CONNECTIONS OF SUPERFICIAL DORSAL HORN NEURONS

本研究将考察它们之间的联系、功能特性和 大鼠脊髓背角神经元的化学成分 去掉猫和老鼠的大脑。进一步认识这些因素的作用 细胞可能会带来治疗人类严重疼痛的更好方法。四 提出了相关的研究项目：(1)大鼠脊髓背角浅层神经元 板层1-2和板层3-6的深层神经元对 刺激与阿片类药物相关的下行通路和 “刺激产生”的止痛将以细胞内为特征 染料标记和多肽或酶的免疫组织化学染色 内容。 (2)1-2板层神经元的轴突轨迹将由 细胞外和细胞内单单位记录和系统化 利用不同强度刺激的详细逆行标测 通过低阻抗微电极传递。代表单位将 用细胞内染色和免疫组织化学方法进行检测。 (3)背角神经元对的活动，一对在板层1-3，一对在板层。 在3-6层更深的第二层，将使用同时单次关联 单位记录、尖峰触发平均和后刺激的计算 重复刺激下行和传入时的时间直方图 系统。如果找到一致的关联模式，则具有代表性 单位--成对中的一个或两个--将由细胞内标识 染色和免疫组织化学技术。(4)接受场和 浅层背角的单个神经元的活动将是 全身麻醉诱导前、中、后检查 戊巴比妥或α-氯醛糖。个别单位之后将会有 长时间的细胞外单个单元记录，具有重复映射 外周感受野。代表单位将被穿透并 通过细胞内染料标记进行鉴定。

This research will examine the connections, functional properties and chemical content of neurons in the dorsal horn of the spinal cord in decerebrate cats and rats. Further understanding of the role of these cells could lead to better means of treating severe pain in humans. Four related projects are proposed: (1) Superficial dorsal horn neurons of laminae 1-2 and deeper neurons of laminae 3-6 which show responses to stimulation of descending pathways relevant to opiate and 'stimulation-produced' analgesia will be characterized by intracellular dye-labelling and by immunohistochemical staining for peptide or enzyme content. (2) Axon trajectories of neurons in laminae 1-2 will be traced by extracellular and intracellular single unit recording and systematic detailed antidromic mapping using stimulation of varying intensities delivered through low-impedance microelectrodes. Representative units will be marked by intracellular staining and examined immunohistochemically. (3) Activity in pairs of dorsal horn neurons, one in laminae 1-3 and the second deeper in laminae 3-6, will be correlated using simultaneous single unit recordings, spike-triggered averaging, and computation of poststimulus time histograms during repetitive stimulation of descending and afferent systems. If consistent patterns of correlation are found, representative units -- one or both of pair -- will be identified by intracellular staining and by immunohistochemical techniques. (4) Receptive fields and activity of individual neurons in the superficial dorsal horn will be examined before, during and after induction of general anesthesis with pentobarbital or alpha-chloralose. Individual units will be followed by prolonged extracellular single unit recordings with repeated mapping of peripheral receptive fields. Representative units will be penetrated and identified by intracellular dye marking.