Plasma Orexin-A Levels in Obstructive Sleep Apnea-Hypopnea Syndrome
October 16th, 2014 by admin | Posted in Health Care
Orexin and orexin receptors are present in the CNS. The effects of orexin peptides have been uniformly reported as excitatory, and the posterior hypothalamus containing orexin neurons has been implicated in arousal state control. Therefore, it is probable that the orexin system may have a neuromodulatory effect on arousal states. The aim of the present study was to investigate the relationship between plasma orexin-A levels and arousals from sleep in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).
Plasma orexin-A levels were higher in patients with OSAHS compared with those in control subjects (p < 0.05). Plasma orexin-A levels correlated positively, but weakly, with the arousal index (r = 0.51; p < 0.05) and the AHI (r = 0.52; p < 0.05). However, plasma orexin-A levels did not relate to age, BMI, Epworth sleepiness scale, PaO2, PaCO2, minimum arterial oxygen saturation (SaO2) during sleep, or mean SaO2 during sleep. Plasma orexin-A levels can be a measure of both AHI and arousal index.
The hypocretins, subsequently described as orex-ins, were initially implicated in the control of food intake. Appetite and feeding behavior are regulated by many neurotransmitters, and the orexins have been identified as a class of neuropeptides that stimulate food intake. Immunohistochemical studies indicated that orexin-immunoreactive nerve fibers project widely in the CNS, suggesting that orexins are multifunctional. Apart from participating in the regulation of food intake, orexins have been implicated in other biological systems, such as CNS regulation of cardiovascular and autonomic systems. Research has shown that the orexin system participates in the sleep-wake cycle and in the sleep disorder narcolepsy Canadian Pharmacy. Chemelli et al reported that orexin knockout mice could serve as a model of human narcolepsy, and that orexin neurons play a role in controlling arousal in the cortical activation system. Hagan et al demonstrated that orexins activate locus ceruleus neurons and increase arousal in rats. These studies suggested that orexin stimulated the arousal response, although the precise mechanisms remain undefined.
The aim of the present study was to investigate the relationship between plasma orexin-A levels and arousals from sleep in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). We tested the hypothesis that the amount of sleep fragmentation was significantly associated with plasma orexin-A levels.