Dietary protein restriction causes modification in aluminum-induced alteration in glutamate and GABA system of rat brain

Prasunpriya Nayak,Ajay K Chatterjee

doi:10.1186/1471-2202-4-4

Prasunpriya Nayak, Ajay K Chatterjee

Open Access

https://doi.org/10.1186/1471-2202-4-4

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Abstract

BackgroundAlteration of glutamate and γ-aminobutyrate system have been reported to be associated with neurodegenerative disorders and have been postulated to be involved in aluminum-induced neurotoxicity as well. Aluminum, an well known and commonly exposed neurotoxin, was found to alter glutamate and γ-aminobutyrate levels as well as activities of associated enzymes with regional specificity. Protein malnutrition also reported to alter glutamate level and some of its metabolic enzymes. Thus the region-wise study of levels of brain glutamate and γ-aminobutyrate system in protein adequacy and inadequacy may be worthwhile to understand the mechanism of aluminum-induced neurotoxicity.ResultsProtein restriction does not have any significant impact on regional aluminum and γ-aminobutyrate contents of rat brain. Significant interaction of dietary protein restriction and aluminum intoxication to alter regional brain glutamate level was observed in the tested brain regions except cerebellum. Alteration in glutamate α-decarboxylase and γ-aminobutyrate transaminase activities were found to be significantly influenced by interaction of aluminum intoxication and dietary protein restriction in all the tested brain regions. In case of regional brain succinic semialdehyde content, this interaction was significant only in cerebrum and thalamic area.ConclusionThe alterations of regional brain glutamate and γ-aminobutyrate levels by aluminum are region specific as well as dependent on dietary protein intake. The impact of aluminum exposure on the metabolism of these amino acid neurotransmitters are also influenced by dietary protein level. Thus, modification of dietary protein level or manipulation of the brain amino acid homeostasis by any other means may be an useful tool to find out a path to restrict amino acid neurotransmitter alterations in aluminum-associated neurodisorders.

Highlights

Alteration of glutamate and γ-aminobutyrate system have been reported to be associated with neurodegenerative disorders and have been postulated to be involved in aluminuminduced neurotoxicity as well
Body weight and food intake of animals Changes in the difference between body weights of aluminum treated (BWT) and pair-fed control (BWC) animals during the period of treatment have been depicted in figure 1
Following aluminum treatment of rats fed on an adequate protein diet, the increases in the aluminum contents of the cerebrum, thalamic area, midbrain-hippocampal region and cerebellum were 52%, 69%, 100% and 50% respectively, while on an inadequate protein diet such increases in the respective brain regions were 85%, 80%, 89% and 73%

Summary

Introduction

Alteration of glutamate and γ-aminobutyrate system have been reported to be associated with neurodegenerative disorders and have been postulated to be involved in aluminuminduced neurotoxicity as well. An well known and commonly exposed neurotoxin, was found to alter glutamate and γ-aminobutyrate levels as well as activities of associated enzymes with regional specificity. Protein malnutrition reported to alter glutamate level and some of its metabolic enzymes. The region-wise study of levels of brain glutamate and γ-aminobutyrate system in protein adequacy and inadequacy may be worthwhile to understand the mechanism of aluminum-induced neurotoxicity. Augmented brain glutamate level is observed in protein malnutrition [9] as well as in aluminum intoxication [10]. Alteration in brain glutamate metabolism may play significant role in aluminum-induced higher function disorders of brain

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