首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到14条相似文献,搜索用时 140 毫秒
1.
目的:探讨胞外信号调节激酶(ERKⅠ/Ⅱ)在大鼠脊髓背角C-纤维诱发电位长时程增强(LTP)的诱导和维持中的作用。 方法: 细胞外记录技术在脊髓腰膨大部记录背角浅层神经元C-纤维诱发电位。 结果: (1) MEK的选择性抑制剂PD98059(100 μmol/L)或SL327 (200 μmol/L) 对脊髓背角C-纤维诱发电位的基础电位没有影响,但可阻断脊髓背角LTP的诱导。(2) PD98059或SL327呈时间依赖性逆转脊髓背角LTP。在LTP 诱导后15 min,脊髓局部给予PD98059(100 μmol/L)或SL327(200 μmol/L)可完全逆转LTP。在LTP 诱导后30 min,单独给予PD98059或SL327,LTP的抑制率分别为62.5%与75.0%。但同样浓度的PD98059或SL327在LTP 诱导后1 h,均不能逆转业已建立的LTP。 结论: 脊髓背角ERKⅠ/Ⅱ的激活参与C-纤维诱发电位LTP的诱导和早期维持。  相似文献   

2.
小胶质细胞SFKs在ATP诱导的脊髓背角LTP中的作用   总被引:1,自引:1,他引:0       下载免费PDF全文
目的: 研究Src家族激酶(SFKs) 在5'-三磷酸腺苷(ATP)诱导的脊髓背角长时程增强(LTP)中的作用。方法: 雄性SD大鼠(250-280 g)。在体电生理记录脊髓腰膨大部背角浅层神经元C-纤维诱发电位,Western blotting和免疫组织化学观察脊髓背角SFKs的磷酸化水平和表达部位。结果: ATP应用后30 min和60 min,磷酸化的Src-家族激酶(p-SFKs)的水平明显升高;p-SFKs只表达于小胶质细胞中,星型胶质细胞和神经元中没有表达。脊髓表面应用SFKs抑制剂阻断ATP诱导的LTP。结论: 小胶质细胞SFKs可能在ATP诱导的脊髓背角C-纤维诱发电位LTP中发挥重要作用。  相似文献   

3.
目的:探讨蛋白激酶C (PKC) 在大鼠脊髓背角C-纤维诱发电位长时程增强(LTP)的诱导和维持中的作用。方法: 细胞外记录技术在脊髓腰膨大部记录背角浅层神经元C-纤维诱发电位。 结果:(1) PKC的选择性抑制剂chelerythrine(200 μmol/L)或G 6983(100 μmol/L)对脊髓背角C-纤维诱发电位的基础电位没有影响,但可完全阻断脊髓背角LTP的诱导。(2) Chelerythrine或G 6983呈时间依赖性翻转脊髓背角LTP。在LTP 诱导后15 min,脊髓局部给予chelerythrine(200 μmol/L)后,LTP逐渐降低,于给药后70 min降至对照水平;而G 6983(100 μmol/L)产生同chelerythrine相似的效应,在用药后110 min,LTP降至对照水平。但同样浓度的chelerythrine或G 6983在LTP 诱导后3 h,均不能翻转业已建立的LTP。结论: PKC参与脊髓背角C-纤维诱发电位LTP的诱导和早期维持,而不影响晚期LTP的维持。  相似文献   

4.
目的探讨长时程增强诱导和维持过程中脊髓背角钙/钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)磷酸化水平的变化。方法(1)细胞外记录脊髓腰膨大部背角浅层神经元C-纤维诱发电位;(2)免疫组化技术观察脊髓背角CaMKⅡ磷酸化水平的变化。结果(1)LTP30min、LTP3h脊髓背角CaMKⅡThr286的磷酸化水平明显高于对照组;(2)强直刺激前30min脊髓局部给予KN-93(CaMKⅡ选择性抑制剂,100μmol/L),LTP的诱导被完全阻断,CaMKⅡ磷酸化水平与对照组无明显差别;(3)强直刺激后30min给予KN-93,明显抑制LTP,CaMKⅡ的磷酸化水平也显著降低;(4)LTP3h后给予KN-93,LTP幅度和CaMKⅡ磷酸化水平与用药前相比,差异没有统计学意义。结论CaMKⅡ磷酸化可能在脊髓背角C-纤维诱发电位长时程增强诱导和早期维持中发挥重要作用。  相似文献   

