Document Detail

Suppression of third ventricular NPY-elicited feeding following medullary reticular formation infusions of muscimol.
MedLine Citation:
PMID:  20364882     Owner:  NLM     Status:  MEDLINE    
The appetitive component of feeding is controlled by forebrain substrates, but the consummatory behaviors of licking, mastication, and swallowing are organized in the brainstem. The target of forebrain appetitive signals is unclear but likely includes regions of the medullary reticular formation (RF). This study was undertaken to determine the necessity of different RF regions for mastication induced by a descending appetitive signal. We measured solid food intake in response to third ventricular (3V) infusions of the orexigenic peptide neuropeptide Y 3-36 in awake, freely moving rats and determined whether focal RF infusions of the GABAA agonist muscimol suppressed eating. RF infusions were centered in either the lateral tegmental field, comprising the intermediate (IRt) and parvocellular (PCRt) RF, or in the nucleus gigantocellularis (Gi). Infusions of NPY 3-36 (5 microg/5 microl) into 3V significantly increased feeding of solid food over a 90-min period compared with the noninfused condition (4.3 g +/- 0.56 vs. 0.57 g +/- 0.57, p < .001). NPY 3-36-induced food intake was suppressed (1.7 g +/- 0.48) by simultaneous infusions of muscimol (0.6 mM/100 nl) into the IRt/PCRt (p < .01). Coincident with the decrease in feeding was a decrease in the amplitude of anterior digastric muscle contractions in response to intraoral sucrose infusions. In contrast, infusions of muscimol into Gi had no discernible effect on food intake or EMG amplitude. These data suggest that the IRt/PCRt is essential for forebrain-initiated mastication, but that the Gi is not a necessary link in this pathway.
Joseph B Travers; Kenneth Herman; Susan P Travers
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Behavioral neuroscience     Volume:  124     ISSN:  1939-0084     ISO Abbreviation:  Behav. Neurosci.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-06     Completed Date:  2010-06-24     Revised Date:  2011-08-01    
Medline Journal Info:
Nlm Unique ID:  8302411     Medline TA:  Behav Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  225-33     Citation Subset:  IM    
Division of Oral Biology, College of Dentistry, The Ohio State University, Columbus, OH 43210, USA.
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MeSH Terms
Appetite Stimulants / administration & dosage,  antagonists & inhibitors*,  pharmacology
Drug Interactions
Eating / drug effects*,  physiology
GABA Agonists / administration & dosage,  pharmacology*
Injections, Intraventricular
Mastication / drug effects,  physiology
Medulla Oblongata / drug effects*,  physiology
Muscimol / administration & dosage,  pharmacology*
Neuropeptide Y / administration & dosage,  antagonists & inhibitors*,  pharmacology
Peptide Fragments / administration & dosage,  antagonists & inhibitors*,  pharmacology
Rats, Sprague-Dawley
Reticular Formation / drug effects*,  physiology
Stomach / drug effects,  physiology
Sucrose / pharmacology
Grant Support
Reg. No./Substance:
0/Appetite Stimulants; 0/GABA Agonists; 0/Neuropeptide Y; 0/Peptide Fragments; 0/neuropeptide Y (3-36); 2763-96-4/Muscimol; 57-50-1/Sucrose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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