Kindled seizure-evoked somatostatin release in the hippocampus: inhibitionby MK-801

The aim of this study was to evaluate the contribution of ionotropic glutam ate receptors to kindled seizure-evoked somatostatin release in the hippoca mpus, using a microdialysis approach. Basal and amygdala stimulation-evoked somatostatinlike immunoreactivity (-LI) release was significantly greater in kindled compared to naive rats. In naive rats, neither hippocampal perfu sion with the selective AMPA/kainate receptor antagonist GYKI 52466 nor wit h the selective NMDA receptor antagonist MK-801 affected behavior, EEG, or somatostatin-LI release. In kindled rats, GYKI 52466 was still devoid of an y effect, while MK-801 significantly decreased stimulus-evoked (but not bas al) somatostatin-LI efflux. MK-801 produced identical effects when injected i.p. This study provides the first direct evidence that kindled seizure-ev oked somatostatin release in the hippocampus is partly NMDA receptor depend ent. NeuroReport 11:3209-3212 (C) 2000 Lippincott Williams & Wilkins.