乌拉坦对大鼠海马CA1区锥体神经元自发放电的抑制作用  

Effects and Mechanism of Urethane on Spontaneous Firing of Hippocampal CA1 Pyramidal Neurons in Rats

作　　者：雷霆[1] 阎睿[1] 李雅堂[1] 杨卓[2] 张涛[1] 

机构地区：[1]南开大学生命科学学院,生物活性材料教育部重点实验室,天津300071 [2]南开大学医学院,天津300071

出　　处：《生物化学与生物物理进展》2008年第12期1403-1409,共7页Progress In Biochemistry and Biophysics

基　　金：国家重点基础研究发展计划(973)(2007CB914803);国家自然科学基金(30870827)资助项目~~

摘　　要：为了深入研究麻醉药乌拉坦对大鼠海马CA1锥体神经元自发放电的作用及其机制,分析了10mmol/L乌拉坦对自发放电、电压门控钠通道、电压门控钾通道的作用.从自发放电信号中计算了放电频率、提取了峰峰间隔序列(ISI)并利用样品熵和去趋势波动法对ISI进行了非线性分析.结果表明,乌拉坦不仅抑制了自发放电的频率,而且降低了自发放电ISI序列的复杂度并弱化了其长时程相关性.离子通道研究结果表明,乌拉坦显著地抑制了钠通道电流(INa),对延迟整流钾通道电流(IK)和瞬时外向钾通道电流(IA)虽然也有抑制作用但无统计学意义.由于乌拉坦不影响突触传递,因此它可能通过抑制INa使自发放电的阈值升高而降低放电频率,同时,由于参与的通道数量或活性降低而使得ISI的复杂度下降,长时程相关性弱化.To obtain more information related to the inhibitive effect of anesthetic on spontaneous firing of neurons, several kinds of experimental data were collected before and after applying 10 mmol/L urethane, which included spontaneous firing, sodium current （INa）, delayed rectifier potassium current （IK） and transient outward potassium current （IA） of hippocampal CA1 pyramidal neurons in rats. All of the experiments were performing on hippocampal slices in vitro. Sample entropy （SampEn） and detrended fluctuation analysis （DFA） were employed to measure the complexity and fractal property of spontaneous firing of neurons. It was found that the spontaneous firing rate was significantly decreased, the entropy of ISI sequence was obviously reduced, and the long-range temporal correlations of ISI sequence were weakened after performing 10 mmol/L urethane. Furthermore, INa was significantly inhibited, but IK and IA were not statistically changed for 10 mmol/L urethane. This suggests that the fractal properties and complexity of underlying dynamics of the system have been reduced by urethane. And the reduction of complexity may because of inhibition of INa. The results demonstrate that apparently random fluctuations in neuron spontaneous firing are dictated by a complex deterministic process that imparts ＂long-term＂ memory to the dynamic system.

关 键 词：乌拉坦 自发放电 钠通道 钾通道 复杂度 长时程相关 

分 类 号：Q424[生物学—神经生物学] R338[生物学—生理学]