【摘要】 目的和方法 :以频率为 1、3或 5Hz,脉冲数为 30 0或 90 0 ,与高频刺激 (HFS)时间间隔是 2 0min或 10 0min的低频刺激 (LFS)作用于大鼠海马脑片 ,分别观察其对CA1区突触传递去长时程增强 (DP)形成的影响。结果 :HFS(10 0Hz,10 0脉冲的串刺激两串 ,串间隔 30s)可诱发突触传递效率的长时程增强 (LTP)。HFS后 2 0min给予 3Hz90 0脉冲的LFS可翻转LTP ,产生DP ,该作用可为NMDA受体阻断剂AP5 (5 0 μmol/L)所阻断 ,1Hz、5Hz、低脉冲数或与HFS时间间隔长的LFS ,其诱发DP的效率减弱。结论 :诱发海马CA1区DP的产生 ,对LFS的参数有较强的依从性。该作用可能是通过激活NMDA受体而实现的更多还原

【Abstract】 Aim and Methods: The parameters of low frequency stimulation (LFS) were altered systematically (frequencies of 1, 3 or 5 Hz; number of pulses of pulses of 300 or 900; and time lag after high frequency stimulation (HFS) of 20 or 100 min) and examined their effects on depotentiation (DP) of long term potentiation (LTP) of synaptic transmission in CA1 neurons in hippocampal slices of rat. Results: LTP could be induced by HFS (two trains of 100 Hz, 100 pulses, separated by 30 s) and be reversed to produce DP by a train of LFS of 900 pulses at 3 Hz given 20 min after HFS. DP induced by LFS could be blocked by NMDA receptor antagonist AP5 (50 μmol/L). And significantly reduced effect was observed for LFS at 1 Hz or 5 Hz, with smaller numbers of pulses or a longer time lag from LFS to HFS. Conclusion: The above results indicate that DP induced in CA1 neurons of rat hippocampal slices is strongly dependent on the parameters of LFS, and the process may be mediated through the NMDA receptor.更多还原