中文摘要：

为了观察新型静脉全麻药异丙酚对下丘脑视上核（supraoptic nucleus,SON）神经元的作用,并分析其可能的离子机制,本研究应用细胞内记录技术,观察异丙酚灌流对成年雄性Sprague Dawley（SD）大鼠下丘脑冠状切片SON神经元膜电学性质和动作电位的影响。结果显示,0.1mmol/L异丙酚使SON神经元静息电位显著降低（P〈0.01）,而0.3和1.0mmol/L异丙酚显著缩短膜时间常数、减小斜率电阻（P〈0.01）。在超极化电流脉冲幅值大于0.5nA时,部分（11/18）SON神经元可表现出超极化激活的阳离子通道（hyperpolarization-activated cation channel,Ih通道）所致的异常整流现象,而异丙酚能可逆地取消该异常整流现象。0.1mmol/L异丙酚可显著提高SON神经元阈电位水平（P〈0.01）,显著降低最大上升斜率（Max L.slope）（P〈0.05）,而0.3和1.0mmol/L异丙酚可完全取消部分（分别为1/18和12/17）SON神经元的动作电位。对于未被异丙酚完全取消动作电位的SON神经元,0.3mmol/L异丙酚可显著降低锋电位的幅度（P〈0.05）。0.3～1.0mmol/L异丙酚可显著抑制0.1～0.7nA去极化电流时的神经元放电频率,使电流刺激强度-放电频率曲线右移和压低。以上结果提示,异丙酚可降低下丘脑SON神经元的兴奋性,其机制可能涉及对Ih通道和Na＋通道的抑制。

英文摘要：

To investigate the effects of novel intravenous general anesthetic propofol on membrane electrophysiological characteristics and action potential （AP） of the supraoptic nucleus （SON） neurons and possible ionic mechanisms,intracellular recordings were con-ducted in SON neurons from the coronal hypothalamic slice preparation of adult male Sprague Dawley （SD） rats.The results showed that bath application of 0.1 mmol/L propofol induced a significant decline in resting potential （P〈0.01）,and higher concentrations of propofol （0.3 and 1.0 mmol/L） decreased time constant and slope resistance of cell membrane （P〈0.01）.Under the hyperpolarizing current pulses exceeding 0.5 nA,an anomalous rectification was induced by hyperpolarization-activated cation channel （Ih channel） in 11 out of 18 tested SON neurons.Bath of propofol reversibly decreased the anomalous rectification.Moreover,0.1 mmol/L propofol elevated threshold level （P〈0.01） and decreased Max L.slope （P〈0.05） of the spike potential in SON neurons.Interestingly,0.3 and 1.0 mmol/L propofol nullified APs in 6% （1/18） and 71% （12/17） tested SON neurons,respectively.In the SON neurons where APs were not nullified,propofol （0.3 mmol/L） decreased the amplitude of spike potential （P〈0.05）.The higher concentrations of propofol （0.3 and 1.0 mmol/L） decreased firing frequencies evoked by depolarizing current pulses （0.1-0.7 nA）,and shifted the current intensity-firing frequency relation curves downward and to the right.These results suggest that propofol decreases the excitability of SON neu-rons by inhibiting Ih and sodium channels.