不同物理因子对红细胞作用的研究现状与展望

红细胞承担着对人体全身器官运输氧气和养分的功能，对维持人的生命活动至关重要，物理因子——激光、电场、磁场、电磁场和温度对血液尤其是红细胞有着重要的作用和影响，尽管物理因子对红细胞的作用研究有了一定的成果，但是仍存在相当大的局限性，其作用机制尚不完全明确。膜片钳技术已成为现在细胞电生理研究的有力手段．利用其研究物理因子对红细胞的作用与影响，将会为我们揭示更全面、更深入的的机理。     

兔颈上神经节神经元的急性分离及其通道电流记录

目的 探讨兔颈上神经节神经元分离及电生理研究的方法.方法 为了获得适用于膜片钳实验技术的单个颈上神经节神经细胞,应用酶和机械分离相结合的方法,急性分离20～30 d幼兔的单个颈上神经节神经元.通过倒置显微镜直接观察以及全细胞膜片钳技术的电压钳和电流钳分别对分离得到的颈上神经节神经元的形态学和电生理学特性进行研究.结果 急性分离所得活性较好的颈上神经节神经元胞体具有圆形和顶树突特征,立体感强,光晕明显.在全细胞膜片钳记录模式下可记录到全细胞电流、钠电流、钾电流及动作电位.结论 该方法可以得到形态和生理特性良好的单个颈上神经节神经元;该方法适用于膜片钳技术的研究,对深入探讨药物、物理因子等对神经节神经元离子通道的影响具有重要的应用价值.     

磁场生物效应的研究现状与展望

电磁辐射对人类健康可能的影响日益引起人们的关注,电磁场的生物学效应得到全世界的广泛研究.研究的目的不同,采用的实验手段不同,得到的结论也各有侧重.文中着重介绍了磁场在神经系统、离子通道电特性、血液循环和促骨再生等方面的生物效应的研究现状,并指出在磁场对细胞的作用机制上尚不完全明确,成为研究的热点.目的:提出了磁场生物效应研究的必要性和膜片钳应用于磁场生物效应研究的可行性.方法:阅读大量的国内外相关文献,并做相应的总结分析.结果:总结了磁场生物效应的机理和近年来研究现状,并提出了前景展望.结论:磁场生物效应研究虽然很多,但结果并不完全一致.膜片钳技术已成为细胞电生理研究的有利手段,将其应用于磁场对细胞的作用和影响,将可能会提供更全面、更准确的实验数据.     

SCN9A基因研究进展

SCN9A基因编码电压门控钠离子通道α-亚单位第Ⅸ型,主要在周围神经系统的感觉和交感神经表达,在背根神经节高表达.2004年我国学者杨勇等证明SCN9A是原发性红斑性肢痛症的致病基因,后来又有研究表明SCN9A是阵发性剧痛症、先天性无痛觉症的致病基因,SCN9A基因的致病机制及其与痛觉的关系逐渐成为科研热点,国内外学者在基于膜片钳技术的分子水平和基因敲除技术的整体水平都做了大量研究,本文对其研究进展作一概述.     

大鼠细动脉平滑肌细胞内酸中毒对ATP敏感钾通道的影响

目的：研究细胞内酸中毒对细动脉平滑肌细胞膜ＫＡＴＰ通道的影响。方法：应用膜片钳技术的内面向外式记录酶性分离的细动脉平滑肌上ＫＡＴＰ通道。结果；当细胞内无ＡＴＰ时，细胞内酸中毒降低通道电导，通道平均开放时间和开放时间长成分有所增大，对通道开放概率无明显影响；     

天花粉蛋白对人PBMC分泌细胞因子水平及离子通道的影响

目的：研究天花粉蛋白对正常人外周血单个核细胞（PBMC）分泌细胞因子水平及其对T淋巴细胞离子通道的影响，揭示其免疫调节作用机理。方法：用放射免疫分析法检测天花粉蛋白对PBMC在植物血浆素－M（PHA－M）刺激下分泌IL－2，IL－6水平的影响，用膜片钳技术检测天花粉蛋白对T淋巴细胞膜电压依赖性钾通道的影响，结果：天花粉蛋白促进正常人PBMC在PHA－M刺激下分泌IL－2和IL－6，增大TI林巴细胞膜电压依赖性钾通道的电流强度。结论：天花粉蛋白可通过增大T淋巴细胞膜上电压依赖性钾通道电流强度及促进PBMC分泌IL－2和IL－6，增强机体免疫功能。     

MDCK细胞Kca鉴定及粉防己碱（Tet）对MDCK细胞Kca的影响

目的：MDCK细胞KCA鉴定及探讨Tet对该通道的影响。方法：①利用膜片钳单通道记录技术，在inside-out膜片上，利用更换浴液中[K^ ]和[Ca^2 ]的方法对通道进行鉴定；②Inside-out膜片上，记录不同浓度的Tet和顺铂(DDP)对MDCK细胞KCa的Am(Current Amplitude，)、Po(Probability of Open,)、     

前列腺素E2诱导培养的大鼠脑皮质星形胶质细胞CREB及GABA_BR2磷酸化

前列腺素E2(PGE2)是一种致炎因子;星形胶质细胞中CREB和γ-氨基丁酸B受体(GABABR)的磷酸化,在神经系统炎症中起重要作用。为探讨PGE2对星形胶质细胞中CREB和GABABR2磷酸化的作用,本实验对体外培养的大鼠脑皮质星形胶质细胞以10μmol/LPGE2刺激后,用免疫组织化学和Western blot等方法研究了星形胶质细胞中CREB和GABABR2(Ser892)磷酸化水平在多个时相中的变化。结果显示:正常星形胶质细胞中存在着基础水平上的磷酸化的CREB和GABABR2(Ser892),经PGE2刺激培养,CREB和GABABR2(Ser892)磷酸化水平增高,并呈时间依赖趋势。结果提示,10μmol/L的PGE2能诱导大鼠脑皮质星形胶质细胞转录因子CREB发生磷酸化,也能诱导GABABR2(Ser892)发生磷酸化而影响细胞功能。由此,本文研究的结果说明PGE2可能在星形胶质细胞参与神经系统炎症的过程中发挥重要作用。     

