石菖蒲抗癫痫作用及其机制的研究进展

癫痫是最常见的神经系统疾病之一,发病率逐年增加,目前其主要治疗手段是药物治疗,但是效果有限。石菖蒲具有开心窍、益心智、安心神等功效,是祖国医学治疗癫痫症的常用味药;石菖蒲的多种提取物及其有效成分α-细辛醚具有抗癫痫作用,在癫痫的多种发病机制中发挥了降低神经兴奋性、保护神经元等作用。同时,石菖蒲对神经系统还具有兴奋性和抑制性双向调节作用。本文主要综述了目前癫痫发病机制的研究进展,在此基础上探讨中药石菖蒲的抗癫痫作用及其可能的作用靶点,论述其发展为辅助抗癫痫药物的可能性。     

盐酸苯环壬酯对最大电休克发作及戊四氮惊厥模型的抗惊作用

目的评价盐酸苯环壬酯抗癫痫疗效，探讨其抗癫痫作用机制。方法建立不同癫痫发作模型，评价盐酸苯环壬酯等药物抗癫痫疗效；观察盐酸苯环壬酯等药物对致死剂量NMDA中毒小鼠、NMDA诱导的原代培养大鼠海马神经细胞损伤及NMDA诱发电流的影响。结果盐酸苯环壬酯在不同癫痫发作模型上均具明显抗惊作用；并可显著对抗致死剂量NMDA中毒，浓度依赖性抑制NMDA诱导原代培养大鼠海马神经细胞损伤及NMDA诱发电流。结论盐酸苯环壬酯在经典癫痫模型上均具显著抗惊作用，其作用机制可能与其对NMDA受体的拮抗作用有关。     

左乙拉西坦——一种具有全新作用机制的抗癫痫新药

左乙拉西坦是一种新型的口服抗癫痫药物,与其他抗癫痫药物的结构不同,具有全新的抗癫痫机制。左乙拉西坦的确切抗癫痫机制尚不明,但与传统抗癫痫药物作用于离子通道或兴奋性、抑制性神经递质系统不同。左乙拉西坦几乎具备了较好的抗癫痫药物的所有药动学特性:生物利用度高、线性曲线、低蛋白结合率、无肝酶诱导作用。多种动物模型显示左乙拉西坦具有抗癫痫特性。全球范围的3个重要多中心、随机、双盲、安慰剂对照临床试验结果显示左乙拉西坦具有确切的抗癫痫疗效和很好的耐受性,可用于治疗癫痫、神经痛和其他神经系统疾病。     

大鼠海马注射胍基琥珀酸引起的惊厥及对神经细胞的损害作用

大鼠海马注射微量胍基琥珀酸,可引起典型的阵挛性惊厥和癫痫样放电,用高倍显微镜进行组织学分析发现,胍基琥珀酸能广泛损伤大鼠注射侧海马CA₁部位的锥体细胞。典型的抗癫痫药苯巴比妥和苯妥英钠不能对抗上述作用,而非竞争性NMDA受体的拮抗剂氯胺酮却有对抗作用,且能预防其对海马神经细胞的损害。结果提示,胍基琥珀酸在诱发惊厥和对神经细胞的损伤方面与兴奋性氨基酸 谷氨酸的作用非常相似。同时也说明,其作用与NMDA受体有一定的关系。     

儿童抗癫痫药物研究进展

目前,使用抗癫痫药物仍然是儿童癫痫治疗主要手段. 由于儿童处于快速生长发育阶段,其机体器官功能、药动学与成人显著不同,且选药、疗效评估、预后具有特殊性. 较成人而言,儿童由于大脑兴奋性和抑制性尚未达到平衡,更易罹患癫痫,且抗癫痫药物不合理使用也更易发生认知功能障碍. 如何合理应用抗癫痫药物,达到满意的治疗效果,已经引起广大医务工作者的广泛注意. 因此,不仅要遵循抗癫痫药物治疗原则选药、对患者进行定期疗效评估,还必须尽可能选择对认知功能损害小的抗癫痫药物,积极检测不良反应,这对儿童癫痫药物治疗具有重要意义.     

