Excitatory action of BAYK8644 on hippocampal pyramidal neurones of the guinea pig in vitro.

BAYK8944, a calcium 'agonist' caused a slow depolarization of a proportion of CA1 hippocampal pyramidal cells and increased their input resistance. In voltage-clamped CA1 neurones BAYK8644 caused a decrease in depolarization-activated outward current. Reduction of depolarization-activated outward current was also produced by the Ca ionophore A23187. It is proposed that BAYK8644 and A23187 may cause suppression of outward current secondary to a prolonged increase in cytosolic Ca activity.