5.
酪氨酸家族激酶在大鼠脊髓背角LTP中的作用及其机制   总被引:1,自引:1,他引:0  
目的: 探讨酪氨酸家族激酶(SFKs)在大鼠脊髓背角C纤维诱发电位的长时程增强(LTP)中的作用及其机制。 方法: 用在体电生理方法检测SFKs抑制剂对高频刺激坐骨神经诱导的脊髓背角LTP的影响;用Western blotting方法检测高频刺激诱导脊髓LTP的不同时点大鼠脊髓背角磷酸化SFKs的表达情况;用免疫荧光双染方法检测高频刺激诱导脊髓LTP后大鼠脊髓背角磷酸化SFKs表达的细胞学定位。 结果: SFKs的抑制剂(PP2或SU6656)可以完全阻断LTP的诱导,甚至将LTP逆转为长时程抑制(LTD);高频电刺激大鼠坐骨神经诱导脊髓LTP后15 min开始,刺激同侧的脊髓背角中磷酸化SFKs表达明显增加,并且这些高表达的磷酸化SFKs仅仅存在于脊髓小胶质细胞中。 结论: 在脊髓背角,小胶质细胞中的SFKs 是诱导LTP的必要条件,抑制SFKs及其下游分子可能有助于治疗病理性疼痛。  相似文献   

6.
目的: 探讨白细胞介素-1β (interleukin-1β, IL-1β)在神经病理性疼痛大鼠脊髓背角C纤维诱发电位长时程增强(long-term potentiation, LTP)中的作用及其机制。方法: 用坐骨神经部分损伤(spared nerve injury, SNI)和腰5前根切断(lumbar 5 ventral root transection, L5 VRT)方法复制大鼠病理性疼痛模型,观察外源性IL-1β对正常大鼠及病理性疼痛模型大鼠脊髓背角C纤维诱发电位的影响,并且检测p38 MAPK (p38 mitogen-activated protein kinase)和NF-κB (nuclear factor-kappa B)信号通路在其中的作用。结果: 500 μg/L IL-1β对正常大鼠C纤维介导的基本突触传递和高频刺激诱导的LTP都没有影响,而5 μg/L的IL-1β可以在神经病理性疼痛模型的大鼠上诱导出LTP。预先用p38 MAPK或NF-κB的抑制剂(SB203580或PDTC)可以完全阻断IL-1β诱导的LTP。结论: 外源性IL-1β可诱导神经病理性疼痛大鼠脊髓背角C纤维诱发电位的LTP。p38 MAPK和NF-κB信号通路可能参与这一过程。  相似文献   

7.
本实验用鞘内给药的方法对非选择性环氧合酶 1/ 2抑制剂吲哚美辛 (indomethacin,Indo)和选择性环氧合酶 2抑制剂Etodolac对蜜蜂毒诱致的自发缩足行为、原发性 (热和机械性 )痛敏和脊髓背角 c-fos蛋白表达的效果进行了观察 ,发现 :(1)预先用吲哚美辛和 Etodolac处理均可剂量依赖性地抑制自发缩足行为的发生 ,提示脊髓环氧合酶 2 (但不能完全排除环氧合酶 1)在长时程、持续性自发痛的诱导中具有重要作用 ;(2 )与上述结果不同 ,预先用吲哚美辛和 Etodolac处理对蜜蜂毒注入部位热刺激潜伏期缩短和机械性刺激阈值的下降无抑制作用 ,提示脊髓环氧合酶在原发性热和机械痛敏的诱导不起任何作用 ;(3 )上述两种药物的同样处理对脊髓背角 c-fos蛋白的表达均具有显著抑制作用 ,但通过对背角浅、深层细胞分别记数分析显示两种环氧合酶抑制剂只对浅层具有抑制作用 ,而对深层则无。以上结果提示 ,脊髓环氧合酶参与介导蜜蜂毒组织损伤后持续性自发痛的发生 ,但不参与原发性热和机械性痛敏的发生 ;背角浅层 c-fos阳性神经元可能不参与介导原发性痛敏的发生。  相似文献   

8.
目的:观察皮质酮(CORT)对培养的脊髓背角神经元Ca2+浓度([Ca2+]i)的调节作用及机制。方法:培养新生SD大鼠脊髓背角神经元,激光共聚焦显微镜检测神经元[Ca2+]i的变化。结果:CORT可快速升高培养的脊髓背角神经元[Ca2+]i,且呈现剂量依赖性(P0.05);CORT诱导的神经元[Ca2+]i升高是以外钙内流为主(P0.01);百日咳毒素(G蛋白活化阻断剂)可阻断CORT所致的脊髓背角神经元[Ca2+]i升高(P0.01),而糖皮质激素受体拮抗剂RU38486对CORT的效应无抑制作用。结论:CORT通过非基因组途径快速增高培养的脊髓背角神经元[Ca2+]i。  相似文献   

