Antiepileptic effect of acylpolyaminetoxin JSTX-3 on rat hippocampal CA1 neurons in vitro.
The Joro spider toxin (JSTX-3), derived from Nephila clavata, has been found to block glutamate excitatory activity. Epilepsy has been studied in vitro, mostly on rat hippocampus, through brain slices techniques. The aim of this study is to verify the effect of the JSTX-3 on the epileptiform activity induced by magnesium-free medium in rat CA1 hippocampal neurons. Experiments were performed on hippocampus slices of control and pilocarpine-treated Wistar rats, prepared and maintained in vitro. Epileptiform activity was induced through omission of magnesium from the artificial cerebrospinal fluid (0-Mg2+ ACSF) superfusate and iontophoretic application of N-methyl-D-aspartate (NMDA). Intracellular recordings were obtained from CA1 pyramidal neurons both of control and epileptic rats. Passive membrane properties were analyzed before and after perfusion with the 0-Mg2+ ACSF and the application of toxin JSTX-3. During the ictal-like activity, the toxin JSTX-3 was applied by pressure ejection, abolishing this activity. This effect was completely reversed during the washout period when the slices were formerly perfused with artificial cerebrospinal fluid (ACSF) and again with 0-Mg2+ ACSF. Our results suggest that the toxin JSTX-3 is a potent blocker of induced epileptiform activity.
Salamoni
Simone Denise
SD
Laboratório de Neurociências, Instituto de Pesquisas Biomédicas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brasil.
Costa da Costa
Jaderson
J
Palma
Mário Sérgio
MS
Konno
Katsuhiro
K
Nihei
Ken-Ichi
K
Tavares
Andréa Alencar
AA
de Abreu
Daniela Souza
DS
Venturin
Gianina Teribele
GT
de Borba Cunha
Fernanda
F
de Oliveira
Raquel Mattos
RM
Breda
Ricardo Vaz
RV
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D000927:Anticonvulsants / Q000494:pharmacology* / Q000627:therapeutic use; D004558:Electric Stimulation; D004827:Epilepsy / Q000139:chemically induced / Q000188:drug therapy / Q000503:physiopathology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D006571:Heterocyclic Compounds / Q000494:pharmacology* / Q000627:therapeutic use; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology; D019832:N-Methylscopolamine; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods; D011073:Polyamines / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar
D000927:Anticonvulsants; D018690:Excitatory Amino Acid Agonists; D006571:Heterocyclic Compounds; C426070:JSTX-3; D011073:Polyamines; D016202:N-Methylaspartate; D008274:Magnesium; D019832:N-Methylscopolamine