Abstract Introduction Narcolepsy type 1 (NT1) is caused by selective loss of orexinergic neurons. Although narcolepsy typically begins in childhood or adolescence, most mouse models induce the orexin peptides neurons from birth. To generate a model that reflects acquired human NT1, we produced recombinant mice expressing diphtheria toxin receptor (DTR) driven prepro-orexin promoter (orexinDTR m...

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...

The number of hypothalamic neuropeptides that have been implicated in the regulation of feeding has grown steadily over recent years (Inui, 1999). Many of these reduce food intake but some increase it. These are neuropeptide Y, Agouti-related protein (a natural antagonist of the melanocortin-4 receptor), melanin-concentrating hormone, galanin and the orexins. Neuropeptide Y and Agouti-related p...

Orexins are hypothalamic neuropeptides, which play important roles in the regulation and maintenance of sleep/wakefulness states and energy homeostasis. To evaluate whether alterations in orexin system is associated with the sleep/wakefulness abnormalities observed in obesity, we examined the mRNA expression of prepro-orexin, orexin receptor type 1 (orexin 1r), and orexin receptor type 2 (oxexi...

We showed previously that OX(1) orexin receptor stimulation produced a strong (3)H overflow response from [(3)H]arachidonic acid (AA)-labeled cells. Here we addressed this issue with a novel set of tools and methods, to distinguish the enzyme pathways responsible for this response. CHO-K1 cells heterologously expressing human OX(1) receptors were used as a model system. By using selective pharm...

The loss of orexin neurons in humans is associated with the sleep disorder narcolepsy, which is characterized by excessive daytime sleepiness and cataplexy. Mice lacking orexin peptides, orexin neurons, or orexin receptors recapitulate human narcolepsy phenotypes, further highlighting a critical role for orexin signaling in the maintenance of wakefulness. Despite the known role of orexin neuron...

Orexin neurons in the lateral hypothalamus (LH)/perifornical area (PFA) are known to promote food intake as well as provide excitatory influence on the dopaminergic reward pathway. Dopamine (DA), in turn, inhibits the reward pathway and food intake through its action in the LH/PFA. However, the cellular mechanism by which DA modulates orexin neurons remains largely unknown. Therefore, we examin...

The number of hypothalamic neuropeptides that have been implicated in the regulation of feeding has grown steadily over recent years (Inui, 1999). Many of these reduce food intake but some increase it. These are neuropeptide Y, Agouti-related protein (a natural antagonist of the melanocortin-4 receptor), melanin-concentrating hormone, galanin and the orexins. Neuropeptide Y and Agouti-related p...

At present, secretin and its receptor have only been identified in mammals, and the origin of this ligand-receptor pair in early vertebrates is unclear. In addition, the elusive similarities of secretin and orexin in terms of both structures and functions suggest a common ancestral origin early in the vertebrate lineage. In this article, with the cloning and functional characterization of secre...

INTRODUCTION Epilepsy is a neural disorder in which abnormal plastic changes during short and long term periods lead to increased excitability of brain tissue. Kindling is an animal model of epileptogenesis which results in changes of synaptic plasticity due to repetitive electrical or chemical sub-convulsive stimulations of the brain. Lateral hypothalamus, as the main niche of orexin neurons w...