9.
为研究脊髓水平环氧合酶(COX)-1在术后疼痛形成和维持中的作用,运用免疫组化和免疫蛋白印记法观察切口痛模型大鼠腰段脊髓中COX-1蛋白在术前和术后2h,4h,6h,12h、1d、2d,3d、5d和7d的表达。通过测定机械刺激引起的缩足反射阈值(PWT)分别在术前、术后2h、1d、2d、3d、5d和7d观察术后痛觉超敏情况,并通过术后即刻或术后2h,24h鞘内给予非选择性COX抑制剂(ketorolac)、选择性COX-1抑制剂(SC-560)和选择性COX-2抑制剂(NS-398)观察其镇痛作用。结果表明:术后COX-1免疫反应阳性细胞主要集中在脊髓背角浅层,COX-1蛋白表达增加,4h达高峰,并且持续增加至12h。术后鞘内给予SC-560和ketorolac均能明显减轻皮肤切开诱发的机械性痛觉超敏,然而NS-398却无任何镇痛作用。本研究表明脊髓COX-1参与术后痛觉超敏的形成和维持的过程,鞘内给予COX-1抑制剂具有抗切口痛大鼠痛觉超敏的作用。  相似文献   

10.
1 痛觉诱发电位的传导路径痛觉系统生理性的诱发电位和传导径路上的表现形式为 :伤害性感受器电位→周围神经动作电位→突触后电位→传导束电位。从感受器感受刺激转换成神经冲动后 ,要经过传入纤维 (包括传导快痛的Aδ纤维和传导慢痛的C纤维 )、脊髓背角的神经元、脊髓丘脑束、丘脑的神经元和核团最后投射到达皮层体感区及有关联的皮层与核团 ,形成痛觉诱发电位[1,2 ] 。2 痛觉诱发电位的刺激形式任何可以引起疼痛的伤害性刺激均可诱发脑电位。因神经生理学检查对电刺激的应用较成熟 ,最早和最常用的是电刺激。机械压迫、超声、化学性…  相似文献   

11.
Previous studies have demonstrated that in the hippocampus the maintenance of long-term potentiation (LTP) requires de novo protein synthesis. To investigate the role of protein synthesis in the maintenance of LTP of C-fiber evoked field potentials in spinal dorsal horn, which may be relevant to hyperalgesia, protein synthesis inhibitor (either cycloheximide or anisomycin) was applied locally to the recording segments of spinal cord in anesthetized rats, 30 min prior to tetanic stimulation to the sciatic nerve. We found that both cycloheximide and anisomycin selectively inhibited late-phase maintenance of the spinal LTP but affected neither LTP induction nor baseline responses of C-fiber evoked field potentials. In the presence of cycloheximide, LTP of C-fiber evoked field potentials was 281.5 +/- 16.5% (n = 6) of baseline 1 h after tetanic stimulation and the potentiation significantly decreased to 235.5 +/- 18.5% at 145 min after tetanic stimulation (P < 0.05). Afterward, LTP of C-fiber evoked field potentials decreased continuously and at 270 min after tetanic stimulation reached 130.8 +/- 18.0%, which was no longer different from baseline (P > 0.05). Spinal application of anisomycin at 30 min before tetanic stimulation yielded similar results (n = 6). These results suggest that protein synthesis may be crucial for the late-phase maintenance of LTP of C-fiber evoked field potentials in spinal dorsal horn.  相似文献   

12.
Long-term potentiation (LTP) of C-fiber-evoked field potentials in spinal dorsal horn may be relevant to pathological pain. Our previous work has shown that the late phase of the spinal LTP is protein synthesis-dependent. Considerable evidence has accumulated that dopamine D1/D5 receptors are important for late-phase LTP in hippocampus. In this study, the role of D1/D5 receptors in LTP of C-fiber-evoked field potentials in spinal dorsal horn was evaluated in urethan-anesthetized Sprague-Dawley rats. We found the following. 1) Spinal application of SKF 38393, a D1/D5 receptor agonist, induced a slowly developed LTP of C-fiber-evoked field potentials, lasting for >10 h, and the effect was blocked by the D1/D5 antagonist SCH 23390, whereas a D2 receptor agonist (quinpirole) induced depression of C-fiber responses, lasting for 2 h. 2) The potentiation produced by D1/D5 receptor agonist occluded the late phase but not the early phase of the spinal LTP produced by tetanic stimulation. 3) SCH 23390 selectively depressed the late-phase LTP, when applied 40 min before tetanic stimulation. 4) The D1/D5 agonist-induced potentiation is blocked by the protein synthesis inhibitor anisomycin. 5) Activation of protein kinase A by spinal application of 8-Br-cAMP also induced spinal LTP, and the action occluded the potentiation induced by the D1/D5 receptor agonist. These results suggest that the spinal D1/D5 receptors participate in the protein synthesis-dependent late-phase LTP of C-fiber-evoked field potentials in spinal dorsal horn through the cAMP signaling pathway.  相似文献   

