神经元和胶质细胞间功能联系的研究进展

神经元与胶质细胞间的信号包括离子流、神经递质、细胞粘附分子及特异的神经元突触和非突触区特异信号分子。通过释放神经递质及其他胞外信号分子，胶质细胞能影响神经元的兴奋性及突触传递，并在神经网络中调节神经活性。神经元与胶质细胞间的双向作用对轴突传导、突触传递及信息过程非常关键。本文综述了神经元与胶质细胞间功能联系的研究进展。     

胶质细胞在神经毒性中的作用

胶质细胞在神经毒性中的作用牛玉杰１刘毓谷神经组织由神经元和胶质细胞组成，神经元能够产生神经冲动并将神经冲动传递给其他神经元或效应细胞，对于调节机体各系统的功能以及学习记忆等过程具有重要意义。因此，传统的神经毒理学观点认为，外来化合物引起的神经毒性是神...     

神经胶质细胞在多发性硬化中的作用

多发性硬化是以炎性脱髓鞘病变为主要特征的中枢神经系统自身免疫性疾病。神经胶质细胞是中枢神经系统中除神经元外的另一大类细胞,目前研究证明神经胶质细胞在多发性硬化的炎性脱髓鞘过程中发挥了重要作用。本文对小胶质细胞、少突胶质细胞、星形胶质细胞在多发性硬化中的作用进行综述。     

小胶质细胞极化在帕金森病中的作用

帕金森病(PD)是一种高发于中高年人群的神经退行性疾病。近年来,小胶质细胞介导的神经炎症在PD的发病过程中受到了广泛的关注。越来越多的证据表明,炎症微环境会极大地影响小胶质细胞的表型变化,不同极化类型的小胶质细胞可分泌不同作用的炎症因子,介导神经炎症,与PD的发病过程密切相关,但目前其相关机制尚不明确。目前研究认为,调节具有神经毒性的M1型小胶质细胞和产生神经保护作用的M2型小胶质细胞之间的平衡对PD中多巴胺能神经元的损伤起到重要的神经保护作用。本文就小胶质细胞极化在PD发病过程中的作用及其关机制进行综述,为靶向调控小胶质细胞极化治疗PD提供了新的思路并奠定相关基础。     

卫星胶质细胞对外周神经元作用的研究进展

近年来的研究表明,神经胶质细胞在整个神经系统中发挥着极为重要的作用。和中枢神经系统中的星型胶质细胞相似,外周神经中的卫星胶质细胞参与了神经系统中的各种生理和病理过程,并且通过神经元与胶质细胞的相互作用,影响着神经元的功能。该文就卫星胶质细胞如何影响神经元的功能做一综述。     

神经胶质细胞作用的研究进展

以往研究多认为神经胶质细胞仅提供支持、营养、保护的作用,随着对胶质细胞膜离子通道、受体、第二信使的不断深入研究,被发现它含有大部分神经递质、神经肽、激素及神经营养因子受体、离子通道、神经活性氨基酸亲和载体、细胞识别分子等,并能分泌多种神经活性物质(生长因子、神经营养因子和细胞因子等),在神经系统正常生理及病理过程中具有重要作用。相信随着对神经胶质细胞的深入研究,将会有更多重要的发现,其意义重大。     

星型胶质细胞在脑缺血性疾病中的神经元保护机制

脑血管疾病是一类严重危害人类健康的疾病,其中缺血性脑卒中占脑血管疾病的50%～80%。近年来研究表明,星型胶质细胞可通过维持胞外K+平衡,清除氧自由基,对神经元提供神经营养因子、摄取过量兴奋性氨基酸、调节离子通道等方式对脑缺血性疾病中的神经元提供保护作用。该综述就近年来星型胶质细胞在脑缺血性疾病中的神经元保护相关机制进行了阐述。     

星形胶质细胞在脑缺血中的变化和作用

星形胶质细胞作为中枢神经系统数量最多的细胞,它在脑缺血中发生增殖、肥大,特异性标记物胶原纤维酸性蛋白和波形蛋白表达明显增加。星形胶质细胞在缺血状态下具有较强的耐受力,可通过多种途径保护神经元。并且它也通过产生兴奋性氨基酸、炎症介质,降低缝隙连接等损伤神经元。因此,星形胶质细胞在脑缺血中起着损伤和保护脑组织的双重作用。明确星形胶质细胞在脑缺血中的作用及其机制,可能将为脑缺血的治疗提供新的靶点。     

嘌呤受体信号通路在肺部疾病中的作用

嘌呤能G蛋白偶联受体是人体中表达较为丰富的一类G蛋白偶联受体.嘌呤能受体在心肺系统广泛分布,几乎所有肺实质和间质细胞中均存在多种受体亚型的表达,说明了嘌呤能信号系统在肺组织中发挥重要生理作用.本文重点阐述肺部疾病尤其是哮喘、急性肺损伤、囊性肺纤维化、远端肺动脉高压中嘌呤能受体的作用.     

