周边γ-氨基丁酸通过GABA_B受体调控骶髓后联合核神经元谷氨酸能突触

目的研究突触周边γ-氨基丁酸(ambient GABA)通过GABAB受体调控骶髓后联合核(SDCN)神经元谷氨酸能突触的机制。方法在急性切取的骶段脊髓薄片上,利用全细胞膜片钳法记录骶髓后联合核神经元谷氨酸能兴奋性突触后电流(EPSCs),将GABAB受体用其特异性受体拮抗剂CGP52432阻断,观察谷氨酸突触终末上的GABAB受体被周边GABA作用的影响。结果在突触后GABAB受体被从胞内阻断的条件下,再灌流CGP52432阻断谷氨酸能突触前GABAB受体,可增加刺激引发的EPSCs(eEPSCs)幅度;改变配对刺激的两个EPSC比率(paired-pulse ratio,PPR),并激发沉默突触(silent synapse)。但CGP52432对微小兴奋性突触后电流(mEPSCs)无影响。结论位于SDCN神经元谷氨酸能突触前的GABAB受体受周边GABA调控。这种影响参与调节谷氨酸释放并可能参与痛觉信息在脊髓水平的传递。     

辣椒素受体参与骶髓后联合核神经元突触传递

目的研究辣椒素受体对大鼠骶髓后联合核(SDCN)神经元突触传递的影响。方法在脊髓骶段横切薄片上,利用全细胞膜片钳法记录骶髓后联合核神经元谷氨酸能兴奋性突触后电流(EPSCs)和γ-氨基丁酸(GABA)能抑制性突触后电流(IPSCs),比较激动辣椒素受体后上述突触电流的变化;观察激动辣椒素受体对SDCN神经元动作电位发放的影响。结果辣椒素受体被其特异性激动剂辣椒素(1μmol.L-1)激动后,自发EPSCs(sEPSCs)的频率和振幅均有明显增加(P<0.05,n=17)。在河豚毒素(0.5μmol.L-1)存在的条件下,辣椒素明显增加微小EPSCs(mEPSCs)的频率(P<0.01,n=13),但对mEPSCs的振幅无影响(P>0.05,n=13),提示辣椒素的作用在突触前。辣椒素也明显增加动作电位发放(P<0.05,n=19)。上述作用均可被辣椒素受体特异性拮抗剂capsazepine(10μmol.L-1)阻断。辣椒素也增加GABA能的自发IPSCs(sIPSCs)的频率(P<0.05,n=20),但对其不依赖动作电位的微小IPSCs(mIPSCs)的频率或振幅均无作用(P>0.05,n=9)。结论在SDCN,辣椒素受体主要表达于兴奋性突触终末;激动辣椒素受体影响兴奋性和抑制性突触活动,并可能参与痛觉信息在脊髓水平的传递和调制。     

大鼠骶髓后连合核神经元的分离

To isolate rat sacral dorsal commissural neurons (SDCN). METHODS: Using enzymatic and mechanical dissociation techniques to isolate the neurons and using nystatin perforated patch technique to evaluate their functional state. RESULTS: The isolated neurons exhibited good responses to excitatory and inhibitory amino acids. The responses of SDCN to N-methyl-D-aspartate were markedly potentiated by substance P and trans-1-aminocyclopentane-1,3-dicarboxylate, whereas GABA responses were significantly potentiated by diazepam, pregnenolone, and pentobarbital. CONCLUSION: This preparation provides a satisfactory model for exploring the mechanisms of the SDCN in nociception and antinociception.     

锌离子对大鼠骶髓后连合核神经元甘氨酸激活的全细胞电流的调控

目的研究锌离子对急性分离的大鼠骶髓后连合核神经元甘氨酸激活全细胞电流的调控。方法采用制霉菌素穿孔膜片钳方法。结果锌离子（10～1000μmol·L-1）呈浓度依赖性地抑制甘氨酸激活的全细胞电流。结论在大鼠骶髓后连合核，锌离子对甘氨酸激活的电流呈单相调控作用，即高浓度（≥10μmol·L-1）的锌离子抑制甘氨酸的反应，而低浓度（＜10μmol·L-1）的锌离子则无此作用。     

戊巴比妥对大鼠体外骶髓后联合核神经元的双重作用

AIM: To study the effects of pentobarbital (PB) on acutely dissociated rat sacral dorsal commissural neurons (SDCN). METHODS: Nystatin-perforated patch clamp recording was used. RESULTS: (1) At a holding potential of -40 mV, PB induced inward Cl- current (IPB) in a concentration-dependent manner with a EC50 (95% confidence limits) of 416 (385-477) mumol.L-1 and a Hill coefficient of 1.08. (2) Picrotoxin reversibly blocked IPB. (3) The reversal potential of IPB was close to the Cl- equilibrium potential. (4) PB enhanced GABA-induced Cl- influx (IGABA). In the presence of PB 30 mumol.L-1, the EC50 (95% confidence limits) of IGABA decreased from 6.9 (5.4-8.4) mumol.L-1 to 3.5 (2.9-4.1) mumol.L-1. CONCLUSION: PB had dual effects on SDCN, facilitated GABAA receptor-mediated currents and at higher concentrations induced Cl- influx itself.     