脑缺血非炎症损伤机制的研究进展

据世界卫生组织对57个国家的调查 ,脑缺血疾病病死率仅次于癌症和心肌梗死 ,脑缺血是脑血管疾病中最常见的一种临床类型 ,其对脑组织的损害涉及脑组织能量代谢障碍、炎症反应、兴奋性氨基酸毒性效应、自由基损伤、钙离子超载、神经细胞凋亡、神经肽含量比例失调等多个方面。鉴于脑缺血时能量代谢障碍与炎症损伤机制研究较成熟 ,现就脑缺血时非炎症损伤机制作一综述。1兴奋性氨基酸的神经毒性效应兴奋性氨基酸 (EAA)是中枢神经系统中的兴奋性神经递质 ,包括谷氨酸 (Glu)和天门冬氨酸 (Asp) ,在生理条件下 ,它们参与许多生理功能 ,从感觉信…     

中药多糖治疗神经退行性疾病及其机制

目前,神经退行性疾病的发病率逐年增加,临床上使用的药物只能改善患者的症状,不能阻止疾病进程,综合调治、多靶点发挥作用是中药的特点和优势。多糖是许多中药的有效成分之一,对神经相关疾病具有良好的防治和改善作用。有关神经退行性疾病的发病机制尚不清楚,相关假说可能与细胞凋亡、氧化应激、兴奋毒性有关。(1)抑制细胞凋亡:神经细胞凋亡是神经系统疾病神经损伤的关键病理改变,多糖能增强神经细胞活力,减轻细胞核形态的改变及DNA断裂,从而抑制细胞凋亡。(2)抗氧化应激损伤:体内脂质过氧化造成DNA氧损伤,断裂,核酸及蛋白质破坏,基因突变,神经细胞凋亡,进而造成多种神经病变。多糖能够降低凋亡基因及蛋白的产生,上调Bc1-2/Bax比例,减少细胞凋亡。(3)抑制兴奋毒性:兴奋毒性是兴奋性神经递质-谷氨酸受体的过度持续活化而导致的神经元的死亡过程。多糖能降低脑组织和血清中兴奋性氨基酸含量,进而缓解神经元的进一步损伤。综上所述,多糖能够有效治疗和改善多种神经相关病症,其神经保护机制涉及抗氧化损伤、抑制细胞凋亡及兴奋性毒性等方面。中药多糖在医药和保健品领域蕴含着巨大的开发潜力。     

吗啡增强谷氨酸单钠神经毒性及其作用机制

用皮层神经细胞体外培养、形态学观察、单个神经细胞内游离钙检测及乳酸脱氢酶(LDH)测定等方法,观察了吗啡对谷氨酸单钠(MSG)神经毒性增强作用以及纳洛酮对吗啡作用的逆转,分析了其可能的作用机制。结果表明:吗啡能显著增强的MSG的细胞毒作用.纳络酮可逆转这种增强作用,细胞内Ca²⁺超载可能是兴奋性神经毒素引起神经元死亡的共同病理学机制。     

丙戊酸钠治疗儿童癫痫的血药浓度监测结果分析

<正>丙戊酸钠(sodium valproate,VPA)为一线的广谱抗癫痫药,通过增加脑内抑制性神经递质γ-氨基丁酸的含量来降低神经元兴奋性,起稳定神经元膜的作用[1],由于VPA的药代动力学及药效学个体差异较大,导致其剂量与血药浓度之间的相关性较差,血药浓度波动较大,剂量难以掌握。因此,监测其血药浓度是进行抗癫痫个体化治疗的必要手段[2]。     

兴奋性氨基酸转运体研究进展

兴奋性氨基酸转运体 (EAAT)位于突触前膜、突触囊泡和神经胶质细胞膜上。它们对于兴奋性氨基酸的再循环 ,兴奋性信号的终止以及保护神经细胞免受兴奋性毒性损害具有特别重要的意义。本文介绍EAAT研究进展     

Ketamine inhibits aerobic glycolysis in colorectal cancer cells by blocking the NMDA receptor-CaMK II-c-Myc pathway

