AN AUTOIMMUNE ETIOLOGY IS HYPOTHETICALLY INVOLVED IN THE PHYSIOPATHOLOGY OF NARCOLEPSY, ALTHOUGH THERE IS CONFLICTING EVIDENCE.1-4 This disorder is related to abnormalities in the hypothalamic hypocretin (orexin) system with a characteristic deficiency in CSF Hypocretin-1 (Hcrt-1) levels in narcoleptic patients.5 The aim of our study was to investigate the presence of hypothalamic-specific anti...

Orexin/hypocretin neurons play a crucial role in the regulation of sleep/wakefulness, primarily in the maintenance of wakefulness. These neurons innervate wide areas of the brain and receive diverse synaptic inputs including those from serotonergic (5-HT) neurons in the raphe nucleus. Previously we showed that pharmacological application of 5-HT directly inhibited orexin neurons via 5-HT1A rece...

Background and Aim: Orexin-A are hypothalamic neuropeptides contributing to regularization of neuroendocrine homeostasis, feeding behavior sleep-wakefulness rhythm. Blood pressure, sympathetic activation, blood glucose level, metabolic status is controlled by neuropeptide. The present study aimed evaluate the association body mass index with levels in reproductive age group women. Methodology: ...

Hypocretin (orexin) has recently been shown to increase feeding when injected into the brain. Using both rat and primate brains, we tested the hypothesis that a mechanism of hypocretin action might be related to synaptic regulation of the neuropeptide Y (NPY) system. Hypocretin-immunoreactive terminals originating from the lateral hypothalamus make direct synaptic contact with neurons of the ar...

There is now no doubt that hypocretin/orexin (Hcrt) deficiency is the cause of most narcolepsy in humans (1,2). It is also clear that mutations of the Hcrt system cause genetic narcolepsy in several animal species (3,4). Narcolepsy in these Hcrt deficiency situations is characterized by sleepiness during the normally active period and losses of muscle tone during waking periods called cataplexy...

The neuropeptide orexin (hypocretin) increases energy expenditure partially through increasing spontaneous physical activity. The ability of exogenous orexin to alter body weight has never been established, however. We sought to determine whether orexin-A microinjected into the paraventricular nucleus of the hypothalamus (PVN) induced weight loss in rats. Chronic guide cannulae were implanted i...

Sleep influences the cardiovascular, endocrine, and thermoregulatory systems. Each of these systems may be affected by the activity of hypocretin (orexin)-producing neurons, which are involved in the etiology of narcolepsy. We examined sleep in male rats, either hypocretin neuron-ablated orexin/ataxin-3 transgenic (narcoleptic) rats or their wild-type littermates. We simultaneously monitored el...

Hypocretin/orexin modulates sleep-wake state via actions across multiple terminal fields. Within waking, hypocretin may also participate in high-arousal processes, including those associated with stress. The current studies examined the extent to which alterations in neuronal activity, as measured by Fos immunoreactivity, occur within both hypocretin-synthesizing and hypocretin-1 receptor-expre...

The hypothalamic orexin (hypocretin) neuropeptides are associated with the regulation of sleep and feeding, and disturbances in orexinergic neurotransmission lead to a narcoleptic phenotype. Histamine has also been shown to play a role in the regulation of sleep and feeding. Therefore, we studied the relationship between the orexin and histamine systems of the CNS using electrophysiology, immun...