Background Increasing age was shown to decrease the requirements for propfol.However,the mechanisms of ageing-induced potentiation of anesthetic actions have not been clearly explored.The aim of this study is to compa...Background Increasing age was shown to decrease the requirements for propfol.However,the mechanisms of ageing-induced potentiation of anesthetic actions have not been clearly explored.The aim of this study is to compare the effects of propofol on the field excitatory postsynaptic potentials （fEPSPs） in hippocampal slices of young and aging mice.Methods Brain slices were prepared from C57BL6 male young （2 months） and aging （＞12 months） mice.The dendritic field excitatory postsynaptic potential was recorded from the CA1 stratum radiatum using patch clamp electrophysiological methods.A bipolar concentric stimulating electrode was placed along the Schaffer collateral for othodromic stimulation.The effects of clinically-relevant concentrations of propofol were studied in the young and ageing mouse tissues.Results Propofol application increased the orthodromically evoked fEPSP produced in slices taken from young and older animals.A striking feature in the I/O relationship was the decreased enhancement of the fEPSPs by propofol in slices from older mice.A clinically relevant concentration of propofol,10 μmol/L,showed more significant enhancement in amplitude and area under the curve （AUC） of fEPSP in young compared to tissues from older mice （amplitude：young （24.9±3.4）％,old （4.6±1.6）％; AUC young （30.6±5.4）％,old （2.1±1.7）％）.There was no statistically significant difference between the paired-pulse facilitation （PPF） ratios calculated for the responses obtained in tissues from young mice.In slices from older mice,in the presence of 10 μmol/L propofol,PPF was decreased and returned to baseline after washout （baseline 1.21±0.01,propofol：1.16±0.01）.Bicuculline （15 μmol/L） blocked the enhancement of propofol on fEPSP in tissues from young and old mice.Conclusion The fEPSP of slices from aging mice demonstrates diminished sensitivity to the enhancing actions of propofol.展开更多
It has been recognized that substance P (SP) and 5-hydroxytryptamine (5-HT) maybe the transmitters mediating non-cholinergic late slow excitatory postsynaptic potential(LS-EPSP) in the neurons of guinea pig inferior m...It has been recognized that substance P (SP) and 5-hydroxytryptamine (5-HT) maybe the transmitters mediating non-cholinergic late slow excitatory postsynaptic potential(LS-EPSP) in the neurons of guinea pig inferior mesenteric ganglion (IMG). The展开更多
目的观察异丙酚对小鼠鼠海马锥体神经元膜特性和突触后电流的影响。方法用冰冻切片的方法将C57小鼠海马半脑切成300μm厚度。运用全细胞膜片钳技术记录海马锥体神经元在异丙酚作用前后动作电位反应、I-V曲线及突触后电流反应后变化情况...目的观察异丙酚对小鼠鼠海马锥体神经元膜特性和突触后电流的影响。方法用冰冻切片的方法将C57小鼠海马半脑切成300μm厚度。运用全细胞膜片钳技术记录海马锥体神经元在异丙酚作用前后动作电位反应、I-V曲线及突触后电流反应后变化情况。结果异丙酚明显减少不同刺激强度下胞体动作电位产生的个数,加入异丙酚后使锥体细胞动作电位发放个数由5±3个降至2±1个(P<0.01),而对动作电位幅度无显著影响。异丙酚可改变海马锥体神经元对兴奋性电压刺激的I-V曲线平台期反应,使最大电流幅度由1647.63±124.02 p A增加至2955.08±119.10 p A(P<0.01)。异丙酚可降低锥体神经元突触后电流,加入异丙酚前为146.5±25.89 p A,加入异丙酚后为72.8±18.71 p A(P<0.01),20 min洗脱异丙酚后电流幅度恢复至132.1±30.2 p A(P<0.01)。结论异丙酚可降低海马锥体神经元动作电位发放数,改变I-V曲线兴奋性平台期反应和可逆地降低神经元突触后电流反应。展开更多
文摘Background Increasing age was shown to decrease the requirements for propfol.However,the mechanisms of ageing-induced potentiation of anesthetic actions have not been clearly explored.The aim of this study is to compare the effects of propofol on the field excitatory postsynaptic potentials （fEPSPs） in hippocampal slices of young and aging mice.Methods Brain slices were prepared from C57BL6 male young （2 months） and aging （＞12 months） mice.The dendritic field excitatory postsynaptic potential was recorded from the CA1 stratum radiatum using patch clamp electrophysiological methods.A bipolar concentric stimulating electrode was placed along the Schaffer collateral for othodromic stimulation.The effects of clinically-relevant concentrations of propofol were studied in the young and ageing mouse tissues.Results Propofol application increased the orthodromically evoked fEPSP produced in slices taken from young and older animals.A striking feature in the I/O relationship was the decreased enhancement of the fEPSPs by propofol in slices from older mice.A clinically relevant concentration of propofol,10 μmol/L,showed more significant enhancement in amplitude and area under the curve （AUC） of fEPSP in young compared to tissues from older mice （amplitude：young （24.9±3.4）％,old （4.6±1.6）％; AUC young （30.6±5.4）％,old （2.1±1.7）％）.There was no statistically significant difference between the paired-pulse facilitation （PPF） ratios calculated for the responses obtained in tissues from young mice.In slices from older mice,in the presence of 10 μmol/L propofol,PPF was decreased and returned to baseline after washout （baseline 1.21±0.01,propofol：1.16±0.01）.Bicuculline （15 μmol/L） blocked the enhancement of propofol on fEPSP in tissues from young and old mice.Conclusion The fEPSP of slices from aging mice demonstrates diminished sensitivity to the enhancing actions of propofol.
文摘It has been recognized that substance P (SP) and 5-hydroxytryptamine (5-HT) maybe the transmitters mediating non-cholinergic late slow excitatory postsynaptic potential(LS-EPSP) in the neurons of guinea pig inferior mesenteric ganglion (IMG). The
文摘目的观察异丙酚对小鼠鼠海马锥体神经元膜特性和突触后电流的影响。方法用冰冻切片的方法将C57小鼠海马半脑切成300μm厚度。运用全细胞膜片钳技术记录海马锥体神经元在异丙酚作用前后动作电位反应、I-V曲线及突触后电流反应后变化情况。结果异丙酚明显减少不同刺激强度下胞体动作电位产生的个数,加入异丙酚后使锥体细胞动作电位发放个数由5±3个降至2±1个(P<0.01),而对动作电位幅度无显著影响。异丙酚可改变海马锥体神经元对兴奋性电压刺激的I-V曲线平台期反应,使最大电流幅度由1647.63±124.02 p A增加至2955.08±119.10 p A(P<0.01)。异丙酚可降低锥体神经元突触后电流,加入异丙酚前为146.5±25.89 p A,加入异丙酚后为72.8±18.71 p A(P<0.01),20 min洗脱异丙酚后电流幅度恢复至132.1±30.2 p A(P<0.01)。结论异丙酚可降低海马锥体神经元动作电位发放数,改变I-V曲线兴奋性平台期反应和可逆地降低神经元突触后电流反应。