Aerobic glycolysis plays a crucial role in cancer progression. Ketamine is often used for cancer pain relief in clinical settings. Moreover, ketamine inhibits proliferation and induces apoptosis in many cancer cell types. However, the anti-tumour mechanism of ketamine is still poorly understood. In the present study, we survey whether and how ketamine inhibits aerobic glycolysis in colon cancer cells. Glycolysis of colon cancer cells was determined by detecting the extracellular acidification rate in HT29 and SW480 cells. Quantitative real-time PCR was employed to determine mRNA expression. Calcium levels were detected with a Fluo-3 AM fluorescence kit. Micro-positron emission tomography/computed tomography (microPET/CT) imaging was employed to assess glycolysis in the tumours of the xenograft model. Ketamine treatment inhibited colon cancer cell viability and migration in HT29 and SW480 cells. Moreover, ketamine decreased aerobic glycolysis and decreased the expression of glycolysis-related proteins in HT29 and SW480 cells. MicroPET/CT demonstrated that ketamine decreased 18F-FDG uptake in the xenograft model. In addition, ketamine inhibited c-Myc expression and CaMK II phosphorylation and decreased calcium levels. Further, dizocilpine (an NMDAR inhibitor), and KN93 (a CaMK II inhibitor), decreased CaMK II phosphorylation, c-Myc expression, and cancer cell glycolysis; these results were similar to those with ketamine treatment. Furthermore, the anti-tumour effect of ketamine was counteracted by rapastinel (an NMDAR activator). Ketamine inhibited aerobic glycolysis in colon cancer cells probably by blocking the NMDA receptor-CaMK II-c-Myc pathway, thus attenuating colon cancer cell viability and migration.     

Targeting tumor glycolysis by a mitotropic agent

Metabolic reprogramming is one of the hallmarks of cancer. Altered metabolism in cancer cells is exemplified by enhanced glucose utilization, a biochemical signature that is clinically exploited for cancer diagnosis using positron-emission tomography and computed tomography imaging. Accordingly, disrupting the glucose metabolism of cancer cells has been contemplated as a potential therapeutic strategy against cancer. Experimental evidences indicate that targeting glucose metabolism by inhibition of glycolysis or oxidative phosphorylation promotes anticancer effects. Yet, successful clinical translation of antimetabolites or energy blockers to treat cancer remains a challenge, primarily due to lack of efficacy and/or systemic toxicity. Recently, using nanotechnology, Marrache and Dhar have documented the feasibility of delivering a glycolytic inhibitor through triphenylphosphonium (TPP), a mitotropic agent that selectively targets mitochondria based on membrane potential. Furthermore, by utilizing gold nanoparticles the investigators also demonstrated the potential for simultaneous induction of photothermal therapy, thus facilitating an additional line of attack on cancer cells. The report establishes that specific inhibition of tumor glycolysis is achievable through TPP-dependent selective targeting of cancer cells. This nanotechnological approach involving TPP-guided selective delivery of an antiglycolytic agent complemented with photothermal therapy provides a new window of opportunity for effective and specific targeting of tumor glycolysis.     

Effect of sorafenib on the energy metabolism of hepatocellular carcinoma cells

Recent data demonstrated that sorafenib impaired the oxidative phosphorylation of a rat myogenic cell line and suggested that this biochemical lesion can contribute to the cardiac toxicity caused by the drug. With the experiments reported here, we verified whether sorafenib inhibits oxidative phosphorylation also in cells from human hepatocellular carcinomas (HCCs), which are treated with this drug. By using the HCC cell lines PLC/PRF/5 and SNU-449 we studied the effects of the drug on ATP cellular levels, oxygen consumption and aerobic glycolysis, a metabolic pathway generally used by neoplastic cells to meet their energy demand. The effect of sorafenib on ATP cellular levels was also studied in cells grown in a glucose-free medium, which only derive their energy from oxidative phosphorylation. We found that at clinically relevant concentrations sorafenib hindered oxidative phosphorylation, whereas at the same time stimulated aerobic glycolysis in glucose-grown cells, thus attenuating the cellular ATP depletion. These results support the impairment of oxidative phosphorylation as a mechanism contributing to the antineoplastic activity of sorafenib in the treatment of HCCs.     