大鼠髓核自身免疫反应的研究

目的 探讨动物模型中将自身髓核埋置在皮下腔隙,是否能引起T、B淋巴细胞的激活.方法 从12只大鼠的椎间盘巾取得自身髓核组织,放置在有孔的钛笼内,植入皮下.在每只大鼠的皮下还植入一个空的肽笼作为对照.7 d后处死大鼠并取出钛笼.使用流式细胞术检测钛笼内外周组织叶的辅助T细胞(CD4+),细胞毒性T细胞(CD8+),CD45RC+高表达的T细胞以及IgG+的B细胞.结果 与空的钛笼作比较,装有自身髓核组织钛笼的周围组织中,活化的T细胞(CD4+/CD8+)、B淋巴细胞(IgG+)以及CIM5RC+高表达的T细胞的比例明显增高.结论 大鼠自身髓核组织暴露于自身免疫系统中.可激活T、B细胞,引起自身免疫反应.     

腰椎髓核摘除术后椎间隙感染的诊断治疗

目的探讨腰椎髓核摘除术后椎间隙感染的诊断及治疗方法。方法对本院10年来7例腰椎髓核摘除术后椎间隙感染的病例进行回顾性分析。对于早期有迹象表明术后椎间隙感染的患者,治疗要求上绝对卧床,早期静脉联合应用大剂量抗生素,并适当给予激素;2周后没有明显疗效的患者,且腰部症状进行性加重,伴有抽搐及高热等症状或者高热消退后再次出现高热的患者,应尽早行病灶清除及灌洗引流术。结果 7例椎间隙感染患者,非手术治疗4例,手术治疗3例。7例患者均治愈,术后6～12周在腰椎保护下行走。随访6个月～1年,效果优良。结论发现椎间隙有感染的迹象,应尽早治疗,一旦保守治疗效果较差,应立即行病灶清除及灌洗引流术。     

氯苯氨丁酸抑制脊髓背角神经元谷氨酸量子释放的机制

目的　研究GABAB 受体特异性激动剂氯苯氨丁酸(baclofen)在脊髓背角神经元抑制谷氨酸量子释放的机制。方法　在脊髓薄片标本上 ,采用全细胞电压钳法记录脊髓背角神经元谷氨酸能的微兴奋性突触后电流 (miniatureexcita torypostsynapticcurrents;mEPSCs) ,通过分析这些电流的变化来研究baclofen影响谷氨酸量子释放的机制。结果　ba clofen抑制mEPSCs的发放频率 ,但对平均幅度无明显影响 ,表明baclofen抑制谷氨酸释放的作用部位在突触前。在无钙溶液或者K+ 通道阻滞剂 4 AP存在的条件下 ,baclofen对mEPSCs发放频率的抑制作用不受影响 ,但腺苷酸环化酶激动剂foskolin (可使cAMP保持在较高水平 )能降低其抑制作用。而蛋白激酶C (PKC)激动剂PDBu对baclofen的抑制作用无影响。用NEM破坏G蛋白 ,则可取消baclofen的抑制效果。结论　baclofen不是通过影响突触前Ca2 + 通道或K+通道 ,或PKC途径 ,而是通过作用于G蛋白和 (或 )cAMP途径抑制谷氨酸的释放 ;这种抑制作用可能参与baclofen在脊髓水平的镇痛     

骨髓单个核细胞对大鼠脊髓损伤后行为功能影响的研究

目的:通过建立大鼠脊髓半横断模型,观察骨髓单个核细胞(BMMNCs)对大鼠后肢功能及受损脊髓组织中神经营养因子3(NT-3)表达的影响。方法:无菌条件下取大鼠双侧股骨和胫骨骨髓细胞,用Ficoll密度梯度离心法分离出单个核细胞备用。将104只Wistar大鼠随机分为A组(假手术组),8只;B组(PBS对照组),48只;C组(BMMNCs实验组),48只。大鼠术后1d、3d、5d、7d、14d和21d行BBB评分后,用免疫组织化学技术观察各组大鼠受损脊髓组织中NT-3的表达。结果:各个时间点BBB评分测试表明A组较B、C组分值高(P<0.05);B组分值较C组低(P<0.05)。免疫组织化学技术检测显示各个时间点C组大鼠受损脊髓中NT-3的表达量高于B组(P<0.05),A组与B、C组比较,差异均有统计学意义(P<0.05)。结论:BMMNCs能够促进损伤脊髓组织中NT-3的表达,可能是其修复损伤脊髓,促进脊髓功能恢复的机制之一。     

Potentiation of inhibitory amino acid receptors-mediated responses by lanthanum in rat sacral dorsal commissural neurons

