Optical mapping of functional organization in the early embryonic brain stem using multiple-site recording of neural activity together with voltage-sensitive dyes.

在分离的3~8日龄鸡胚胎的迷走神经/脑干的完整和切片标本中，用电压敏感的花青红-罗丹宁染料(NK2761)和12×12元光电二极管阵列，用多点电活动光学记录来评估迷走神经刺激的神经反应及其发育的空间模式。在制备过程中，用正方电流脉冲刺激迷走神经，同时记录了127个连续位点的电压相关光(吸光度)变化。测量是通过光电二极管阵列在制备图像上的连续位移来进行的。在4天龄的脑干标本中记录到第一神经反应，即与动作电位相关的快光信号，而在7天和8天龄的脑干标本中检测到慢光信号。连续的S…使慢信号的大小减小更多的刺激，减少低的外部钙离子浓度，并消除存在的锰或镉离子。慢信号在犬尿酸存在下被消除，并被2-APV(DL-2-氨基-5-膦-戊酸)和CNQX(6-氰基-7-硝基-2，3-二酮)还原。我们的结论是，慢信号对应于兴奋性突触后电位，而兴奋性突触后电位是谷氨酸介导的。诱发的光信号似乎纵向集中在完整脑干标本刺激侧的中央区域，而在切片标本的有限背侧区域。随着发育的进行，信号的大小逐渐增大，响应面积逐渐扩大。基于上述结果，我们构建了快反应和慢反应的空间模式发展图。在这些图中，我们评估了快信号和慢信号的峰大小区域的位置，我们发现在7天和8天的晚期胚胎脑干标本中，快信号和慢信号的峰大小区域的相对位置存在差异。快信号反应区似乎对应于迷走神经背侧运动核，慢信号反应区对应于孤束核。较少

In intact and slice preparations of the vagus/brain stem isolated from 3-to 8-day old chick embryos, the spatial pattern of neural responses to vagal stimulation and its development were assessed by using multiple-site optical recording of electrical activity, with a voltage-sensitive merocyanine-rhodanine dye (NK2761) and a 12 x 12-element photodiode array. Voltage-related optical (absorbance) changes evoked by vagus nerve stimulation with depolarizing (positive) square current pulses using a suction electrode were recorded simultaneously from 127 contiguous loci in the preparation. The measurements were made by successive displacements of the photodiode array over the image of the preparation.The first neural responses, viz., fast optical signals related to the action potentials were recorded in the 4-day old brain stem preparations, and the slow optical signals were detected from late 7- and 8-day old brain stem preparations. The size of the slow signal was decreased by continuous s … More timulation, reduced by low external calcium ion concentrations and eliminated in the presence of manganese or cadmium ion. The slow signals were eliminated in the presence of kynurenic acid, and they were reduced by 2-APV (DL-2-amino-5-phosphono-valeric acid) and by CNQX (6-cyano-7nitroquinoxaline-2, 3-dione). We concluded that the slow signals correspond to excitatory postsynaptic potentials which are glutamate-mediated.The evoked optical signals appeared to be concentrated longitudinally in the central region on the stimulated side of the intact brain stem preparations and in a limited dorsal area in the slice preparations. The signal size gradually increased and the response area expanded as development proceeded. Based on the above results, we have constructed developmental maps of spatial patterns of the fast and slow responses. In the maps, the positions of the peak-size area of the fast and slow signals were assessed, and we have found that there were differences in the relative locations of the peak-size regions between the fast and slow signals in the late 7- and 8-day old embryonic brain stem preparations. The fast signal response area seems to correspond to the dorsal motor nucleus of the vagus nerve and the slow signal response area to the nucleus tractus solitarii. Less