Kainic acid produces depolarization of CA3 pyramidal cells in the vitro hippocampal slice.

Kainic acid (KA) (10(-6)-10(-8) M) reversibly depolarized CA3 pyramidal cells when applied topically to the apical dendritic area of these cells in the hippocampal slice. The magnitude of membrane depolarization and the time to recovery of resting membrane potential were concentration-related. Application of 10(-5) M KA produced complete membrane depolarization which did not recover in baseline levels. Unlike CA3 neurons cells from the CA1 region were unaffected by KA (10(-6)-10(-8) M). However, 10(-5) M KA also proved effective in depolarizing CA1 cells.