Wu W L, Chuang H H
Shi Yan Sheng Wu Xue Bao. 1989 Mar;22(1):111-22.
It has been reported that in Cynops orientalis the cells in the atypical epidermis resulted from isolation of the ectoderm from the early gastrula and cultured in vitro possesses very low excitability. The great majority of the explants didn't display action potential (AP) with electric stimulus up to 6 V duration 1 ms). If, however, the epidermis was taken from the flank region of a neurula with the underlying mesoderm, in such explant the epidermis cells became excitable at a lower threshold of stimulus. The mesoderm seemed to exert some influence upon the epidermis. In order to study whether tissues other than mesoderm possess similar effect on the excitability of epidermis cells, different combinations of explants were made with the experimental embryological technique and their excitability was examined electrophysiologically. In all experiments the explants were stimulated extracellularly and the action potential was recorded intracellularly. The specimens were stimulated with electric stimulus at 6 V at first, and, if they displayed AP the strength was lowered to determine the threshold of stimulus to evoke AP. The duration of stimulus was fixed at 1 ms. For the control of all series, the ectoderm or epidermis was isolated at the same stage and cultured for the same length of period as the experimental explants but without any treatment. 1). The effect of calf serum. In this group the effect of calf serum was examined and following series were carried out: a) Gastrula ectoderm cultured in Holtfreter solution containing 10% calf serum; b) calf serum + agar as implant: calf serum was mixed with agar (1:1) and cut into small pieces when cooled, and the serum + agar pieces were wrapped with ectoderm; c) heated serum + agar, heated serum was mixed 1:1 with agar and the small pieces were wrapped with ectoderm. In all the experiments the excitability of the epidermis cells was raised more or less but the agar pieces containing fresh serum seemed to be more effective, perhaps due to the higher concentration of the serum and the intimate contact with the epidermis cells (Tab. 1) In the series with serum + agar as implant and in the series with heated serum + agar as implant, it occurred frequently that during cultivation the implants will be extruded and after the extrusion of the implant the remaining epidermis became less sensitive to stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)
据报道，东方蝾螈中，非典型表皮中的细胞源于原肠胚早期外胚层的分离，并在体外培养，其兴奋性极低。绝大多数外植体在高达6V（持续时间1ms）的电刺激下未显示动作电位（AP）。然而，如果表皮取自具有下方中胚层的神经胚的侧翼区域，在这种外植体中，表皮细胞在较低的刺激阈值下变得可兴奋。中胚层似乎对表皮有一定影响。为了研究除中胚层以外的组织是否对表皮细胞的兴奋性有类似作用，采用实验胚胎学技术制作了不同的外植体组合，并用电生理学方法检测其兴奋性。在所有实验中，对外植体进行细胞外刺激，并在细胞内记录动作电位。标本首先用6V的电刺激进行刺激，如果它们显示出动作电位，则降低刺激强度以确定诱发动作电位的刺激阈值。刺激持续时间固定为1ms。对于所有系列的对照，在相同阶段分离外胚层或表皮，并与实验外植体培养相同的时间，但不进行任何处理。1）. 小牛血清的作用。在该组中，检测了小牛血清的作用，并进行了以下系列实验：a）在含有10%小牛血清的霍尔特弗雷德溶液中培养原肠胚外胚层；b）小牛血清+琼脂植入物：小牛血清与琼脂（1:1）混合，冷却后切成小块，血清+琼脂块用外胚层包裹；c）加热血清+琼脂，加热血清与琼脂按1:1混合，小块用外胚层包裹。在所有实验中，表皮细胞的兴奋性或多或少都有所提高，但含有新鲜血清的琼脂块似乎更有效，这可能是由于血清浓度较高以及与表皮细胞的密切接触（表1）。在血清+琼脂植入物系列和加热血清+琼脂植入物系列中，在培养过程中植入物经常会被挤出，植入物挤出后，剩余的表皮对刺激变得不那么敏感。
