Objective(s): Intracerebroventricular injection of orexin-A (hypocretin-1) antagonist has been shown to inhibit stress-induced analgesia. However the locations of central sites that may mediate these effects have not been totally demonstrated. This study was performed to investigate the role of rostral ventromedial medulla (RVM) orexin receptor 1 in stress-induced analgesia (SIA). Materials and...

The cytoprotective enzyme heme oxygenase-1 (HO-1) influences endothelial cell survival, proliferation, inflammatory response, and angiogenesis in response to various angiogenic stimuli. In this study, we investigate the involvement of HO-1 in the angiogenic activity of orexin-A. We showed that orexin-A stimulates expression and activity of HO-1 in human umbilical vein endothelial cells (HUVECs)...

Orexin (or hypocretin) is synthesized exclusively in dorsomedial, perifornical, and lateral hypothalamus (LH). These neurons are implicated in several functions, including reward processing. We examined the ventral tegmental area (VTA) as a possible site of orexin action for drug preference during protracted morphine abstinence, and studied functional topography of orexin projections to VTA. Ma...

Glycine, a nonessential amino-acid that acts as an inhibitory neurotransmitter in the central nervous system, is currently used as a dietary supplement to improve the quality of sleep, but its mechanism of action is poorly understood. We confirmed the effects of glycine on sleep/wakefulness behavior in mice when administered peripherally. Glycine administration increased non-rapid eye movement ...

UNLABELLED We studied the effects of intracerebroventricular injection of the novel neuropeptide orexin A on electroencephalogram (EEG) and autonomic nervous system activity in rats under isoflurane anesthesia. The administration of orexin A changed burst suppression patterns to arousal patterns on the EEG at 1.0 minimum alveolar anesthetic concentration (MAC) isoflurane and decreased the burst...

Dopamine neurons in the ventral tegmental area (VTA) represent a critical site of synaptic plasticity induced by addictive drugs. Orexin/hypocretin-containing neurons in the lateral hypothalamus project to the VTA, and behavioral studies have suggested that orexin neurons play an important role in motivation, feeding, and adaptive behaviors. However, the role of orexin signaling in neural plast...

In humans, nonexercise activity thermogenesis (NEAT) increases with positive energy balance. The mediator of the interaction between positive energy balance and physical activity is unknown. In this study, we address the hypothesis that orexin A acts in the hypothalamic paraventricular nucleus (PVN) to increase nonfeeding-associated physical activity. PVN-cannulated rats were injected with eith...

Intracerebroventricular (ICV) administration of ghrelin, orexin and neuropeptide Y (NPY) stimulates food intake in goldfish. Orexin and NPY interact with each other in the regulation of feeding, while ghrelin-induced feeding has also shown to be mediated by NPY in the goldfish model. To investigate the interaction between ghrelin and orexin, we examined the effects of a selective orexin recepto...

Cataplexy, a sudden unexpected muscle paralysis, is a debilitating symptom of the neurodegenerative sleep disorder, narcolepsy. During these attacks, the person is paralyzed, but fully conscious and aware of their surroundings. To identify potential neurons that might serve as surrogate orexin neurons to suppress such attacks, the gene for orexin (hypocretin), a peptide lost in most human narco...