Structural hybridization of pyrrolidine-based T-type calcium channel inhibitors and exploration of their analgesic effects in a neuropathic pain model

Highly effective and safe drugs for the treatment of neuropathic pain are urgently required and it was shown that blocking T-type calcium channels can be a promising strategy for drug development for neuropathic pain. We have developed pyrrolidine-based T-type calcium channel inhibitors by structural hybridization and subsequent assessment of in vitro activities against Ca_v3.1 and Ca_v3.2 channels. Profiling of in vitro ADME properties of compounds was also carried out. The representative compound 17h showed comparable in vivo efficacy to gabapentin in the SNL model, which indicates T-type calcium channel inhibitors can be developed as effective therapeutics for neuropathic pain.     

Forced expression of Phox2 homeodomain transcription factors induces a branchio-visceromotor axonal phenotype

What causes motor neurons to project into the periphery is not well understood. We here show that forced expression of the homeodomain protein Phox2b, shown previously to be necessary and sufficient for branchio-visceromotor neuron development, and of its paralogue Phox2a imposes a branchiomotor-like axonal phenotype in the spinal cord. Many Phox2-transfected neurons, whose axons would normally stay within the confines of the neural tube, now project into the periphery. Once outside the neural tube, a fraction of the ectopic axons join the spinal accessory nerve, a branchiomotor nerve which, as shown here, does not develop in the absence of Phox2b. Explant studies show that the axons of Phox2-transfected neurons need attractive cues to leave the neural tube and that their outgrowth is promoted by tissues, to which branchio-visceromotor fibers normally grow. Hence, Phox2 expression is a key step in determining the peripheral axonal phenotype and thus the decision to stay within the neural tube or to project out of it.     

大鼠坐骨神经结扎后脊髓钙结合蛋白PV的表达变化

目的:研究大鼠坐骨神经结扎模型钙结合蛋白Parvalbumin(PV)在脊髓的时空变化规律,为探讨其在神经再生中的作用与机制提供实验依据。方法:SD大鼠随机分为假手术对照组和坐骨神经结扎组,实验组结扎后分别存活1,3,7,14或21d,采用免疫组化结合图像分析技术观察PV在脊髓的表达变化。结果:在对照组,PV免疫阳性神经元主要分布于腰髓背角Ⅱ层,Ⅲ～Ⅵ层只观察到少量散在分布的PV样阳性神经元,脊髓前角Ⅷ层和Ⅸ层内也可见少量多极的大型阳性神经元。术后各时间点PV样阳性神经元表达下降,14d下降最显著,21d表达有所上升,但还是低于7d组。脊髓后角PV免疫阳性产物灰度值测定结果显示:术后14d后角PV表达最低,与对侧和对照组以及1、3d组相比有统计学意义(P<0.05)。结论:坐骨神经结扎后PV表达变化呈现一定的时空模式,为进一步揭示PV在神经系统疾病中的作用提供实验依据。     

脊髓外科手术术后精神障碍患者发病影响因素及抑制性神经递质水平、神经营养因子表达变化情况分析

摘要 目的：探讨与分析脊髓外科手术术后精神障碍患者发病影响因素及抑制性神经递质水平、神经营养因子表达变化情况。方法：选择2016年9月到2021年5月本院完成脊髓外科手术的患者83例作为研究对象,检测血清抑制性神经递质水平、神经营养因子（NTFs）表达水平。所有患者都给予抑郁自评量表（SDS）调查、执行功能行为评定量表成人版自评问卷（BRIEF-A）评分并进行相关性分析。结果：83例患者术后平均SDS评分为45.10±2.87分,判定为精神障碍23例（精神障碍组）,占比27.7 %。精神障碍组的性别、年龄、手术时间、术中出血量与非精神障碍组对比无差异（P>0.05）,精神障碍组的饮酒、术后清醒时间与非精神障碍组对比有差异（P<0.05）。精神障碍组的BRI自我控制、情感控制、转移、抑制等评分与MI任务启动、任务监督、工作记忆、计划、组织评分都高于非精神障碍组（P<0.05）。精神障碍组的血清NTFs含量低于非精神障碍组,血清HA与5-HT含量高于非精神障碍组（P<0.05）。在83例患者中,Pearson分析显示SDS评分与饮酒、术后清醒时间、血清NTFs、NA、5-HT含量都存在相关性（P<0.05）;二分类logistic逐步回归显示术后清醒时间、血清NTFs、NA、5-HT含量都为导致脊髓外科手术术后精神障碍患者发病的重要因素（P<0.05）。结论：脊髓外科手术术后精神障碍的发生较常见,可导致患者认知与执行功能降低,多伴随有抑制性神经递质水平表达上升与神经营养因子表达下降,血清NTFs、NE、5-HT含量都为导致精神障碍发病的重要因素。     

大鼠颈段脊髓灰质板层及其细胞构筑

取12只SD(Sprague-Dawley)大鼠颈段脊髓横断面冰冻切片,用焦油紫和Pal-Weigert染色法染色,光镜观察SD大鼠颈段脊髓的组织结构,对SD大鼠脊髓灰质板层的细胞构筑进行研究。结果显示,Ⅰ层边界呈长弧形,Ⅰ、Ⅱ、Ⅲ、Ⅳ层呈层叠状排列,细胞多为椭圆形。Ⅴ、Ⅵ层均可分为内侧部和外侧部,外侧部分布大型细胞,Ⅴ层内侧部以中型椭圆形、三角形细胞为主,Ⅵ层内侧部以中型梭形细胞为主。Ⅶ层位于中间带,C5-C7Ⅶ层向前角延伸和Ⅷ层一起占据前角大部,Ⅶ及Ⅷ层的中型和大型细胞呈集中分布。Ⅷ层在C1-C4及C8占前角大部,在C5-C7位于前角内侧部。Ⅸ层主要由含大型运动神经元的核团组成。Ⅹ层由中型梭形细胞和小型星状细胞组成。对比观察发现,SD大鼠脊髓颈段板层类似于猫的Rexed分层,但灰质轮廓、板层出现节段、板层形态及其变化等方面均有所不同。     

