| Ibotenic acid lesions reduce noradrenergic activation in ventromedial hypothalamus during hypoglycemia. | |
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MedLine Citation:
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PMID: 16905122 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Noradrenergic and GABAergic systems in the ventromedial hypothalamus (VMH) are activated during hypoglycemia and initiate part of the compensatory counterregulatory response. Norepinephrine (NE) terminals innervating the VMH originate in glucosensing hindbrain areas, but whether NE activity in the VMH is under local control or in the hindbrain is unclear. To elucidate the role of neurons intrinsic to the VMH on NE release in the VMH during hypoglycemia, ibotenic acid (IBO), an NMDA receptor agonist that selectively destroys cell bodies, was used. In a 2 x 2 factorial study, IBO (3-5 microg/0.5 microL) or vehicle was stereotaxically administered into the VMH of male Sprague-Dawley rats. One week later, NE concentration in the VMH was measured by microdialysis during insulin-induced hypoglycemia (2.0 U/kg) or euglycemia (saline control). Baseline levels of NE were not statistically different (p=0.10) in IBO-treated compared with vehicle-treated rats (13.3+/-2.8 nM vs. 7.9+/-1.1 nM). The initial increase in interstitial NE concentration during hypoglycemia in control rats was absent in IBO-treated rats (p<0.01). In IBO-treated hypoglycemic rats, NE concentrations increased after 45 min to a similar level observed in control rats during the first 20 min of hypoglycemia. These results are consistent with the suggestion that local neurons in the VMH respond to hypoglycemia and modify NE activation in the VMH during hypoglycemia. |
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Authors:
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Kelly R Fugo; Marc A Lawson; J Lee Beverly |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2006-08-14 |
Journal Detail:
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Title: Brain research Volume: 1111 ISSN: 0006-8993 ISO Abbreviation: Brain Res. Publication Date: 2006 Sep |
Date Detail:
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Created Date: 2006-09-11 Completed Date: 2006-11-24 Revised Date: 2007-12-03 |
Medline Journal Info:
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Nlm Unique ID: 0045503 Medline TA: Brain Res Country: Netherlands |
Other Details:
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Languages: eng Pagination: 105-10 Citation Subset: IM |
Affiliation:
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Neuroscience Program, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Autonomic Pathways / metabolism* Denervation Down-Regulation / physiology Excitatory Amino Acid Agonists / pharmacology Hypoglycemia / chemically induced, metabolism*, physiopathology Ibotenic Acid / pharmacology Insulin / pharmacology Male Neurons / metabolism* Neurotoxins / pharmacology Norepinephrine / metabolism* Presynaptic Terminals / metabolism, secretion Rats Rats, Sprague-Dawley Rhombencephalon / metabolism, secretion Synaptic Transmission / physiology Time Factors Ventromedial Hypothalamic Nucleus / metabolism* |
| Grant Support | |
ID/Acronym/Agency:
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DK59755/DK/NIDDK NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Excitatory Amino Acid Agonists; 0/Neurotoxins; 11061-68-0/Insulin; 2552-55-8/Ibotenic Acid; 51-41-2/Norepinephrine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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