ELECTROPHYSIOLOGICAL STUDIES ON THE TERMINATION SITES OF DOUBLE PROJECTION SPINAL DORSAL HORN NEURONS IN THE CAT

Some projection neurons in laminae Ⅲ, Ⅳ and Ⅴ of the felline lumbar dorsal horn have been found to be antidromically driven from stimulation of both the ipsilateral cervical dorsal and dorsolateral funiculi that are well-dissected and insulated from one another. No detectable responses can be evoked from these nenrons when stimulation is applied to sites rostral to the lateral cervical nucleus and the dorsal column nuclei, suggesting that the dorsal and dorsolateral funicular branches of these neuron's axons terrninate in the lateral cervical nucleus and the dorsal column nuclei, respectively. The results indicate that these neurons axe an intersection set of the spinal cervical tract (SCT) and dorsal column postsynaptic (DCPS) neurons and have been thus named spinal cervical tract-dorsal column postsynaptie (SCT-DCPS) neurons.     

发育期培养脑细胞膜电学特性的研究

在大鼠胎鼠脑细胞原代单层细胞培养的条件下,从发育早期,观察了神经元膜的电学参数及其在离子通道阻断剂作用下的变化。发育;Ⅰ—Ⅳ期脑细胞的静息膜电位相对值分别为1,3.46,4.07,6.54;膜输入阻抗的相对值分别为1,1.48,2.53,4.56,Ⅱ,Ⅲ期电流电压关系在去极化方向上,按指数曲线变化。自发动作电位的发生率随培龄增加;Ⅲ,Ⅳ期诱发电位振幅达最高值。TEA细胞外灌流下,Ⅲ,Ⅳ期脑细胞的膜电位和输入阻抗显著下降,但TTX灌流无何影响。结果提示:培养脑细胞膜的钾通道发育Ⅰ,Ⅲ期较快,Ⅱ,Ⅳ期较缓,Ⅳ期未臻于成熟。     

“足三里”-脊髓背角-孤束核的机能联系

在戊巴比妥钠麻醉的大鼠上,应用电刺激足三里穴(ZSL)和孤束核(SN)及腰髓背角Ⅲ—V板层微电极细胞内记录技术。发现并鉴定了57个对ZSL和SN电刺激均有反应的脊髓神经元。其中34个可被SN逆向激动,其余对SN发生突触反应。所有神经元对ZSL刺激均发生顺向反应,LTM型和WDR神经元约各占一半。结果提示:(1)同一个脊髓背角神经元可接受来自ZSL的躯体传入信息,并将其传递给内脏感觉核团——SN;(2)脊髓背角神经元也可接受SN的下行神经支配;(3)躯体传入与内脏传入两种信息可在脊髓背角神经元或SN内汇聚和整合。     

THE PROPERTY OF PERIPHERAL INPUT OF PROJECTION NEURONS IN THE SPINAL CORD DORSAL HORN

Antidromic and orthodromic responses of the projection neurons in the dorsal horn ofthe spinal cord have been recorded by a glass microelectrode in anesthetized and paralyz-ed cats. Furthermore, the effect of cervical segment antidromic stimulation to orthodromicresponse of the projection neurons has been observed by way of conditioning-test stimulation. Among all the spinocervical tract neurons (SCT), the dorsal column postsynaptic neu-rons (DCPS) and the spinocervical tract-dorsal column postsynaptic neurons (SCT-DCPS),which were identified by cervical segment antidromic stimulation, 46% are low-thresholdmechanoreceptive (LTM) and 54% are wide-dynamic-range (WDR) neurons. Most LTMneurons can evoke the same response to both 10 times (10 T) and 50 times (50 T) the thresh-old stimulation on the peroneal nerve. Most WDR neurons to 50 T intensity stimulation arestronger than the 10 T stimulation. Under the antidromic-cervical segment conditioningstimulation, the amount of orthodromic-discharging in most WD     

DEVELOPMENTAL STUDIES OF ELECTRICAL PROPERTIES IN CULTURED RAT BRAIN NEURONS

The rat brain neurons isolated from 15—17-day embryos were grown in dissociated cell culture and maintained in vitro for 3 weeks, The developmental process of the neurons was observed from the early stage of development in terms of passive and active electrical parameters and their changes induced by perfusion of ionic channel blockers.The neurons' development could be morphologically divided into stages Ⅰ (from seedling to 5 days), Ⅱ (7—11 days), Ⅲ (12—20 days)andlV (21—22 days). The relative values of resting membrane potentials (RMP) for stages Ⅰ, Ⅱ, Ⅲ and Ⅳ were 1, 3.46, 4.07 and 6.54, respectively; the corresponding values of input resistance (Rin) were 10 1.48, 2.53 and 4.56, respectively. The current-voltage relationship in stages Ⅱ and Ⅲ was exponential in the direction of depolarization and the Rin's change with time was nearly linear. Spontaneous activities increased with prolongation of culture and the amplitude of evoked action potentials reached the maximum during stages Ⅲ and     

