641LEVETIRACETAM ENHANCES α7 ACH RECEPTOR RESPONSES BY INDIRECTLY INTERACTING PROTEIN KINASE A AND PROTEIN KINASE CLevetiracetam is clinically used as an antiepileptic drug with the mechanism distinct from conventional ones. The present study investigated the new actions of levetiracetam. In the Xenopus oocyte expression systems, levetiracetam potentiated currents through α7 ACh receptor channels, and the potentiation was abrogated by the protein kinase A (PKA) inhibitor H-89 or the protein kinase C (PKC) inhibitor GF109203X. Levetiracetam did not activate PKA or PKC both in the cell-free systems or PC-12 cells. Levetiracetam facilitated hippocampal synaptic transmission to 120% of basal levels. Taken together, the results of the present study show that levetiracetam potentiates α7 ACh receptor responses by indirectly interacting with PKA and PKC, to facilitate hippocampal synaptic transmission. This may extend our understanding of the levetiracetam signaling.tomoyuki@hyo-med.ac.jpResearch672015Levetiracetam,α7 ACh receptor,Protein kinase A,Protein kinase C,Hippocampal synaptic transmissionShun Tsudaka,Takeshi Kanno,Tomoyuki NishizakiDivision of Bioinformation, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan.,Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan.,Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, Nishinomiya, Japan.