Part of the
Advances in Experimental Medicine and Biology
book series (AEMB, volume 551)
Serotonergic Receptors and Effects in Hypoglossal and Laryngeal Motoneurons
Semi-Quantitative Studies in Neonatal and Adult Rats
Respiratory motoneurons of the brainstem express multiple receptors for serotonin (5-HT).1, 2, 3, 4, 5, 6, 7 Some of these receptors mediate excitatory effects (e.g., type 2), whereas others (e.g., type 1) are inhibitory, yet the net effect of 5-HT applied onto motoneurons of mature animals is excitation, and antagonism of endogenous serotonergic effects suppresses the activity in brainstem respiratory motoneurons.8, 9, 10 Since all brainstem serotonergic neurons consistently exhibit decreased activity during slow-wave sleep and are silenced during rapid eye movement (REM) sleep, it has been proposed that a withdrawal of serotonergic excitation from brainstem respiratory motoneurons may play an important role in sleep-related decrements of their activity.8 In individuals with anatomical abnormalities of their upper airway, such decrements may cause nocturnal upper airway obstructions, leading to the obstructive sleep apnea syndrome (reviewed in ref. 11).
Key wordsdevelopment motoneurons serotonin receptors sleep single-cell RT-PCR
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