Convulsant activity and neurochemical alterations induced by a fraction obtained from fruit Averrhoa carambola (Oxalidaceae: Geraniales).
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.
Carolino
Ruither O G
RO
Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, SP, Brazil.
Beleboni
Renê O
RO
Pizzo
Andrea B
AB
Vecchio
Flavio Del
FD
Garcia-Cairasco
Norberto
N
Moyses-Neto
Miguel
M
Santos
Wagner F Dos
WF
Coutinho-Netto
Joaquim
J
D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D001923:Brain Chemistry / Q000187:drug effects* / Q000502:physiology; D003292:Convulsants / Q000302:isolation & purification / Q000633:toxicity*; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D005638:Fruit / Q000737:chemistry; D018698:Glutamic Acid / Q000378:metabolism; D019684:Magnoliopsida / Q000737:chemistry*; D008297:Male; D051379:Mice; D008970:Molecular Weight; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009498:Neurotoxins / Q000302:isolation & purification / Q000633:toxicity*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D003292:Convulsants; D009498:Neurotoxins; D010936:Plant Extracts; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid