Orexins information, review and research studies
Orexin peptides act as regulators of many functions including the control of sleep-wake states, breathing, and central chemosensitivity. Orexin signaling is directly involved in the control of upper airway openness in particular during wakefulness, whereas decreasing activity of orexinergic neurons may contribute to upper airway collapse during sleep causing obstructive sleep apnea. See insomnia cures for practical information on how to treat insomnia naturally.
Orexins are neuropeptides that are localized in neurons within the lateral hypothalamus and regulate feeding behavior. The lateral hypothalamus plays an important role in not only feeding but also in the central regulation of gut function. Orexins act in the central nervous system to regulate gastrointestinal functions. Centrally administered orexin or endogenously released orexin in the brain potently stimulates gastric acid secretion in rats. The vagal cholinergic pathway is involved in the orexin-induced stimulation of acid secretion. Brain orexin may be involved in the development of depression and functional gastrointestinal disorders, which are frequently accompanied by inhibition of gut function, because lack of orexin activity might cause the inhibition of gastric physiological processes and evoke a depressive state.
Plasma orexin-A levels in postmenopausal women:
possible interaction with estrogen and correlation with cardiovascular risk
BJOG. 2010. El-Sedeek MS, Korish AA. Department of Obstetrics and Gynaecology, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
Please cite this paper as: El-Sedeek M, Korish A. Plasma orexin-A levels in postmenopausal women: possible interaction with estrogen and correlation with cardiovascular risk status. BJOG 2010.
To assess plasma orexin-A levels in a group of postmenopausal women not receiving estrogen-replacement therapy (ERT), and to compare the values with a group on ERT and a group of reproductive-age women, and to correlate the findings with some cardiovascular risk factors. Design Observational cohort study. Setting Alexandria University Hospital. Population Ninety women, in three groups: a control group of 30 healthy, reproductive-age women, 30 healthy postmenopausal women not receiving ERT, and 30 healthy postmenopausal women on ERT for 6 months. Methods Quantitative clinical assessment as well as laboratory investigations. Main outcome measures Orexin-A levels, serum estradiol, cholesterol, triglycerides, and fasting glucose are the main laboratory outcome measures, whereas blood pressure and weight are the main clinical outcome measures. Results Postmenopausal women not receiving ERT had the highest levels of plasma orexin A (705 mug/dl). Postmenopausal women on ERT had orexin-A levels that were comparable with the control group (233.90 +/- 54.26 versus 243.81 +/- 68.88 mug/dl). Plasma orexin-A levels were directly correlated with blood glucose lipid profile, arterial blood pressure, and body mass index. Conclusions Higher orexin-A levels are associated with hypoestrogenism, and are partially reversed by ERT. A possible inhibitory effect of estrogen on orexin might partially account for its cardioprotective effect.
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