Hoffman N W, Tasker J G, Dudek F E
Mental Retardation Research Center, UCLA Center for the Health Sciences 90024.
J Comp Neurol. 1991 May 15;307(3):405-16. doi: 10.1002/cne.903070306.
Intracellular recording and labeling were combined with neurophysin immunohistochemistry to study neurons in the paraventricular nucleus region of the rat hypothalamus. Neuronal membrane properties were examined in hypothalamic slices, and cells were labeled by injecting biocytin or Lucifer yellow. Slices were then embedded, sectioned, and immunohistochemically processed for neurophysin. Immunoreactivity patterns, and in some cases counterstaining, enabled determinations of the cytoarchitectonic positions of recorded cells to be made. Recorded cells were divided into three types according to their electrophysiological characteristics. The first type lacked low-threshold Ca2+ spikes and displayed linear current-voltage relations, a short time constant, and evidence for an A current. These were relatively large cells that were typically immunoreactive for neurophysin and were situated near other neurophysin-positive neurons. The second type had relatively small low-threshold potentials that did not generate bursts of Na+ spikes. These cells had heterogeneous current-voltage relations and intermediate time constants. They did not label for neurophysin, and most were located in the parvicellular subregion of the paraventricular nucleus. The third type had large low-threshold Ca2- spikes that generated bursts of Na+ spikes, and these cells had nonlinear current-voltage relations and long time constants. These neurons were dorsal or dorsolateral to the paraventricular nucleus and were not immunoreactive for neurophysin. These results indicate that paraventricular magnocellular neurons lack low-threshold potentials, whereas paraventricular parvicellular neurons display low-threshold potentials that generate one or two action potentials. Neurons that fire spike bursts from low-threshold potentials are adjacent to the paraventricular nucleus, confirming earlier reports.
细胞内记录和标记与神经垂体素免疫组织化学相结合，用于研究大鼠下丘脑室旁核区域的神经元。在脑片上检测神经元膜特性，通过注射生物胞素或荧光黄对细胞进行标记。然后将脑片包埋、切片，并进行神经垂体素的免疫组织化学处理。免疫反应模式以及在某些情况下的复染，能够确定所记录细胞的细胞构筑位置。根据记录细胞的电生理特性，将其分为三种类型。第一类细胞缺乏低阈值Ca2+峰电位，呈现线性电流-电压关系、短时间常数以及A电流的证据。这些细胞相对较大，通常对神经垂体素呈免疫反应阳性，且位于其他神经垂体素阳性神经元附近。第二类细胞具有相对较小的低阈值电位，不会产生Na+峰电位爆发。这些细胞的电流-电压关系各异，时间常数处于中等水平。它们对神经垂体素无标记，且大多数位于室旁核的小细胞亚区域。第三类细胞具有大的低阈值Ca2+峰电位，可产生Na+峰电位爆发，这些细胞具有非线性电流-电压关系和长时间常数。这些神经元位于室旁核的背侧或背外侧，对神经垂体素无免疫反应。这些结果表明，室旁核大细胞神经元缺乏低阈值电位，而室旁核小细胞神经元表现出能产生一或两个动作电位的低阈值电位。从低阈值电位发放峰电位爆发的神经元与室旁核相邻，证实了早期的报道。
