Postictal seizure inhibition in amygdaloid-kindled cats.

A recycling trial consisting of six amygdaloid stimuli at 60-min intervals was applied to evaluate postictal seizure inhibition (PSI). Cats kindled unilaterally and bilaterally from the amygdala were used. The results obtained may be summarized as follows: (1) kindled generalized convulsions resulted in three consecutive postictal stages before recovery from postictal behavioral depression; (2) in bilaterally kindled cats, PSI lasted for 3-4 h, which was longer than the postictal behavioral depression; (3) no correlation was found between interictal spike frequency and decreased susceptibility to convulsion during PSI; (4) the duration of PSI was prolonged significantly after secondary site amygdaloid kindling; and (5) such changes were observed greater than 2 weeks after the last secondary site stimulation. It is suggested that the intensity of PSI is altered by the establishment of secondary epileptogenesis in the contralateral hemisphere, which exerts a long-lasting seizure inhibitory effect on the primary epileptogenic focus.