a doubling of the sleep-wake cycle up to 48 hours. Lithium is known to delay the sleep-wake cycle and often slow such free-running rhythms, which in turn are partly modulated by neurotransmitters such as NE, 5-HT, and acetylcholine. Further, manipulation of the sleep-wake cycle may prevent a manic episode or be used to treat the depressive phase (e.g., sleep deprivation therapy see also the section Experiments in Chapter 8). 

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