Lipoic acid alters amino acid neurotransmitters content in rat hippocampus after pilocarpine-induced seizures.
This study was aimed at investigating the anticonvulsant activity of lipoic acid (LA) against pilocarpine-induced seizures as well as the effects of this metabolic antioxidant on the hippocampal extracellular concentrations of amino acid neurotransmitters glutamate, aspartate, glycine and glutamate and γ-aminobutyric acid (GABA). In vivo microdialysis demonstrated that an intraperitoneal administration of pilocarpine induced a pronounced increment of hippocampal glutamate and aspartate concentrations, whereas no significant change was observed in the levels of glycine or GABA. LA (10, 20 or 30 mg/kg) pretreatment completely blocked pilocarpine-evoked increases in extracellular glutamate and aspartate concentrations. Significant reductions in hippocampal GABA and glycine concentrations were also observed although not as pronounced as those shown by glutamate and aspartate. Based on the finding that LA protected rats against pilocarpine-induced seizures, it could be suggested that the reduction in inhibitory amino acid neurotransmitters levels was comparatively minor and offset by a more pronounced reduction in glutamate and aspartate extracellular concentrations. Therefore, the fact that LA could drastically reduce pilocarpine-induced increases in glutamate and aspartate should account, at least partly, for its anticonvulsant activity observed in pilocarpine-induced seizure in rats.
de Freitas
Rivelilson Mendes
RM
Laboratory of Experimental Research in Biological Sciences of Federal University of Piauí, Piauí, Brazil. rivelilson@pq.cnpq.br
de Oliveira Silva
Fábio
F
Saldanha
Gláucio Barros
GB
Jordán
Joaquín
J
D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology / Q000627:therapeutic use; D001224:Aspartic Acid / Q000134:cerebrospinal fluid; D003956:Dialysis / Q000379:methods; D018846:Excitatory Amino Acids / Q000134:cerebrospinal fluid*; D018698:Glutamic Acid / Q000134:cerebrospinal fluid; D005998:Glycine / Q000134:cerebrospinal fluid; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010862:Pilocarpine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism* / Q000401:mortality / Q000503:physiopathology / Q000517:prevention & control; D013226:Status Epilepticus / Q000139:chemically induced / Q000378:metabolism / Q000401:mortality / Q000503:physiopathology / Q000517:prevention & control; D016019:Survival Analysis; D008063:Thioctic Acid / Q000494:pharmacology* / Q000627:therapeutic use; D005680:gamma-Aminobutyric Acid / Q000134:cerebrospinal fluid
D000927:Anticonvulsants; D018846:Excitatory Amino Acids; D010862:Pilocarpine; D001224:Aspartic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D008063:Thioctic Acid; D005998:Glycine