神经胶质细胞与突触可塑性关系的研究进展

突触可塑性与神经系统的发育、损伤后修复等密切相关。神经胶质细胞通过能量物质传递、信号转导通 信等方面与神经元保持密切交流,是促进突触可塑性的重要途径。星形胶质细胞在形态上和功能上均与突触联系 密切,是调控突触可塑性的重要影响因素;小胶质细胞与突触进行双向信息交互,是发育和成年期突触可塑性的关 键调节因子;少突胶质细胞参与髓鞘形成,为突触传递提供代谢底物,是促进突触可塑性的潜在力量。就星形胶质 细胞、小胶质细胞以及少突胶质细胞与突触可塑性关系的相关研究进展进行综述,以期为深入认识神经胶质细胞与 突触可塑性的相互关系提供参考。     

Role of purinergic receptors in platelet-nanoparticle interactions

Primary objective. Elevation of the thrombotic responses mediated by a variety of carbon-derived nanoparticles was recently reported in the literature. In this paper our objective was to investigate whether metal nanoparticles (iron, copper, gold or cadmium sulfide [CdS]) impart such prothrombotic effects on human platelets. Secondly, we wanted to examine whether such effects were mediated through any specific platelet receptor. Experimental design. The size distributions and zeta potentials of characterized gold, copper, iron and CdS (rod & sphere) nanoparticles were measured using photon correlation spectroscopy and laser Doppler velocimetry. The effect of two classes of agonists, adenosine diphosphate (ADP) and epinephrine were studied. To study the effect of ADP, a suboptimal concentration was chosen below a critical concentration. Above the critical concentration, the aggregation assumed its standard hyperbolic shape (and de-aggregation disappeared). Pro-aggregatory action of a given agent can be understood with better sensitivity using a transition from deaggregation to aggregation at this suboptimal agonist level. For epinephrine at low concentration this criticality was absent, however the aggregatory profile showed a delayed response. Two classes of human subjects (a) normal and (b) individuals with acute coronary syndrome, who were under a therapeutic regime of clopidogrel were chosen, as clopidogrel is a specific inhibitor of the low affinity ADP receptor P2Y12. This enabled us to understand the pro-aggregatory effects of nanoparticles with only P2Y1 (high affinity ADP receptor) active. In another set of aggregation experiments, the inhibitor MRS2179 was used to specifically block the high affinity ADP receptor P2Y1. Methods. The threshold ADP concentration was determined using an ADP titration. Nanoparticle rich platelet suspensions were exposed to a previously determined sub-optimal ADP concentration. The experiment was repeated with iron, copper, gold and CdS nanoparticles (later with two different morphologies, rod and sphere). Results. The primary result was that the nanoparticles, composed of various materials and shape features, are likely to impart a pro-aggregatory response in platelets. That the pro-aggregatory effect is not solely a physical self-assembly process and has ADP dependence, is evident from the reversal of the said response by apyrase. The fact that the response was absent in the case of P2Y12 blocked subjects (CdS nanoparticles being an exception) suggests that the low-affinity P2Y12 receptor may be an important target for the nanoparticles. If on the other hand P2Y1 (the high affinity receptor) was blocked by the specific inhibitor MRS2179, nanoparticles could still induce higher aggregation in normal subjects. No significant nanoparticle induced proaggregatory effect was observed for epinephrine. Inference. It is inferred, that the said platelet effect is mediated through ADP receptors, the probable target being the low affinity purinergic receptor P2Y12. The indication is that P2Y12 is a potential target for a wide class of nanoparticles. However the extent of the induced pro-aggregatory effect may be dependent upon the constitutive material and/or the shape of the nanoparticles. This may have important implications in the use of nano-materials in human drug delivery systems. The fact that clopidogrel prevents this nanoparticle mediated prothrombotic effect (with CdS as an exception) may help making nanodrug administration safer.     

Pharmacological properties of ATP-sensitive purinergic receptors expressed in human G292 osteoblastic cells

We characterized the pharmacological properties of P2 receptors expressed in G292 osteoblastic cells by studying the responses or changes in intracellular Ca²⁺ level to P2 receptor agonists, antagonists and modulators. ATP induced robust responses in a concentration-dependent manner with EC₅₀ of 0.5 ± 0.07 μM. While α,β-methylene-ATP (αβmeATP) and 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP) were ineffective, ADP mimicked the action of ATP with EC₅₀ of 0.7 ± 0.2 μM. UTP and UDP also evoked responses with EC₅₀ of 2.0 ± 0.4 μM and 0.5 ± 0.1 μM respectively, but their responses were much smaller, resulting in an order of the response magnitude: ATP ~ ADP >> UTP ~ UDP. The responses evoked by ATP and ADP were blocked by pyridoxal-5'-phosphate-6-azophenyl-2,4,-disulfonate (PPADS) with IC₅₀ of 3.0 ± 0.05 μM and 5.0 ± 0.4 μM respectively, but not by suramin up to 30 μM. ATP-evoked responses were insensitive to inhibition by trinitrophenyl-ATP (TNP-ATP) and brilliant blue G. ADP-evoked responses were significantly inhibited by 2'-deoxy-N⁶-methyladenosine-3',5'-biphosphate (MRS2179) and 2-chloro-N⁶-methyl-(N)-methanocarba-2'-deoxyadenosine-3',5'-bisphosphate (MRS2279) with IC₅₀ of 48 ± 1.9 μM and 7.7 ± 0.9 μM respectively. Taken together, these results provide strong evidence for functional expression of ATP-sensitive P2Y receptors and particularly P2Y₁-like receptor in G292 cells.     

