Mason W T
Proc R Soc Lond B Biol Sci. 1983 Jan 22;217(1207):141-61. doi: 10.1098/rspb.1983.0003.
The electrical properties of neurons in the supraoptic nucleus (so.n.) have been studied in the hypothalamic slice preparation by intracellular and extracellular recording techniques, with Lucifer Yellow CH dye injection to mark the recording site as being the so.n. Intracellular recordings from so.n. neurons revealed them to have an average membrane potential of -67 +/- 0.8 mV (mean +/- s.e.m.), membrane resistance of 145 +/- 9 M omega with linear current-voltage relations from 40 mV in the hyperpolarizing direction to the level of spike threshold in the depolarizing direction. Average cell time constant was 14 +/- 2.2 ms. So.n. action potentials ranged in amplitude from 55 to 95 mV, with a mean of 76 +/- 2 mV, and a spike width of 2.6 +/- 0.5 ms at 30% of maximal spike height. Both single spikes and trains of spikes were followed by a strong, long-lasting hyperpolarization with a decay fitted by a single exponential having a time constant of 8.6 +/- 1.8 ms. Action potentials could be blocked by 10(-6) M tetrodotoxin. Spontaneously active so.n. neurons were characterized by synaptic input in the form of excitatory and inhibitory postsynaptic potentials, the latter being apparently blocked when 4 M KCl electrodes were used. Both forms of synaptic activity were blocked by application of divalent cations such as Mg2+, Mn2+ or Co2+. 74% of so.n. neurons fired spontaneously at rates exceeding 0.1 spikes per second, with a mean for all cells of 2.9 +/- 0.2 s-1. Of these cells, 21% fired slowly and continuously at 0.1 - 1.0 s-1, 45% fired continuously at greater than 1 Hz, and the remaining 34% fired phasically in bursts of activity followed by silence or low frequency firing. Spontaneously firing phasic cells showed a mean burst length of 16.7 +/- 4.5 s and a silent period of 28.2 +/- 4.2 s. Intracellular recordings revealed the presence of slow variations in membrane potential which modified the neuron's proximity to spike threshold, and controlled phasic firing. Variations in synaptic input were not observed to influence firing in phasic cells.
利用细胞内和细胞外记录技术，在丘脑下部切片标本中对视上核（SON）神经元的电特性进行了研究，并通过注射路西弗黄CH染料来标记记录部位为视上核。对视上核神经元的细胞内记录显示，它们的平均膜电位为-67±0.8mV（平均值±标准误），膜电阻为145±9MΩ，在超极化方向从40mV到去极化方向的动作电位阈值水平具有线性电流-电压关系。平均细胞时间常数为14±2.2ms。视上核动作电位的幅度在55至95mV之间，平均值为76±2mV，在最大动作电位高度的30%处的峰宽为2.6±0.5ms。单个动作电位和一连串动作电位之后都会跟随一个强烈的、持久的超极化，其衰减符合时间常数为8.6±1.8ms的单指数函数。动作电位可被10⁻⁶M的河豚毒素阻断。自发活动的视上核神经元的特征是存在兴奋性和抑制性突触后电位形式的突触输入，当使用4M KCl电极时，后者明显被阻断。两种形式的突触活动都可通过施加二价阳离子如Mg²⁺、Mn²⁺或Co²⁺来阻断。74%的视上核神经元以超过每秒0.1次动作电位的频率自发放电，所有细胞的平均值为2.9±0.2s⁻¹。在这些细胞中，21%以0.1 - 1.0s⁻¹的频率缓慢持续放电，45%以大于1Hz的频率持续放电，其余34%以阵发性活动放电，随后是静息或低频放电。自发放电的阵发性细胞的平均爆发长度为16.7±4.5s，静息期为28.2±4.2s。细胞内记录显示膜电位存在缓慢变化，这种变化改变了神经元接近动作电位阈值的程度，并控制阵发性放电。未观察到突触输入的变化会影响阵发性细胞的放电。
