(+)和(-)一叶萩碱对大鼠海马突触传递功能的影响及其作用机制

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

目的 观察左旋、右旋一叶萩碱对麻醉大鼠海马齿状回基础突触传递功能的影响 ,并进一步研究其作用机制。方法 用在体记录突触传递长时程增强 (LTP)的电生理学方法 ,记录大鼠海马齿状回颗粒细胞层群峰电位(populationspike,PS)。结果 终浓度 2× 10 - 9mol·L- 1 的 (+ ) ,(- )一叶萩碱对基础状态下的PS无影响 ,对HFS诱导的LTP也无增强作用。将终浓度提高至 2× 10 - 8,2× 10 - 7mol·L- 1 时 ,两种构型一叶萩碱对基础PS和HFS诱导的LTP有明显的增强作用 ,GABA能完全拮抗此作用。结论 (+ ) ,(- )一叶萩碱在相同浓度下产生相似的效应 。

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 -1 ), (+),(-) 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.