Kenshi Takechi

Participation of metabotropic glutamate receptors in pentetrazol-induced kindled seizure

Purpose:u2002 The present study was undertaken to clarify the effects of (RS)‐1‐aminoindan‐1,5‐dicarboxylic acid (AIDA), a metabotropic glutamate receptor (mGluR) 1 antagonist, (2R,4R)‐4‐aminopyrrolidine‐2,4‐dicarboxylate ((2R,4R)‐APDC), a mGluR2/3 agonist, and L‐(+)‐2‐amino‐4‐phosphonobutyric acid (L‐AP4), a mGluR4/8 agonist, on pentetrazol‐induced kindled seizures.

Changes of visual evoked potential induced by lateral geniculate nucleus kindling in rats

PURPOSEnThe present study was undertaken to investigate the changes of visual evoked potential (VEP) induced by lateral geniculate nucleus (LGN) kindling in comparison with those induced by amygdala (AMG) and hippocampus (HPC) kindling in rats.nnnMETHODSnUnder pentobarbital anesthesia, the rats were fixed to a stereotaxic apparatus, and stainless steel electrodes were implanted into the LGN, AMG, HPC and the occipital cortex (OCOR). Bipolar stimulation was applied to the LGN, AMG or HPC every day until generalized seizure was obtained. VEP was recorded from the OCOR before the first day of electric stimulation (pre-kindled) and after the development of kindling (post-kindled).nnnRESULTSnAfter the development of LGN kindling, the amplitudes of early VEP components (P(1)-N(1) and N(1)-P(2)) were significantly augmented in comparison with those of pre-kindled rats. In addition, the duration of the photically evoked after-discharge burst (duration of VEP) was significantly prolonged by LGN kindling. On the other hand, in AMG and HPC kindling, no significant changes were observed in VEP between pre-kindled and post-kindled rats.nnnCONCLUSIONSnThe changes of VEP observed in patients with photosensitive epilepsy are also demonstrated in animal study using LGN kindling.

The usefulness of olfactory bulb kindling as a model for evaluation of antiepileptics

Purpose:u2002 The present study was undertaken to clarify the behavioral and electroencephalographic characteristics of olfactory bulb (OB) kindling in rats, in comparison with those of amygdala (AMG) kindling. In addition, the usefulness of OB kindling as a model to evaluate antiepileptics was studied.

Participation of GABA-ergic system in epileptogenic activity induced by teicoplanin in mice

PURPOSEnThe present study was undertaken to clarify the participation of the GABA-ergic system in epileptogenic activity induced by teicoplanin.nnnMETHODSnUnder pentobarbital anesthesia, mice were fixed to a stereotaxic apparatus, and stainless steel electrodes were implanted into the frontal cortex (FCOR), hippocampus (HPC) and amygdala (AMG). Behavioral and electroencephalographic (EEG) changes were observed for 60min following teicoplanin intracerebroventricular (i.c.v.) injection.nnnRESULTSnI.c.v. injection of teicoplanin caused dose-related behavioral and EEG seizures. MK-801 (N-methyl-d-aspartate receptors antagonist) had no significant influence on either behavioral or EEG seizures induced by teicoplanin (500microg, i.c.v.). On the other hand, NNC-711 (GABA transporters inhibitor) dose-dependently antagonized behavioral and EEG seizures induced by teicoplanin (500microg, i.c.v.). The inhibitory effect of NNC-711 (10mg/kg, i.p.) on teicoplanin-induced epileptogenic activity was antagonized by bicuculline (GABA(A) receptor antagonist) but not by TPMPA (GABA(C) receptor antagonist).nnnCONCLUSIONSnIt is reasonable to presume that teicoplanin-induced epileptogenic seizures are closely related with GABA-ergic mechanisms through GABA(A) receptors rather than GABA(C) receptors.