EFFECT AND MECHANISM OF SECURININE ON SYNAPTIC TRANSMISSION IN THE DENTATE GYRUS OF ANESTHETIZED RATS

AIM To study the effects of (+) and (-) securinine on the basic synaptic transmission and long-term potentiation (LTP) induced by high-frequency stimulation in the dentate gyrus of anesthetized rats and its possible mechanism. METHODS The population spike (PS) was recorded by electrophysiological techniques. RESULTS The results showed that at the concentration of 2×10^-9 mol·L^-1 , (+),(-) securinine showed no effect on either the basal PS or LTP. At high concentrations (2×10^-8, 2×10^-7 mol·L^-7), (+),(-) securinine not only potentiated the basal PS but also enhanced the magnitude of LTP. (+),(-) Securinine showed similar effects; and the effects were completely inhibited by the inhibitory amino acid GABA. CONCLUSION These results suggest that the effects of (+),(-) securinine on induction and maintenance of LTP may be related to its blockade of GABA receptor.