1. For many years it has been discussed whether repeated electroconvulsive shock (ECS) may induce a lasting epileptogenic effect on the brain (i.e. a kindling effect). In the present study the authors investigated whether weekly ECS do exert such an effect. 2. Bipolar electrodes were implanted in amygdala of 32 rats. Following a two to three week recovery period the rats were randomly allocated to two groups. One group received 12 weekly ECS, the other 12 weekly sham-ECS. 3. Three months after the last ECS/sham-ECS, kindling was initiated. Daily stimulation, eliciting an EEG-afterdischarge was given to all the rats. The animals received a total of 15 stimulations. 4. ECS-pretreated animals did not kindle faster than the sham-group. The two groups reached stage 4 (clonic rearing) after 5.8 (ECS-group) and 5.7 (sham-group) stimulations, respectively. 5. The authors did not find a facilitated development of kindling following ECS, instead they observed a slight, yet statistically significant inhibition of the development of the maximally generalized kindling-seizure--the stage 5 seizure--in the ECS-group. 6.
In conclusion: The present study did not show a kindling effect of weekly ECS suggesting that kindling requires more than repeated elicitation of after-discharge.