We demonstrated that only membrane-associated protein kinase C (PKC) activity increased in the bilateral hippocampus (HIPP) up to 4 weeks and in the amygdala/pyriform cortex (AM/PC) at 4 weeks after the last kindled seizure. The enhancement of the membrane-associated PKC activity exceeds the increase in the protein concentration, which was observed in part. The overwhelming increase in the PKC activity should be of significance in the long-term maintenance of the kindling phenomenon.