丙泊酚对大鼠海马CA1区长时程增强的影响

目的：研究丙泊酚对大鼠海马CA1区长时程增强（LTP）表达的影响,并探讨其机制。方法：63只戊巴比妥钠麻醉大鼠分多组,分别观察腹腔注射丙泊酚20mg/kg对海马CA1区树突层兴奋性突触后膜电位（EPSP）、LTP表达的影响以及与D-2-氨基-5-磷酸戊酸（APV）和6-氰基-7-硝基喹啉-2,3-二酮（CNQX）合用时对LTP表达的影响。结果：各组基础EPSP幅值稳定;高频刺激（HFS）前应用丙泊酚引出的LTP与对照组相当（P〉0.05）,HFS后LTP幅值明显低于对照组（P〈0.01）;丙泊酚合用APV后不能引出LTP,合用CNQX后幅值一过性升高后,迅速下降并低于基线（P〈0.05）。结论：丙泊酚20mg/kg腹腔注射不影响戊巴比妥钠麻醉大鼠海马CA1区N-甲基-D-门冬氨酸（NMDA）受体依赖型LTP诱导,但可影响其维持;其机制与阻滞α-氨基-3-羟基-5-甲基恶唑-4-丙酸（AMPA）受体有关,与NMDA受体功能状态无关。

Effects of propofol on long-term potentiation of CA1 area in rat hippocampus in vivo

AIM: To study the effects of propofol on long-term potentiation (LTP) in the CA1 area of rat hippocampus in vivo and to elucidate the possible underlying mechanisms. METHODS: 63 pentobarbitone-anaesthetized rats were used to investigate the effects of propofol (20 mg/kg, i.p.) alone and with NMDA or AMPA receptor antagonists (APV or CNQX) on excitatory post-synaptic potential (EPSP) and LTP expression of the CA1 stratum radiatum of the rat hippocampus by using stereotaxic technology and extracellular recording. RESULTS: Baseline EPSP amplitudes of all groups were stable. During treatment with propofol before high frequency stimulation (HFS), LTP amplitude was the same as that of control (P>0.05), whereas when given after HFS,propofol significantly lowered the amplitude of LTP compared with control (P<0.01). On the other hand, LTP could not be induced after treatment of propofol with APV, however, the amplitude of LTP increased transiently and decreased to baseline rapidly after treatment with propofol and CNQX (P<0.05). CONCLUSION: Propofol did not affect the induction of LTP which is dependent on NMDA receptors in the CA1 area of the rat hippocampus but propofol did inhibit the LTP maintenance, which may be attributed to blockade of AMPA receptors but not to NMDA receptors.