内分泌胰腺嘌呤受体研究的新进展

嘌呤受体分为腺苷作用的P1受体和ATP作用的P2受体两大类;P2受体又分为P2X(离子通道受体)和P2Y(G蛋白耦联受体)。多种嘌呤受体亚型表达于内分泌胰腺,并参与调节胰岛素的分泌。嘌呤受体和配体与糖尿病及其并发症的发病机制密切相关,并可能成为糖尿病及其并发症治疗的新靶点。     

Apoptotic cell death in neurons and glial cells: implications for Alzheimer's disease

It is now generally accepted that massive neuronal death due to oxidative stress is a common characteristic of brains in neurodegenerative diseases. Recently, numerous apoptosis-regulating factors and multiple pathways have been identified, and apoptotic cell death has been implicated in neuronal loss in Alzheimer's disease. Although glial cells are more resistant to oxidative stress than neurons, extensive oxidative stress seems to cause apoptotic cell death in glial cells. In fact, signs of apoptosis are observed in both neurons and glial cells in the brains of patients with Alzheimer's disease. This review summarizes current findings regarding apoptotic processes and discusses the possible involvement of apoptosis-regulating factors in the pathology of Alzheimer's disease.     

The roles of P2 purinergic receptors in nociception and antinociception

Extracellular adenosine 5‘-triphosphate (ATP) has been established as a neurotransmitter or neuromodulator in both the periphe- ral and central nervous systems,in addition to diverse intracellular roles of it.P2 purinergic receptors,the receptors of ATP,are classified into two subfamilites,ionotropic P2X and metabotropic P2Y receptors.Recent studies suggest that ATP play a significant role in facilitating perpheral and spinal nociceptive transmission via P2X receptors.However,we demonstrated that at the supraspinal level P2X receptor agonists produce an antinociception.On the other hand,the activation of some subtypes of P2Y receptors in the spinal cord caused inhibitory effects on nociceptive transmission.Thus,P2X and P2Y receptors are suggested to be related to diverse roles in nociceptive functions at peripheral,spinal and supraspinal levels.We would like to take an overview about the significance of P2X and P2Y receptors in nociception and antinociception.     

Vasodilating effects of etimizol in vitro and its relation to purinergic receptors

The paper is concerned with the effect of the breath analeptic agent etimizole on the smooth muscle of vessels under in vitro conditions from the viewpoint of its assumed interaction with purinergic receptors. Isolated preparations of the coronary artery and a. dorsalis pedis of the dog served as experimental material. Etimizole administered in a cumulative manner in dependence on concentration decreases the strength of contraction of the preparations contracted with K+ ions. This relaxant effect, similarly as the effect of adenosine, is not affected by a removal of the endothelium, can be inhibited with theophylline and potentiated with dipyridamole. Etimizole in higher concentrations inhibits the response of vascular preparations to electrical stimulation. In the concentration of 10(-4) mol.l-1 it potentiates the relaxant effect of adenosine, the experimental effects not differing from the theoretical curve for the addition of effects. The obtained results support the assumption that the vasodilating effect of etimizole is mediated prevalently by P1 purinergic receptors.     

Interaction of P2 purinergic receptors with cellular macromolecules

Ionotropic P2X and metabotropic P2Y receptors interact with a number of macromolecules in the cell membrane which may contribute to their functional plasticity. P2X receptors are homomeric or heteromeric assemblies of three subunits. P2Y receptors may form oligomeric complexes either with the same or with other P2Y receptor types. Although the signalling mechanism of P2X receptor channels is fast (within milliseconds) and relatively simple, by originating from the opening of an ion channel permeable to mono- and divalent cations, various macromolecules may modify the trafficking of these receptors to and from the cell membrane, as well as their activation and desensitization kinetics, and the possible opening of membrane pores induced by long-lasting exposure to agonists. P2X and Cys-loop receptors may physically interact with each other, resulting in mutual current occlusion. Heteromeric P2Y receptors may, via G_s, G_q/11 or G_i/o protein-coupling and activation of the respective transduction mechanisms, mediate responses in the range of a few seconds. However, P2Y receptors may also interact with the signalling cascade of, e.g. receptor tyrosine kinases, and thereby mediate responses on a much slower time scale (within hours to days). In addition, P2Y receptors may interact with small, homomeric G proteins, integrins, and PDZ proteins. Eventually, P2Y receptors may cross-talk via Gα-dependent signalling with other G protein-coupled receptors and via Gβγ (or indirectly Gα)-dependent signalling with various ion channels. Thus, the activation of P2X and P2Y receptors by extracellular adenosine triphosphate/adenosine diphosphate or uridine triphosphate/uridine diphosphate may trigger specific chains of events which interact at the level of the individual elements both with each other and with the transduction mechanisms of other receptors, creating a huge diversity of the possible effects.