BLOCKADE OF GABA-B RECEPTORS ACCELERATES AMYGDALA KINDLING DEVELOPMENT

The aim of this study was to investigate the putative role of GABA(B) receptors in the development of amygdala kindling in rats. The effects of the GABA(B) blocker CGP 35348 and the GABA(B) agonist baclofen on the progressive development of behavioural seizure symptoms (stages 1-5 classified by Racine) and duration of after-discharges (AD) were studied. CGP 35348 at a dose of 300 mg/kg i.p, which blocks central GABA(B) receptors, moderately but consistently accelerated the development of behavioural seizure symptoms. CGP 35348 had no marked effect on the duration of ADs corresponding to the different seizure stages. L-baclofen (6 mg/kg i.p.) had a dual effect on kindling development. It retarded the development of the behavioural symptoms, but increased the duration of AD. In conclusion, the results suggest that synaptically-released GABA activated GABA(B) receptors and thereby exerted a depressant effect on kindling development.