“足三里”针刺镇痛效应外周传入神经纤维的分析

针刺“足三里”穴对以下颌运动反应为指标的痛模型具有显著的抑制效应,引起这一效应的,来自“足三里”穴的针刺镇痛冲动主要由腓神经中Aβγ传入纤维传递;足够数量的Aβγ纤维活动是产生显著镇痛效应的重要因素.传递镇痛冲动的Aβγ类粗纤维对传递致痛冲动的Aδ和C类细纤维的抑制作用,看来是针刺镇痛原理的一个组成部分。     

The Functional Linkage Among the "ZSL"-Spinal Dorsal Horn-SN

Electrical stimulation of the Zusanli point (ZSL) and solitary tract nucleus (SN) as well as microelectrode recording from the laminae Ⅲ-Ⅴ of the lumbar spinal dorsal horn have been used on the pentobarbital anesthetized rats, finding and identifying 57 spinal neurons responding to the stimulations of both ZSL and SN. Among them, 34 responded antidromically to SN; the others responded orthodromically to SN. Among them, the lowthreshold mechano-receptive(LTM) neurons and wide-dynamic-range (WDR) neurons were 50 percent respectively. The results indicate that (ⅰ) a single spinal dorsal horn neuron receives somatic afferent input and then conveys it to the visceral sensory nucleus-SN; (ⅱ) some spinal dorsal horn neurons receive, in turn, innervation from the SN; (ⅲ) the convergence and integration between somatic and visceral sensory inputs might occur in the spinal dorsal horn neurons and/or SN.     

THE PROJECTION LINKAGE BETWEEN THE SPINAL DORSAL HORN NEURONS AND BOTH THE SOLITARY TRACT AND DORSAL COLUMN NUCLEI

Electrical stimulation of the solitary tract nucleus (SN) and dorsal column nuclei (DCN)as well as microelectrode recording from the lumbal spinal dorsal horn have been used tofind and identify the axonal projection of and the afferent innervation on the spinal neuronsof pentobarbital- anesthetized rats. A total of 92 neurons was recorded and identified mainly in laminae Ⅲ-Ⅴ of the lumbarspinal dorsal horn. Of them, 38 neurons were activated antidromically from stimulation ofboth the SN and DCN. The other 54 neurons responded synaptically to both the SN andDCN stimulations. The initial antidromic responses of 8 neurons in the first group werefollowed by one or more responses synaptically driven from the SN and/or DCN stimulation.Conduction velocities were in the range of A delta fibers, but faster in the antidromicresponses and slower in the synaptic responses. These results indicate that (i) some spinal neurons issue branched axons of larger-sizedA delta fibers and double project to both the SN and D     

INTRASPINAL CONNECTIONS OF DORSAL COLUMN POSTSYNAPTIC NEURONS IN THE CAT——A PHYSIOLOGICAL ANALYSIS

Dorsal column postsynaptic (DCPS) neurons in the dorsal horn of the spinal cord have been identified by antidromic stimulation and intracellularly recorded in anesthetized cats. In about one-half of the cells, the antidromic stimulus evokes only an antidromic potential. This potential sometimes has an atypical shape due to penetration-induced depolarization. Atypieal potentials arc converted into typical antidromic spike potentials after intracellular injection of hyperpolarizing current. In the other one-half, the antidromic potentials are followed by postsynaptic activity. Intracellular analysis indicates that this postsynaptic activity is generated largely by activation of the intraspinal collaterals of A-beta primary afferents that are ascending the dorsal columns. Part of this postsynaptic activity has been produced monosynaptically. Polysynaptic responses are also evident; these are thought to be initiated by A-beta axons, desending axons from neurons in the dorsal column nuclei, or the local coll     

脊髓背角神经元同孤束核及背索核的投射联系

在以戊巴比妥钠麻醉的大鼠上,应用电刺激孤束核(SN)和背索核(DCN)以及腰髓背角微电极记录技术,发现并鉴定脊髓神经元的轴突投射和传入支配。在腰髓背角Ⅲ—Ⅴ板层共记录和鉴定了92个神经元。其中38个神经元可被SN和DCN双重地逆向激动;其余54个神经元既对SN又对DCN的刺激发生突触反应;8例发生双重逆向反应的神经元还对SN和/或DCN的刺激发生突触反应。逆向和突触反应的传导速度均属Aδ纤维,但前者较快,后者较慢。结果提示,(1)有些脊髓神经元发出较粗的Aδ分叉轴突,向SN和DCN进行双投射;(2)这种双投射神经元有的还从SN和/或DCN接受较粗Aδ纤维支配;(3)另一些脊髓神经元受来自SN和DCN较细Aδ纤维的双重支配。