Changes of cortical epileptic afterdischarges under the influence of convulsant drugs.

Convulsant drugs picrotoxin (0.5 and/or 1 mg/kg, intraperitoneal (i.p.

Effect of a subconvulsant dose of kainic acid on thresholds for phenomena elicited by electrical stimulation of sensorimotor cortex in rats.

Electrical stimulation of sensorimotor cortex was used to study early and late effects of administration of kainic acid in a dose (6 mg/kg i.p.) eliciting only nonconvulsive seizures in rats.

Effects of a subconvulsant dose of kainic acid on afterdischarges elicited by cortical stimulation in rats.

The aim of this study was to test the hypothesis that nonconvulsive seizures elicited by a low dose of kainic acid may induce acute as well as chronic changes in brain function. Cortical epileptic afterdischarges (ADs) characterized by spike-and-wave rhythm and clonic seizures of facial and forelimb muscles were elicited in adult male rats with chronically implanted electrodes. Four stimulations were given in each of four weekly sessions.

Synaptic vesicle size and shape profile in the kindling model of epileptogenesis.

Excitatory synapses were studied in the dentate gyrus ipsilateral to stimulated entorhinal cortex in fully kindled rats 2 weeks after the last (3rd) stage 5 seizure. In previous studies of the same model marked redistribution of synaptic vesicles to a 'strategic position' in the vicinity of the synaptic cleft and a significant enlargement of postsynaptic element were described. In this study the size and shape of synaptic vesicles were evaluated in three zones parallel to the presynaptic membrane of the synaptic cleft.

Motor and electrocorticographic epileptic activity induced by 3-mercaptopropionic acid in immature rats.

The convulsant action of 3-mercaptopropionic acid (3-MPA), a known inhibitor of glutamate decarboxylase activity, was studied in 7-, 12-, 18- and 25-day-old rats and in adult animals. 3-MPA elicited predominantly clonic, minimal seizures as well as generalized tonic-clonic (major) seizures at all developmental stages studied. The CD50 for major seizures did not change during development; CD50 for minimal seizures was significantly lower in 18-day-old rats than in older animals.