大鼠海马兴奋性突触传递的表观受体动力学分析及其应用

Analysis of the apparent receptor kinetics in excitatory synaptic transmission in rat hippocampus

目的:观察大鼠离体海马脑片CA1区锥体神经元兴奋性突触后电位(EPSP)的刺激强度依赖性及表观受体动力学性质。方法:应用成年大鼠海马脑片CA1区锥体神经元细胞内记录技术,观察不同强度电刺激Schaffer侧支诱发的EPSP的变化,并分析其表观受体动力学特性,以及在LTP中的变化。结果:(1)电刺激Schaffer侧支诱发EPSP的幅度与刺激强度呈正相关(r=0.9251,P<0.01),表观解离速率常数K2和表观平衡解离常数KT均随刺激强度增强而降低,对应的相关系数r=-0.9725和-0.9483(P均<0.01)。(2)给予Schaffer侧支的强直刺激在6个测试神经元中的3个细胞诱发出LTP,对LTP过程中的EPSP表观受体动力学分析显示强直刺激后10 min时K2和KT值减小(P<0.01)。结论:大鼠海马CA1锥体神经元EPSP的表观受体动力学参数具有刺激强度依赖性,表观受体动力学分析方法亦可用于海马LTP的分析。

Objective：To observe the stimulus intensity-dependent and the apparent receptor kinetics properties of excitatory postsynaptic potential （EPSP） in hippocampal CA1 pyramidal neurons in the slice preparation of adult rats by in vitro technique.Methods：Hippocampal CA1 neurons were prepared from the slices of adult rats,and intracellular recording technique was used to observe the changes of EPSPs evoked by Schaffer collateral electrical stimulation at different intensities,and the receptor kinetics properties of EPSPs and the changes of receptor kinetics in long-term potentiation（LTP） were analyzed with apparent receptor kinetics technique.Results：①The amplitude of EPSPs evoked by Schaffer collateral stimulation was increased with higher stimulus intensity （r=0.9251,P〈 0.01）,while the correlation coefficient （r） between apparent dissociation rate constant （K2） or apparent equilibrium dissociation constant （KT） of EPSPs and stimulus intensity was decreased,with corresponding correlation coefficient of-0.9725 or-0.9483（P〈0.01）;②The LTP was evoked by tetanic stimulation of Schaffer collaterals in 3 of the 6 tested neurons,and the apparent receptor kinetics of EPSPs during LTP showed decreased K2 and KT at 10 min following tetanic stimulation（P〈0.01）.Conclusion：The apparent receptor kinetics parameters K2 and KT of EPSPs in hippocampal CA1 pyramidal neurons are stimulus intensity-dependent,and the apparent receptor kinetics analysis may be used for measurement of LTP in hippocampus either.