Sleep medicine reviews
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Sleep medicine reviews · Oct 2010
ReviewElectrical stimulation of the hypoglossal nerve in the treatment of obstructive sleep apnea.
Upper airway occlusion in obstructive sleep apnea has been attributed to a decline in pharyngeal neuromuscular activity occurring in a structurally narrowed airway. Surgical treatment focuses on the correction of anatomic abnormalities, but there is a potential role for activation of the upper airway musculature, especially with stimulation of the hypoglossal nerve and genioglossus muscle. ⋯ We also present results from eight obstructive sleep apnea patients with a fully implanted system for hypoglossal nerve stimulation, demonstrating an improvement in upper airway collapsibility and obstructive sleep apnea severity. Future research, including optimization of device features and stimulation parameters as well as patient selection, is necessary to make hypoglossal nerve stimulation a viable alternative to positive airway pressure therapy and upper airway surgical procedures.
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Sleep medicine reviews · Oct 2010
ReviewThe structure of the dorsal raphe nucleus and its relevance to the regulation of sleep and wakefulness.
Serotonergic (5-HT) cells in the rat dorsal raphe nucleus (DRN) appear in topographically organized groups. Based on cellular morphology, expression of other neurotransmitters, afferent and efferent connections and functional properties, 5-HT neurons of the DRN have been grouped into six cell clusters. The subdivisions comprise the rostral, ventral, dorsal, lateral, caudal and interfascicular parts of the DRN. ⋯ At the level of the DRN the 5-HT(2A) and 5-HT(2C) receptor-containing cells are predominantly GABAergic interneurons and projection neurons. Within the boundaries of the DRN the 5-HT(3) receptor is expressed by, among others, glutamatergic interneurons. 5-HT(7) receptors in the DRN are not localized to serotonergic neurons but, at least in part, to GABAergic cells and terminals. The complex structure of the DRN may have important implications for neural mechanisms underlying 5-HT modulation of wakefulness and REM sleep.
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Sleep medicine reviews · Oct 2010
ReviewThe role of dorsal raphe nucleus serotonergic and non-serotonergic neurons, and of their receptors, in regulating waking and rapid eye movement (REM) sleep.
Based on electrophysiological, neurochemical, genetic and neuropharmacological approaches it is currently accepted that serotonin (5-HT) functions to promote waking (W) and to inhibit rapid-eye movement sleep (REMS). The serotonin-containing neurons of the dorsal raphe nucleus (DRN) provide part of the serotonergic innervation of the telencephalon, diencephalon, mesencephalon and rhombencephalon of laboratory animals and man. The DRN has been subdivided into several clusters on the basis of differences in cellular morphology, expression of other neurotransmitters and afferent and efferent connections. ⋯ In contrast, microinjection of 5-HT(1A) receptor agonists promotes REMS. Similarly, local administration of the melanin-concentrating hormone or the GABA(A) receptor agonist muscimol produces an increase of REMS in the rat. Presently, there are no data on the effect of local infusion into the DRN of noradrenergic, dopaminergic, histaminergic, orexinergic and cholinergic agonists on sleep variables in laboratory animals.