title: Convulsant activity and neurochemical alterations induced by a fraction obtained from fruit Averrhoa carambola (Oxalidaceae: Geraniales).
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.
authors.affiliation: Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, SP, Brazil.
authors.forename: Ruither O G
authors.initials: RO
authors.lastname: Carolino
authors.forename: Renê O
authors.initials: RO
authors.lastname: Beleboni
authors.forename: Andrea B
authors.initials: AB
authors.lastname: Pizzo
authors.forename: Flavio Del
authors.initials: FD
authors.lastname: Vecchio
authors.forename: Norberto
authors.initials: N
authors.lastname: Garcia-Cairasco
authors.forename: Miguel
authors.initials: M
authors.lastname: Moyses-Neto
authors.forename: Wagner F Dos
authors.initials: WF
authors.lastname: Santos
authors.forename: Joaquim
authors.initials: J
authors.lastname: Coutinho-Netto
mesh_terms: 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
chemical_list: D003292:Convulsants; D009498:Neurotoxins; D010936:Plant Extracts; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid