Alaproclate increases the excitability of hippocampal CA1 pyramidal cells and blocks the slow after-hyperpolarization

Effects of alaproclate, an antidepressive substance and 5-HT uptake blocker, was studied using intracellular and extracellular recording techniques. Possible effects on the excitability of CA1 pyramidal cells in slices from rat hippocampus were explored. Alaproclate increased the probability of firing to an orthodromic input, increased the membrane resistance and prolonged the action potential. Increased excitability was also observed in extracellular recording experiments. It is suggested that these effects are due to depression of potassium channels in the membrane.