Abstract
Orexin (hypocretin) appears to play a role in the regulation of energy balances. Previous reports have indicated that orexin-containing neurons are found only in the lateral hypothalamic (LH) area. We show that a subset of neurons in the gut which also express leptin receptors display orexin-like immunoreactivity and express functional orexin receptors. Orexin excites secretomotor neurons in the guinea pig submucosal plexus and increases motility. Moreover, fasting upregulates the phosphorylated form of cAMP response element-binding protein (pCREB) in orexin-immunoreactive neurons, indicating a functional response to food status in these cells. Together, these data suggest that orexin in the gut may play an even more intimate role in regulating energy homeostasis than it does in the CNS.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Axons / metabolism
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Carrier Proteins / biosynthesis*
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Carrier Proteins / pharmacology
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Carrier Proteins / physiology*
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Cyclic AMP Response Element-Binding Protein / metabolism
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Digestive System / innervation
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Digestive System / metabolism*
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Digestive System Physiological Phenomena
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Enteric Nervous System / physiology
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Enteroendocrine Cells / metabolism
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Gastrointestinal Motility / drug effects
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Gastrointestinal Motility / physiology
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Hunger / physiology
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Immunohistochemistry
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Intestine, Small / innervation
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Intestine, Small / metabolism
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Intracellular Signaling Peptides and Proteins*
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Mice
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Mice, Inbred C57BL
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Neurons / metabolism
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Neuropeptides / biosynthesis*
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Neuropeptides / pharmacology
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Neuropeptides / physiology*
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Orexin Receptors
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Orexins
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Protein Precursors / biosynthesis
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Protein Precursors / genetics
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RNA, Messenger / biosynthesis
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RNA, Messenger / genetics
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Rats
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Rats, Sprague-Dawley
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Receptors, G-Protein-Coupled
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Receptors, Neuropeptide / biosynthesis
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Receptors, Neuropeptide / genetics
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Reverse Transcriptase Polymerase Chain Reaction
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Synapses / metabolism
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Synapses / physiology
Substances
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Carrier Proteins
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Cyclic AMP Response Element-Binding Protein
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Intracellular Signaling Peptides and Proteins
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Neuropeptides
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Orexin Receptors
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Orexins
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Protein Precursors
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RNA, Messenger
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Receptors, G-Protein-Coupled
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Receptors, Neuropeptide