Lanthanum is one of rare earth cations with extremely active chemical property and has been reported to influence neuronal transmitter systems. To date, little attention has been directed towards the sacral dorsal commissural nucleus (SDCN), which serves as a relay of sensory information from the pelvic viscera in the spinal cord. Therefore, the effect of lanthanum on the inhibitory neurotransmitter γ-aminobutyric acid (GABA) and glycine (Gly) responses in neurons acutely dissociated from the rat SDCN was investigated using the nystatin-perforated patch-recording configuration under voltage-clamp conditions. At a holding potential of − 40 mV, La³⁺ reversibly potentiated GABA (3 μM)-activated currents (I_GABA) in a concentration-dependent manner over the concentration range of 10 μM to 30 mM, with the EC₅₀ value of 67.3 ± 16.4 μM. Similarly, La³⁺ reversibly potentiated glycine (10 μM)-activated currents (I_Gly) in a concentration-dependent manner over the concentration range of 1 μM to 1 mM, with the EC₅₀ value of 52.3 ± 10.9 μM. The effects of La³⁺ on I_GABA and I_Gly were voltage-independent. Moreover, both of the potentiations were not use-dependent and were overcome by increasing the concentration of agonist. Our results indicate that La³⁺ potentiates the inhibitory amino acid receptors-mediated responses in SDCN, which may reduce the transmission of the pelvic visceral information. The information provided by this work may help to elucidate the mechanisms and effects of lanthanum on brain functions.     

Dual effects of pentobarbital on rat sacral dorsal commissural neurons in vitro

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大鼠脊髓颈段前角运动神经元核团分布

目的 观察大鼠脊髓颈段前角运动神经元分布特征.方法 取12只SD大鼠颈段和T1、T2脊髓横断面冰冻切片,用焦油紫和Pal-Weigert 染色法染色.在显微镜下观察SD大鼠颈段脊髓的前角运动神经元的分布.对SD大鼠颈段的前角运动神经元的分布特征进行研究.结果 在颈段的膨大处大鼠的前角运动神经元的核团可以分为三组:内侧...     

5-HT potentiation of the GABAA response in the rat sacral dorsal commissural neurones

1. The modulatory effect of 5-hydroxytryptamine (5-HT) on the γ-aminobutyric acid_A (GABA_A) response was investigated in the neurones freshly dissociated from the rat sacral dorsal commissural nucleus (SDCN) using the nystatin perforated patch recording configuration under the voltage-clamp conditions.
2. 5-HT potentiated GABA-induced Cl⁻ current (I_GABA) without affecting the reversal potential of I_GABA and the apparent affinity of GABA to its receptor.
3. α-Methyl-5-HT mimicked the potentiation effect of 5-HT on I_GABA while ketanserine blocked it. 1-Oleoyl-2-acetyl-glycerol (OAG) potentiated I_GABA, and the effect of 5-HT on I_GABA was occluded by OAG pretreatment. In the presence of chelerythrine, 5-HT failed to potentiate I_GABA, suggesting that protein kinase C (PKC) is involved in the pathway through which the activation of the 5-HT₂ receptor potentiates the I_GABA.
4. The facilitatory effect of 5-HT on I_GABA remained in the presence of BAPTA-AM. LiCl also had no effect on 5-HT-induced potentiation of I_GABA.
5. H-89, genistein, okadaic acid and pervanadate all had no effects on 5-HT potentiation of I_GABA. Pertussis toxin treatment for 6–8 h did not block the facilitatory effect of 5-HT on I_GABA.
6. The present results show that GABA_A receptor in the rat SDCN could be modulated in situ by 5-HT, one of the major transmitters involved in the supraspinal control of nociception, and that the phosphorylation of GABA_A receptor by PKC may be sufficient to support such modulation. The results also strongly support the hypothesis that the cotransmission by 5-HT and GABA has an important role in the spinal cord.

     

Stereospecific binding of 3H-haloperidol in rat dorsal spinal cord

[³H]Haloperidol as dopaminergic ligand used on pooled microdiscs punched from the rat dorsal spinal cord allowed detection of a stereospecific binding. Characteristics of such a binding: dissociation constant, Hill's slope and IC₅₀ of different specific drugs were nearly the same as those found in the striatum, which suggests the presence of individualized dopaminergic receptor sites in the rat dorsal horn. Their density (B_max) is about three time lower than in the whole striatum.     

淫羊藿总黄酮抑制大鼠脊髓背角神经元甘氨酸激活的全细胞电流

目的研究淫羊藿总黄酮对急性分离的大鼠脊髓背角神经元甘氨酸激活的全细胞电流(IGly)的调控。方法在急性分离的大鼠脊髓背角神经元上,采用全细胞膜片钳方法,研究淫羊藿总黄酮对甘氨酸激活的全细胞电流的调控。结果淫羊藿总黄酮呈浓度依赖性地抑制IGly;淫羊藿总黄酮使甘氨酸的浓度-效应曲线平行右移;淫羊藿总黄酮没有改变甘氨酸受体的离子选择性。结论淫羊藿总黄酮对甘氨酸介导的反应产生抑制作用可能是由于降低了甘氨酸与其受体的亲和力。