槐定碱对大鼠海马齿状回突触传递的影响

Effects of Sophoridine on Synaptic Transmission in the Dentate Gyrus of Anesthetized Rats

目的观察槐定碱对麻醉大鼠海马齿状回突触传递活动的影响。方法采用急性埋藏电极记录麻醉大鼠海马齿状回诱发电位的方法,以群峰电位(PS)幅度和群体兴奋性突触后电位(pEPSP)斜率为观察指标,观察腹腔注射槐定碱(3.0、6.0、12.0 mg.kg-1)对基础突触传递和高频刺激诱导长时程增强(LTP)诱导的影响。结果槐定碱能够明显增大基础突触传递的诱发电位PS幅值且不呈剂量依赖关系,但对pEPSP slope没有影响;能够促进条件刺激引发的pEPSP斜率LTP现象且不呈剂量依赖关系,但对PS幅度没有影响。结论槐定碱对基础突触传递过程中海马齿状回(DG)颗粒细胞的兴奋性有促进作用,但对大鼠内侧穿行通路(MPP)-DG通路形成的突触联系过程没有影响;对高频刺激诱发LTP后突触后颗粒细胞的兴奋性没有影响,但对高频刺激诱发LTP后的突触传递过程有促进作用。

Objective To investigate the effects of sophoridine on synaptic transmission in the dentate gyrus of anesthetized rats.Methods Perforant path evoked field potentials were recorded in the dentate gyrus by acutely implanted electrodes.Two parameters,the slope of population excitatory postsynaptic potential（pEPSP slope） and the amplitude of population spike（PS amplitude）,were employed to evaluate the effects of drug.LTP was induced by high-frequency stimulation（60 pulses at 60 Hz） 30 min after intraperitoneal administration of sophoridine（3,6,or 12mg·kg^-1）.Results Sophoridine could significantly increase the basal synaptic transmission in PS amplitude in a non-dose-dependent manner after intraperitoneal administration,but had no significant effect in pEPSP slope.On the other hand,Sophoridine could increase pEPSP slope after LTP induction in a non-dose-dependent manner,but had no effect in PS amplitude.Conclusion The results suggest that sophoridine can promote the basal synaptic transmission in PS amplitude and the induction of LTP in pEPSP slope.