ERK 1,2 and p38 pathways are involved in the proliferative stimuli mediated by urokinase in osteoblastic SaOS-2 cell line

Bone metastases from prostate origin generate an osteoblastic reaction that is expressed in vitro by increased osteoblast proliferation. The urokinase-like plasminogen activator (u-PA) present in the media conditioned by tumoral prostatic cells acting as a ligand of the cellular membrane receptor (u-PAR), has been identified as the specific factor that modulates this proliferative reaction. The present study represents an effort to unravel the intracellular pathway by which u-PA activates osteoblastic proliferation and to evaluate the role of cellular receptor u-PAR in this proliferative phenomenon. Our results show that in vitro u-PA stimulates proliferation of SaOS-2 osteoblastic cells by activating the MAP kinase route of ERK 1 and 2 and the p38 pathway. These results are in accordance with the inhibition of intermediate activation and cell proliferation by PD 098059 and SB 203580, specific inhibitors of MEK and p38, respectively. We also show that SaOS-2 cells increase their proliferative response when cells are plated onto vitronectin, the second natural ligand of u-PAR, and that culturing SaOS-2 cells in the presence of u-PA represents a stimuli for u-PAR expression. On the basis of these results we propose that osteoblastic cells respond to the prostate-derived u-PA stimuli in a very efficient manner that includes the utilization of two different signaling routes and the stimulation of the expression of the u-PA receptor.     

Excitatory action of lead on rat sympathetic preganglionic neurons in vitro and in vivo

Lead exposure elicited an increase in blood pressure and was considered to be a cardiovascular risk factor. The involvements of sympathetic nervous system and circulating catecholamines have been implicated in lead-induced hypertension. This study examined the effects of PbCl(2) on sympathetic preganglionic neurons (SPNs) in vitro and in vivo. In vitro electrophysiological study showed that superfusion of a low concentration (5 microM) of PbCl(2), which had no effects on membrane potential and spontaneous discharge rate, enhanced excitatory postsynaptic potentials (EPSPs) in some of the SPNs examined but inhibited inhibitory postsynaptic potentials (IPSPs) in other SPNs tested. A higher concentration (50 microM) of PbCl(2) inhibited both EPSPs and IPSPs in all SPNs examined. In vivo study showed that intrathecal injection of PbCl(2) (10 and 100 nmol) via an implanted cannula to the T7-T9 segments of urethane-anesthetized rats increased both the heart rate and mean arterial pressure. The pressor and tachycardic responses of intrathecal PbCl(2) (100 nmol) were attenuated by pretreatment with intravenous administration of hexamethonium (10 mg/kg) or intrathecal AP-5 (DL-2-amino-5-phosphonovaleric acid, 100 nmol), but were not significantly antagonized by prior intrathecal administration of CNQX (6-cyano-7-nitroquinoxaline-2,3-dione, 100 nmol). Taken together, these results demonstrated that lead may exert a stimulatory effect on SPNs, which may result from the enhancement of EPSPs and inhibition of IPSPs by low concentrations of lead.     

Topical application of dynorphin A (1-17) antiserum attenuates trauma induced alterations in spinal cord evoked potentials,microvascular permeability disturbances,edema formation and cell injury: an experimental study in the rat using electrophysiological and morphological approaches

Summary.  Dynorphin is a neuropeptide that is present in high quantities in the dorsal horn of the spinal cord. The peptide is actively involved in pain processing pathways. However, its involvement in spinal cord injury is not well known. Alteration in dynorphin immunoreactivity occurs following a focal trauma to the rat spinal cord. Infusion of dynorphin into the intrathecal space of the cord results in ischemia, cell damage and abnormal motor function. Antibodies to dynorphin when injected into the intrathecal space of the spinal cord following trauma improve motor recovery, reduce edema and cell changes. However, influence of dynorphin on trauma induced alteration in spinal cord bioelectrical activity is still not known. Spinal cord evoked potentials (SCEP) are good indicator of spinal cord pathology following trauma. Therefore, in present investigation, influence of dynorphin antibodies on trauma induced changes in SCEP were examined in our rat model. In addition, spinal cord edema formation, microvascular permeability disturbances and cell injury were also investigated. Our results show that topical application of dynorphin antiserum (1 : 200) two min before injury markedly attenuated the SCEP changes immediately after injury. In the antiserum treated animals, a significant reduction in the microvascular permeability, edema formation and cell injury was observed in the traumatised spinal cord. These observations suggest that (i) dynorphin is involved in the altered bioelectrical activity of the spinal cord following trauma, (ii) the peptide actively participates in the pathophysiological processes of cell injury in the spinal cord trauma, and (iii) the dynorphin antiserum has potential therapeutic value for the treatment of spinal cord injuries. Received July 3, 2001 Accepted August 6, 2001 Published online July 31, 2002