13.
Long-term potentiation (LTP) of C-fiber-evoked field potentials in spinal dorsal horn may be relevant to hyperalgesia, an increased response to noxious stimulation. The mechanism underlying this form of synaptic plasticity is, however, still unclear. Considerable evidence has shown that calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase A (PKA), and protein kinase C (PKC) are important for LTP in hippocampus. In this study, the roles of these three protein kinases in the induction and maintenance of LTP of C-fiber-evoked field potentials were evaluated by application of specific inhibitors of CaMKII (KN-93 and AIP), PKA (Rp-CPT-cAMPS), and PKC (chelerythrine and G? 6983) at the recording segments before and after LTP induction in urethane-anesthetized Sprague-Dawley rats. We found both KN-93 and AIP, when applied at 30 min prior to tetanic stimulation, completely blocked LTP induction. At 30 min after LTP induction, KN-93 and AIP reversed LTP completely, and at 60 min after LTP induction, they depressed spinal LTP in most rats tested. Three hours after LTP induction, however, KN-93 or AIP did not affect the spinal LTP. Rp-CPT-cAMPS, chelerythrine, and G? 6983 blocked the spinal LTP when applied at 30 min before tetanic stimulation and reversed LTP completely at 15 min after LTP induction. In contrast, at 30 min after LTP induction, the drugs never affected the spinal LTP. These results suggest that activation of CaMKII, PKA, and PKC may be crucial for the induction and the early-phase but not for the late-phase maintenance of the spinal LTP.  相似文献   

14.
Long-term potentiation (LTP) involves a prolonged increase in neuronal excitability following repeated afferent input. This phenomenon has been extensively studied in the hippocampus as a model of learning and memory. Similar long-term increases in neuronal responses have been reported in the dorsal horn of the spinal cord following intense primary afferent stimulation. In these studies, we utilized the spinal cord slice preparation to examine effects of the potently antinociceptive mu opioids in modulating primary afferent/dorsal horn neurotransmission as well as LTP of such transmission. Transverse slices were made from the lumbar spinal cord of 10- to 17-day-old rats, placed in a recording chamber, and perfused with artificial cerebrospinal fluid also containing bicuculline (10 microM) and strychnine (1 microM). Primary afferent activation was achieved in the spinal slice by electrical stimulation of the dorsal root (DR) or the tract of Lissauer (LT) which is known to contain a high percentage of small diameter fibers likely to transmit nociception. Consistent with this anatomy, response latencies of LT-evoked field potentials in the dorsal horn were considerably slower than the response latencies of DR-evoked potentials. Only LT-evoked field potentials were found to be reliably inhibited by the mu opioid receptor agonist [D-Ala(2), N-Me-Phe(4), Gly(5)] enkephalin-ol (DAMGO, 1 microM), although evoked potentials from both DR and LT were blocked by the AMPA/kainate glutamate receptor antagonist 6-cyano-7-nitroquinoxalene-2,3-dione. Moreover repeated stimulation of LT produced LTP of LT- but not DR-evoked potentials. In contrast, repeated stimulation of DR showed no reliable LTP. LTP of LT-evoked potentials depended on N-methyl-D-aspartate (NMDA) receptor activity, in that it was attenuated by the NMDA antagonist APV. Moreover, such LTP was inhibited by DAMGO interfering with LTP induction mechanisms. Finally, in whole cell voltage-clamp studies of Lamina I neurons, DAMGO inhibited excitatory postsynaptic current (EPSC) response amplitudes from LT stimulation-evoked excitatory amino acid release but not from glutamate puffed onto the cell and increased paired-pulse facilitation of EPSCs evoked by LT stimulation. These studies suggest that mu opioids exert their inhibitory effects presynaptically, likely through the inhibition of glutamate release from primary afferent terminals, and thereby inhibit the induction of LTP in the spinal dorsal horn.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号