QUANTITATIVE CHARACTERIZATION OF CERULEOSPINAL INHIBITION OF NOCICEPTIVE TRANSMISSION IN THE RAT
QUANTITATIVE CHARACTERIZATION OF CERULEOSPINAL INHIBITION OF NOCICEPTIVE TRANSMISSION IN THE RAT
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DOI：
10.1152/jn.1986.56.5.1397
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发表时间：
1986-11-01
影响因子：
2.5
通讯作者：
GEBHART, GF
中科院分区：
文献类型：
--
作者：
JONES, SL;GEBHART, GF
总共分离了51个对热有反应的背角单位，并表征了它们的感受野（即，反应特性和足够的刺激确定）在戊巴比妥麻醉，瘫痪大鼠。在51个单位中的39个单位中，检查了由局灶性电刺激产生的热诱发活动在蓝斑/蓝斑下（LC/SC）的下行抑制。研究的所有单位均对机械刺激、以最大强度对同侧胫神经进行电刺激以激活A-α、δ-和C-纤维以及对足垫的有害加热（50 ℃）作出反应。所有单位的皮肤感受野仅限于脚趾和脚垫的无毛皮肤。所有检查的神经元均位于脊髓后角的I-VI层。追踪实验证实，热诱发背角单位活动的抑制可以可靠地产生由局灶性电刺激在对侧和同侧LC/SC。在LC/SC的电刺激产生的抑制是强度，脉冲持续时间和频率依赖性。在六个实验中，使用两个脉冲持续时间（100和400微秒）比较LC/SC刺激产生的热诱发活动抑制的功效;在400微秒脉冲持续时间的较低刺激强度下产生更大的热诱发活动抑制。在10个实验中，刺激的频率是不同的（25 - 200 Hz）; 100 Hz频率的电刺激对LC/SC内（n = 7）和外（n = 3）刺激部位的热诱发活动产生最大抑制。LC/SC内（n = 18）部位的局灶性电刺激可以可靠地产生热诱发背角单位活动的抑制。.伤害性热诱发的脊髓神经元活动的显着下降抑制也可以通过位于LC/SC外的脑桥部位的刺激产生，但是，不可靠。通过脑桥，使用100微安的搜索刺激，定位网站内侧，外侧和腹侧的LC/SC，从显着的下降抑制可以产生系统的电极轨道。在LC/SC外的156个位点中以100 microA进行刺激，仅在37个位点中产生热诱发脊髓单位活动抑制至对照的50%或更低。从这37个站点中的14个站点定量表征下降抑制;通过实验确定抑制热诱发活性至对照的50%的刺激的平均强度，并计算抑制刺激的平均阈值和平均募集指数。（400字处截断摘要）
A total of 51 dorsal horn units responsive to heat were isolated and their receptive fields characterized (i.e., response properties and adequate stimuli determined) in pentobarbital-anesthetized, paralyzed rats. In 39 of the 51 units, the descending inhibition of heat-evoked activity produced by focal electrical stimulation in the locus ceruleus/subceruleus (LC/SC) was examined. All units studied responded to mechanical stimulation, to electrical stimulation of the ipsilateral tibial nerve at intensities supramaximal to activate A-alpha, delta- and C-fibers, and to noxious heating (50 degrees C) of the footpad. The cutaneous receptive fields of all units were confined to the glabrous skin of the toes and footpad. All neurons examined were located in the dorsal horn of the spinal cord in laminae I-VI. Tracking experiments established that inhibition of heat-evoked dorsal horn unit activity could be reliably produced by focal electrical stimulation in both the contralateral and ipsilateral LC/SC. The inhibition produced by electrical stimulation in the LC/SC was intensity-, pulse duration-, and frequency-dependent. In six experiments, the efficacy of LC/SC stimulation-produced inhibition of heat-evoked activity was compared using two pulse durations (100 and 400 microseconds); greater inhibition of heat-evoked activity was produced at lower intensities of stimulation at the 400-microseconds pulse duration. In 10 experiments, the frequency of stimulation was varied (25-200 Hz); stimulation at a frequency of 100 Hz resulted in maximal inhibition of heat-evoked activity for stimulation sites both inside (n = 7) and outside (n = 3) the LC/SC. Inhibition of heat-evoked dorsal horn unit activity could be reliably produced by focal electrical stimulation in sites inside the LC/SC (n = 18). Significant descending inhibition of noxious heat-evoked spinal neuronal activity could also be produced by stimulation in pontine sites located outside the LC/SC, however, not as reliably. Systematic electrode tracks were made through the pons, using a searching stimulus of 100 microA, to locate sites medial, lateral, and ventral to the LC/SC from which significant descending inhibition could be produced. Stimulation in 156 sites outside the LC/SC at 100 microA produced inhibition of heat-evoked spinal unit activity to 50% of control or less in only 37 sites. Descending inhibition was characterized quantitatively from 14 of these 37 sites; the mean intensities of stimulation to inhibit heat-evoked activity to 50% of control were experimentally determined, and the mean thresholds of stimulation for inhibition and the mean recruitment indices were calculated.(ABSTRACT TRUNCATED AT 400 WORDS)