Inhibition of AXL enhances chemosensitivity of human ovarian cancer cells to cisplatin via decreasing glycolysis

Anexelekto (AXL), a member of the TYRO3-AXL-MER (TAM) family of receptor tyrosine kinases (RTK), is overexpressed in varieties of tumor tissues and promotes tumor development by regulating cell proliferation, migration and invasion. In this study, we investigated the role of AXL in regulating glycolysis in human ovarian cancer (OvCa) cells. We showed that the expression of AXL mRNA and protein was significantly higher in OvCa tissue than that in normal ovarian epithelial tissue. In human OvCa cell lines suppression of AXL significantly inhibited cell proliferation, and increased the sensitivity of OvCa cells to cisplatin, which also proved by nude mice tumor formation experiment. KEGG analysis showed that AXL was significantly enriched in the glycolysis pathways of cancer. Changes in AXL expression in OvCa cells affect tumor glycolysis. We demonstrated that the promotion effect of AXL on glycolysis was mediated by phosphorylating the M2 isoform of pyruvate kinase (PKM2) at Y105. AXL expression was significantly higher in cisplatin-resistant OvCa cells A2780/DDP compared with the parental A2780 cells. Inhibition of AXL decreased the level of glycolysis in A2780/DDP cells, and increased the cytotoxicity of cisplatin against A2780/DDP cells, suggesting that AXL-mediated glycolysis was associated with cisplatin resistance in OvCa. In conclusion, this study demonstrates for the first time that AXL is involved in the regulation of the Warburg effect. Our results not only highlight the clinical value of targeting AXL, but also provide theoretical basis for the combination of AXL inhibitor and cisplatin in the treatment of OvCa.     

Effects of GYKI 52466 and some 2,3-benzodiazepine derivatives on hippocampal in vitro basal neuronal excitability and 4-aminopyridine epileptic activity

In order to determine whether the anticonvulsant effect of 2, 3-benzodiazepines is also displayed in a model of in vitro epilepsy, such as the "epileptiform" hippocampal slice, we studied the effects of 2,3-benzodiazepine 1-(4-aminophenyl)-4-methyl-7, 8-methylenedioxe-5H 2,3-benzodiazepine hydrochloride (GYKI 52466) and some new 2,3-benzodiazepine derivatives on CA1 basal neuronal excitability and on CA1 epileptiform burst activity produced by 4-aminopyridine in rat hippocampal slices. The results showed that GYKI 52466 affected basal neuronal excitability as evidenced by its influence on the magnitude of the CA1 orthodromic-evoked field potentials. 2,3-Benzodiazepines showed their antiepileptic effect also in an in vitro model of experimental epilepsy. The effects of the new 2,3-benzodiazepine derivatives suggest that the methylenedioxidation in positions 7 and 8 of the 2,3-benzodiazepine ring is the main structural modification for the antiepileptic effect of 2,3-benzodiazepines to take place.     

METABOLIC BASIS OF CATECHOLAMINE-INDUCED WATER TRANSPORT IN EVERTED GUT SACS OF MOUSE

1. Catecholamine-induced water transport was measured using an everted gut sac technique. Adrenaline, noradrenaline and isoprenaline induce dose-dependent increases in water transport by the proximal intestinal sacs. Use of selective adrenergic agents revealed the possible involvement of alpha 1- and beta 2-receptors in mediation of catecholamine stimulation of water transport in this segment. 2. Inhibition of glycolysis reduced the effect mediated through alpha 1-receptors, while the inhibition of oxidative phosphorylation blocked the beta 2-receptor mediated increase in water transport. 3. Basal transport of water was also significantly reduced by inhibition of glycolysis but was significantly elevated by blockage of oxidative phosphorylation. 4. Suppression or stimulation of glycolysis was paralleled by similar changes in lactic acid release from the gut wall. 5. It is concluded that the energy for the catecholamine-induced water transport is contributed by glycolysis and oxidative phosphorylation coupled to alpha 1- and beta 2-receptors, respectively. Under basal conditions water transport is mainly dependent on glycolysis in the segment of intestine examined.     

Increased drug resistance is associated with reduced glucose levels and an enhanced glycolysis phenotype

BACKGROUND AND PURPOSE

The testing of anticancer compounds in vitro is usually performed in hyperglycaemic cell cultures, although many tumours and their in vivo microenvironments are hypoglycaemic. Here, we have assessed, in cultures of tumour cells, the effects of reduced glucose levels on resistance to anticancer drugs and investigated the underlying cellular mechanisms.

EXPERIMENTAL APPROACH

PIK3CA mutant (AGS, HGC27), and wild-type (MKN45, NUGC4) gastric cancer cells were cultured in high-glucose (HG, 25 mM) or low-glucose (LG, 5 mM) media and tested for sensitivity to two cytotoxic compounds, 5-fluorouracil (5-FU) and carboplatin, the PI3K/mTOR inhibitor, PI103 and the mTOR inhibitor, Ku-0063794.

