THE PHARMACO-ONTOGENY OF HYPOTHALAMIC RECEPTOR SYSTEMS MEDIATING INDEPENDENT FEEDING IN THE RAT (CATECHOLAMINES, NEUROPEPTIDES, SYNAPTIC RECEPTORS).
Item
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Title
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THE PHARMACO-ONTOGENY OF HYPOTHALAMIC RECEPTOR SYSTEMS MEDIATING INDEPENDENT FEEDING IN THE RAT (CATECHOLAMINES, NEUROPEPTIDES, SYNAPTIC RECEPTORS).
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Identifier
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AAI8708278
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identifier
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8708278
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Creator
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CAPUANO, CHRISTOPHER A.
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Contributor
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Gordon A. Barr
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Date
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1987
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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, Psychobiology
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Abstract
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Studies in adult rats have provided evidence suggesting that two separate catecholamine systems are involved in regulating feeding behavior. The first is a noradrenergic system that stimulates feeding through interaction with alpha-noradrenergic receptors located in the medial (paraventricular) hypothalamic region. The second is an adrenergic and dopaminergic system that suppresses feeding through interaction with beta-adrenergic and dopaminergic receptors located in the lateral (perifornical) hypothalamic region. Further evidence exists that neuropeptides also play a role in hypothalamic regulation of feeding in the rat. Other studies have identified an independent feeding system in the rat pup that mediates ingestion of milk off the nipple and appears to be developmentally continuous with feeding in adult rats. The present research was undertaken to assess the pharmaco-ontogeny of hypothalamic catecholamine and neuropeptide receptor systems mediating independent feeding in the rat. Sated and deprived rat pups ranging in age from 2 to 15 days were stereotaxically implanted with a unilateral cannula directed at the hypothalamic paraventricular nucleus, ventral third ventricle, perifornical hypothalamus or more rostral anterolateral hypothalamus. The next day, pups were implanted with an intra-oral cannula for infusion of milk or water. Following injection of a single dose of either the alpha-noradrenergic receptor agonists norepinephrine or clonidine, the beta-adrenergic receptor agonists epinephrine or salbutamol, the dopaminergic receptor agonist apomorphine, the neuroactive peptides cholecystokinin or neuropeptide Y, or the vehicle, milk or water intake was assessed in a 1 hr test. The results indicated that receptors mediating independent feeding in the rat are behaviorally fuctional prior to the onset of weaning. Except for cholecystokinin, receptors mediating the feeding response to norepinephrine, epinephrine, dopamine and neuropeptide Y neurochemical agents do so as early as 2 days postpartum. Moreover, consistent with studies in adult rats, this work has identified the paraventricular nucleus and perifornical hypothalamus as primary hypothalamic areas in the infant rat that are sensitive to the effects of the neurochemical agents tested. Collectively, the present findings strongly suggest that the independent feeding system in the infant, while not used during normal development, is developmentally continuous with feeding in the adult and represents an appropriate starting point for developmental analysis of neurochemical systems regulating adult feeding behavior in the rat.
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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.
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Program
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Psychology
