Effects of electroconvulsive shock on central GABA-ergic mechanisms.

A single electroconvulsive shock (ECS) has no influence on seizures induced by picrotoxin and bicuculline, although it decreases the level of GABA in the cortex. A repeated ECS (once daily for 7 days) does not change the level of GABA in the cortex, brain stem, and cerebellum, but depresses seizures induced by both compounds. It prolongs the time of their occurrence and decreases their intensity. This effect is stronger in the case of bicuculline. It manifests itself in the increase of the number of animals protected from seizures and decrease of their lethality. Baclofen does not change ECS action on seizures induced by picrotoxin and bicuculline whereas it enhances catalepsy caused by ECS. Bicuculline does not change the time-course of catalepsy. The obtained results suggest that repeated ECS reduces the seizures induced by GABA antagonists probably y increasing GABA-ergic transmission or/and by increasing dopaminergic and serotoninergic transmission which significantly modify the activity of GABA-ergic neurons.