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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。
In order to observe the effect of propofol, a new intravenous general anesthesia, on the hypothalamic supraoptic nucleus (SON) neurons and to analyze its possible mechanism, we used intracellular recording technique to observe the effect of propofol perfusion on adult male Effect of hypothalamic coronal slice SON neurons on the membrane electrical properties and action potentials in Sprague Dawley rats. The results showed that 0.1 mmol / L propofol significantly decreased the resting potential of SON neurons (P <0.01), whereas 0.3 and 1.0 mmol / L propofol significantly shortened the membrane time constant and decreased the slope resistance (P <0.01) . In the hyperpolarization current pulse amplitude greater than 0.5nA, part of (11/18) SON neurons can show abnormal rectification caused by hyperpolarization-activated cation channel (Ih channel), and Propofol reversibly reverses this abnormal rectification. 0.1 mmol / L propofol significantly increased the threshold potential of SON neurons (P <0.01) and significantly decreased Max L. slope (P <0.05), while 0.3 and 1.0 mmol / L propofol Completely abrogate the action potentials of SON neurons (1/18 and 12/17, respectively). 0.3 mmol / L propofol significantly reduced the amplitude of the spike (P <0.05) for SON neurons that did not completely remove the action potential of propofol. 0.3 ~ 1.0mmol / L propofol can significantly inhibit the 0.1 ~ 0.7nA depolarization current neuron discharge frequency, so that current stimulation intensity - discharge frequency curve right and down. These results suggest that propofol can reduce the excitability of hypothalamic SON neurons, the mechanism may be involved in the Ih channel and Na + channel inhibition.