Galanin and feeding behavior: Relation to norepinephrine and neuropeptide Y.
Item
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Title
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Galanin and feeding behavior: Relation to norepinephrine and neuropeptide Y.
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Identifier
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AAI9009752
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identifier
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9009752
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Creator
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Kyrkouli, Stavroula E.
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Contributor
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Adviser: Richard Bodnar
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Date
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1989
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Physiological | Biology, Neuroscience
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Abstract
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The neuropeptide, galanin (GAL), is widely distributed in the gut and brain. It is most concentrated in the hypothalamus and, in particular, the paraventricular nucleus (PVN) where receptor sites for {dollar}\sp{lcub}125{rcub}{dollar}I-GAL may also be found. This peptide has recently been found to elicit feeding in satiated rats after medial hypothalamic administration. Moreover, it is found to coexist with norepinephrine (NE) in the PVN, a site and neurotransmitter believed to be important in the control of natural feeding behavior.;Based on these findings, this dissertation investigates the possibility that GAL influences food intake through its actions in the PVN and, in particular, via its direct interaction with the noradrenergic system localized in this nucleus. The results strongly suggest that GAL induces feeding, in part, through the release of endogenous NE in the PVN. This is in contrast to the action of another hypothalamic peptide, neuropeptide Y (NPY). While this peptide is also a strong stimulant of food intake and coexists with NE in the PVN, the results suggest that it acts independently of, or possibly even antagonistically with, this catecholamine.;These results were obtained through three experiments, that involved brain cannula-mapping procedures, pharmacological tools, and the microdialysis technique in combination with high performance liquid chromatography (HPLC) with electrochemical detection (ED).;The findings with GAL and NPY suggest the existence of two types of peptide-amine interactions in the PVN. These are: a cooperative interaction, whereby GAL stimulates the release of NE and through this amine regulates feeding; and an antagonistic interaction, whereby NPY and NE may actually suppress each other's action. In light of other findings, it is proposed that GAL has a specific physiological function in modulating natural feeding behavior, particularly at the onset of the animal's active (dark) cycle. At this time, GAL is believed to play a role specifically in the potentiation of carbohydrate ingestion, acting through the enhanced release of NE in the PVN.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