KEY RESULTS

All cells had increased resistance to 5-FU and carboplatin when cultured in LG compared with HG conditions despite having similar growth and cell cycle characteristics. On treatment with PI103 or Ku-0063794, only the PIK3CA mutant cells displayed increased resistance in LG conditions. The PIK3CA mutant LG cells had selectively increased p-mTOR, p-S6, p-4EBP1, GLUT1 and lactate production, and reduced reactive oxygen species, consistent with increased glycolysis. Combination analysis indicated PI103 and Ku-0063794 were synergistic in PIK3CA mutant LG cells only. Synergism was accompanied by reduced mTOR signalling and increased autophagy.

CONCLUSIONS AND IMPLICATIONS

Hypoglycaemia increased resistance to cytotoxic agents, especially in tumour cells with a high dependence on glycolysis. Dual inhibition of the PI3K/mTOR pathway may be able to attenuate such hypoglycaemia-associated resistance.     

Deoxyelephantopin decreases the release of inflammatory cytokines in macrophage associated with attenuation of aerobic glycolysis via modulation of PKM2

Growing evidence suggests that activated immune cells undergo metabolic reprogramming in the regulation of the innate inflammatory response. Remarkably, macrophages activated by lipopolysaccharide (LPS) induce a switch from oxidative phosphorylation to aerobic glycolysis, and consequently results in release of proinflammatory cytokines. Pyruvate Kinase M2 (PKM2) plays a vital role in the process of macrophage activation, promoting the inflammatory response in sepsis and septic shock. Deoxyelephantopin (DET), a naturally occurring sesquiterpene lactone from Elephantopus scaber, has been shown to counteracts inflammation during fulminant hepatitis progression, but the underlying mechanism remains unclear. Here, we studied the function of the DET on macrophage activation and investigated the anti-inflammatory effects of DET associated with interfering with glycolysis in macrophage. Our results first demonstrated that DET attenuates LPS-induced interleukin-1β (IL-1β) and high-mobility group box 1 (HMGB1) release in vitro and in vivo and protected mice against lethal endotoxemia. Furthermore, DET decreased the expression of pyruvate dehydrogenase kinase 1 (PDK1), glucose transporter 1(GLUT1), lactate dehydrogenase A (LDHA), and reduced lactate production dose-dependently in macrophages. Moreover, we further revealed that DET attenuates aerobic glycolysis in macrophages associated with regulating the nuclear localization of PKM2. Our results provided a novel mechanism for DET suppression of macrophages activation implicated in anti-inflammatory therapy.     

Cell type specificity of GABA(A) receptor mediated signaling in the hippocampus

Inhibitory signaling mediated by ionotropic GABA(1) receptors generally acts as a major brake against excessive excitability in the brain. This is especially relevant in epilepsy-prone structures such as the hippocampus, in which GABA(A) receptor mediated inhibition is critical in suppressing epileptiform activity. Indeed, potentiating GABA(A) receptor mediated signaling is an important target for antiepileptic drug therapy. GABA(A) receptor mediated inhibition has different roles in the network dependent on the target neuron. Inhibiting principal cells will thus reduce network excitability, whilst inhibiting interneurons will increase network excitability; GABAergic therapeutic agents do not distinguish between these two alternatives, which may explain why, on occasion, GABAergic antiepileptic drugs can be proconvulsant. The importance of the target-cell for the effect of neuroactive drugs has emerged from a number of recent studies. Immunocytochemical data have suggested non-uniform distribution of GABA(A) receptor subunits among hippocampal interneurons and pyramidal cells. This has been confirmed by subsequent electropharmacological data. These have demonstrated that compounds which act on GABA(A) receptors or the extracellular GABA concentration can have distinct effects in different neuronal populations. Recently, it has also been discovered that presynaptic glutamate heteroreceptors can modulate GABA release in the hippocampus in a postsynaptic cell-specific manner. Since systemically administrated drugs may act on different neuronal subtypes, they can exhibit paradoxical effects. Distinguishing compounds that have target specific effects on GABAergic signaling may lead to novel and more effective treatments against epilepsy.