下丘脑冠状切片视上核神经元的电生理特性

Electrophysiological Characteristics of Supraoptic Nucleus Neurons in Rat Hypothalamic Slice

目的了解下丘脑冠状切片视上核神经元的电生理特性。方法在下丘脑冠状切片（厚５００μｍ）对视上核神经元进行细胞内生物电记录。结果测得静息电位（－５８±７） ｍＶ（ｘ± ｓ， ｎ＝４４），膜斜率电阻（１９５±８３）ＭΩ，时间常数（１０．８± ５．０）ｍｓ，膜电容（６０±２０）ｐＦ，动作电位幅度（６７± ９）ｍＶ，阈电位（－４２ ±８）ｍＶ，半幅时程（２．１±１．１）ｍｓ，超射（１１±５）ｍＶ。在记录的１１３个细胞中，３１．９％的细胞有自发锋电位发放，其中５．５％为持续型（紧张型）放电，７０．６％为时相型放电，其余为不规则放电。在时相型放电的细胞可观察到自发的慢去极化电位。长时程去极化时锋电位发放呈明显的适应现象。顺行电刺激可诱发兴奋性突触后电位，并具有刺激强度依赖性。结论提示视上核神经元作为神经内分泌细胞具有与其他神经元不同的电生理特性。

Objective To realize the electrophysiological characteristics of supraoptic nucleus neurons in rat hypothalamic coronal slices. Methods in hypothalamic slices (500μm thick) coronally prepared from adult male Sprague-Dawley rats, the intracellular recordings were made from supraoptic nucleus(SON) neurons. Results The resting poential, slope resistance, time constant, membrane capacitance, the amplitude of action potential, threshold level, half-peak duration and over-shoot were measured to be (-58±7)mV(x±s,n=44), (195± 83)MΩ, (10. 8±5.0)ms, (60±20)pF,(67±9)mV,(-42±8) mV,(2. 1±1. 1) ms, (11±5) mV. Of 113 tested SON cells, 31.9% presented spontaneous spike firings, in which 5.5% discharged in a continuous model, 70.6% in a phasic model and the rest in a irregular form. A spontaneous slow depolarization could be observed in the phasic firing cells. The spike firing presented typical adaptation during long-pulse depolarizing current injection. A stimulus intensity-dependent excitatory postsynaptic potential was evoked by orthodromic stimulation. Conclusions SON neurons as the neuroendocrine cells exhibit some electrophysiological characteristics different from other neurons.