Abstract
We obtained a neurotoxic fraction (AcTx) from star fruit (Averrhoa carambola) and studied its effects on GABAergic and glutamatergic transmission systems. AcTx had no effect on GABA/glutamate uptake or release, or on glutamate binding. However, it specifically inhibited GABA binding in a concentration-dependent manner (IC(50)=0.89muM). Video-electroencephalogram recordings demonstrated that following cortical administration of AcTx, animals showed behavioral changes, including tonic-clonic seizures, evolving into status epilepticus, accompanied by cortical epileptiform activity. Chemical characterization of AcTx showed that this compound is a nonproteic molecule with a molecular weight less than 500, differing from oxalic acid. This neurotoxic fraction of star fruit may be considered a new tool for neurochemical and neuroethological research.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Binding, Competitive
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Brain / drug effects*
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Brain / metabolism
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Brain / physiopathology
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Brain Chemistry / drug effects*
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Brain Chemistry / physiology
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Convulsants / isolation & purification
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Convulsants / toxicity*
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Epilepsy / chemically induced
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Epilepsy / metabolism
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Epilepsy / physiopathology
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Fruit / chemistry
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Glutamic Acid / metabolism
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Magnoliopsida / chemistry*
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Male
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Mice
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Molecular Weight
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Neurons / drug effects
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Neurons / metabolism
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Neurotoxins / isolation & purification
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Neurotoxins / toxicity*
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Plant Extracts / chemistry
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Plant Extracts / isolation & purification
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Plant Extracts / toxicity*
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Presynaptic Terminals / drug effects
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Presynaptic Terminals / metabolism
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Radioligand Assay
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Rats
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Rats, Wistar
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology
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gamma-Aminobutyric Acid / metabolism
Substances
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Convulsants
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Neurotoxins
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Plant Extracts
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Glutamic Acid
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gamma-Aminobutyric Acid