Weight gain is one side effect of many antipsychotic drugs (APDs). A small number of lateral hypothalamic/perifornical area (LH/PFA) neurons express the orexins, peptides that are critically involved in body weight regulation and arousal. We examined the ability of APDs to activate orexin neurons, as reflected by induction of Fos. APDs with significant weight gain liability increased Fos expres...

Neurons containing orexin (hypocretin), or melanin concentrating hormone (MCH) are intermingled with each other in the perifornical and lateral hypothalamus. Each is a separate and distinct neuronal population, but they project to similar target areas in the brain. Orexin has been implicated in regulating arousal since loss of orexin neurons is associated with the sleep disorder narcolepsy. Mic...

Avoiding danger and finding food, which are life-sustaining activities that are regulated by emotion, reward and energy balance, require proper wakefulness. The orexin system controls sleep and wakefulness through interactions with systems that regulate emotion, reward and energy homeostasis. Recent findings have brought about the possibility of novel therapies targeting the orexin system for s...

Orexin A and B are involved in feeding behaviors, and recently fibers containing these peptides were found in the rat olfactory bulb. These fibers, which originate from the lateral and posterior hypothalamus and the perifornical area, are distributed in the glomerular, mitral cell, and granule cell layers. Orexin receptors are mainly expressed by mitral cells. In the present study, RT-PCR exper...

Lateral hypothalamic neuropeptides, orexins, have been recognized as one of the most important regulators of sleep/wakefulness states. Besides, these peptides are also regarded as an important factor that regulates feeding behavior, owing to their localization within the lateral hypothalamic area, the classic “feeding center”, pharmacological activities, and the fact that prepro-orexin mRNA is ...

Orexin-A and orexin-B (the hypocretins) are recently described neuropeptides suggested to have a physiological role in the regulation of food intake in the rat. We compared the orexigenic effect of the orexins administered intracerebroventricular (ICV) with other known stimulants of food intake, one strong, neuropeptide Y (NPY), and two weaker, melanin-concentrating hormone (MCH) and galanin. O...

Orexin A and B, orexigenic peptides produced primarily by the lateral hypothalamus that signal through two G protein-coupled receptors, orexin receptors 1/2, have been implicated in the regulation of several physiological processes in mammals. In avian (nonmammalian vertebrates) species; however, the physiological roles of orexin are not well defined. Here, we provide novel evidence that not on...

Orexins have previously been shown to promote wakefulness, regulate lipid metabolism and participate in energy homeostasis. The aim of the study was to determine the relationship between plasma orexin-A and body composition in COPD in-patients with hypercapnic respiratory failure. 40 patients with hypercapnic respiratory failure and 22 healthy individuals were enrolled prospectively in this stu...

Hypothalamic orexin/hypocretin neurons recently emerged as key orchestrators of brain states and adaptive behaviors. They are critical for normal stimulation of wakefulness and breathing: Orexin loss causes narcolepsy and compromises vital ventilatory adaptations. However, it is unclear how orexin neurons generate appropriate adjustments in their activity during changes in physiological circums...

Previous results have suggested that orexins causes a rise of intracellular free calcium ([Ca(2+)](i)) in cultured rat dorsal root ganglion (DRG) neurons, implicating a role in nociception, but the underlying mechanism is unknown. Hence, the aim of the present study was to investigate whether the orexins-mediated signaling involves the PKC pathways in these sensory neurons. Cultured DRG neurons...