Document Detail

Insulin affects synaptosomal GABA and glutamate transport under oxidative stress conditions.
MedLine Citation:
PMID:  12788509     Owner:  NLM     Status:  MEDLINE    
In this study, we investigated the in vitro effect of exogenously administered insulin on the susceptibility to oxidative stress and on the accumulation of the amino acid neurotransmitters gamma-aminobutyric acid (GABA) and glutamate in a synaptosomal fraction isolated from male Wistar rat brain cortex. Insulin (1 microM) did not affect synaptosomal lipid peroxidation induced by the oxidant pair ascorbate/Fe(2+), although under these conditions an increase in thiobarbituric acid reactive substances (TBARS) levels was observed. Under control conditions, the presence of insulin did not change the uptake of [3H]GABA or [3H]glutamate. In contrast, under oxidizing conditions, we observed a 1.8- and a 2.2-fold decrease in [3H]GABA and [3H]glutamate accumulation, respectively, and insulin reverted the lower levels of both [3H]GABA and [3H]glutamate accumulation (to 86.74+/-6.26 and 67.01+/-6.65% of control, respectively). Insulin also increased the extrasynaptosomal levels of GABA and glutamate, determined both in control and oxidizing conditions. From this study, we can conclude that insulin is a modulator of amino acid neurotransmitter transport, either directly, as seems to occur under normal conditions, or via the decrease in ATP levels and the subsequent reversion of the amino acid transporters, as seems to occur under oxidative stress conditions. The modulation of both GABA and glutamate transport might be implicated in the neuroprotective role of insulin.
Ana Isabel Duarte; Maria Sancha Santos; Raquel Seiça; Catarina Resende de Oliveira
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Brain research     Volume:  977     ISSN:  0006-8993     ISO Abbreviation:  Brain Res.     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-06-05     Completed Date:  2003-08-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0045503     Medline TA:  Brain Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  23-30     Citation Subset:  IM    
Department of Zoology, Center for Neuroscience of Coimbra, University of Coimbra, 3004-517 Coimbra, Portugal.
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MeSH Terms
Ascorbic Acid / toxicity
Biological Transport / drug effects
Brain / drug effects,  metabolism
Chromatography, High Pressure Liquid / methods
Glutamic Acid / metabolism*
Hypoglycemic Agents / pharmacology*
Insulin / pharmacology*
Iron / toxicity
Lipid Peroxidation / drug effects
Membrane Potentials / drug effects
Oxidative Stress / drug effects*
Rats, Wistar
Synaptosomes / drug effects*,  metabolism
Tritium / metabolism
gamma-Aminobutyric Acid / metabolism*
Reg. No./Substance:
0/Hypoglycemic Agents; 10028-17-8/Tritium; 11061-68-0/Insulin; 50-81-7/Ascorbic Acid; 56-12-2/gamma-Aminobutyric Acid; 56-86-0/Glutamic Acid; 7439-89-6/Iron

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

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