The electrical responses of 25 cells suggested to be hippocampal inhibitory interneurons to stimulation of two afferent fibre systems originated in contralateral hippocampus were investigated in nonanesthetized curarized rabbits. It is stated that the neurons under study have not only high-effective excitatory input but also a weak inhibitory one. The background and evoked activities of the neurons were under predominating influence of the excitatory input which plays a determining role in their behaviour.