Repetitive seizures cause an increase in paired-pulse inhibition in the dentate gyrus.

A paired-pulse stimulus protocol was used to measure angular bundle to dentate gyrus paired-pulse inhibition in rats before and after the occurrence of 36 or 72 seizures elicited from the contralateral CA3 region. The seizures showed progressive lengthening. There was a moderate increase in paired-pulse depression 1 h after 36 seizures and a further increase after 72 seizures. These data demonstrate that the same experimental protocol which produced a decrease in paired-pulse inhibition in the CA1 region caused the opposite effect in the dentate gyrus.