果蝇中枢神经元钾离子通道电生理学研究及进展

1980年以来。膜片钳技术已可用于很多细胞系的细胞和分子水平的电生理学研究。它和基因克隆技术并驾齐驱，给生命科学带来了巨大的推动力，而神经科学领域的研究也从此豁然开朗，同时，人们找到了研究神经电生理学的最佳切入点：果蝇(Drosophila melanogaster)。果蝇中枢神经元分子机制进化上的保守性、生物学操作上无与伦比的优势、遗传背景清晰以及有众多的突变体可利用使其成为理想的动物模型：它将遗传学、分子生物学、分子神经生物学、电生理学、神经药理学等有机地结合起来。     

膜片钳技术在电生理研究中的应用

膜片钳技术是在电压钳技术的基础上发展而成的一种能精确描述细胞膜离子通道特征的研究方法。其技术特征是在微小电极与细胞膜之间形成了阻抗值高达10~9欧姆以上的高阻抗封接,极大地降低背景噪声,明显地提高通道电流的分辨率,确保微小的通道电流被准确的记录下来。膜片钳技术的发明和应用已在生物学研究中显示出非常重要的意义,为医学研究拓宽了道路。这一技术在国外已广泛开展,在国内尚处于起步阶段,还有很多工作可做,在很多相关学科的研究中有很大的应用前景。本文的目的是对被称之为“工艺”的膜片钳技术作一简介,以促进这一技术在国内的普及。     

A thin slice preparation for patch clamp recordings from neurones of the mammalian central nervous system

(1) A preparation is described which allows patch clamp recordings to be made on mammalian central nervous system (CNS) neurones in situ. (2) A vibrating tissue slicer was used to cut thin slices in which individual neurones could be identified visually. Localized cleaning of cell somata with physiological saline freed the cell membrane, allowing the formation of a high resistance seal between the membrane and the patch pipette. (3) The various configurations of the patch clamp technique were used to demonstrate recording of membrane potential, whole cell currents and single channel currents from neurones and isolated patches. (4) The patch clamp technique was used to record from neurones filled with fluorescent dyes. Staining was achieved by filling cells during recording or by previous retrograde labelling. (5) Thin slice cleaning and patch clamp techniques were shown to be applicable to the spinal cord and almost any brain region and to various species. These techniques are also applicable to animals of a wide variety of postnatal ages, from newborn to adult.     

The Effects of Vasoconstrictor Fibre Stimulation on the Consecutive Vascular Sections of the Small Intestine of the Cat during Prolonged Regional Hypotension

A plethysmographic technique was used on the cat to investigate the effects of electrical stimulation of the regional sympathetic vasoconstrictor fibres on intestinal consecutive vascular sections during prolonged hypotension at approximately 55 or 30 mm Hg produced by graded arterial occlusion. The initial peak resistance and the capacitance responses declined continuously throughout the hypotensive period, the rate of decline being higher the lower the per-fusion pressure. After 2.5 h hypotension at 30 mm Hg the nervous vasoconstrictor effects on the resistance and capacitance vessels amounted to 50 and 30 per cent of control, respectively. The reactivity of the precapillary sphincters as reflected in the capillary filtration coefficient (CFC), was largely unaltered during the hypotension at the 55 mm Hg level. At the lower perfusion pressure a marked increase of CFC was noted between and during nervous stimulations. Mean capillary hydrostatic pressure was not significantly changed by nervous activation, hut seemed to increase in the latter half of most experiments at 30 mm Hg. When releasing the arterial clamp after a 30 mm Hg hypotension the whole cardiovascular system seemed to derange progressively. Mucosal ulcerations and bleedings were regularly found in all these animals.     

Multiple effects of bisphenol A, an endocrine disrupter, on GABA(A) receptors in acutely dissociated rat CA3 pyramidal neurons

Bisphenol A (BPA), an endocrine disrupter, is contained in cans, polycarbonate bottles and some dental sealants. While the toxicological effects of BPA on the endocrine system have been extensively studied, its action on the central nervous system is poorly understood. Herein, we report the effects of BPA on GABA-induced currents (I(GABA)), using a conventional whole-cell patch clamp technique from acutely isolated rat CA3 pyramidal neurons. By itself, BPA concentration-dependently elicited the membrane current, which was significantly blocked by bicuculline, a selective GABA(A) receptor antagonist. BPA potentiated the peak I(GABA) induced by lower concentrations of GABA (<10 microM) in a concentration-dependent manner. The extent of BPA-induced potentiation of I(GABA) was significantly reduced by either diazepam or ethanol, allosteric modulators of GABA(A) receptors. BPA, however, inhibited the peak I(GABA) induced by higher concentrations of GABA (>30 microM), and accelerated the desensitization rate of I(GABA). BPA also greatly inhibited the steady state I(GABA) induced by higher concentrations of GABA (>30 microM) in a noncompetitive manner. In addition, BPA affected synaptic GABA(A) receptors as it decreased the amplitude of GABAergic miniature inhibitory postsynaptic currents in a concentration-dependent manner. Considering its complex modulatory effects on GABA(A) receptors, BPA might have potential toxicological effects on the central nervous system.     

Cordycepin decreases activity of hippocampal CA1 pyramidal neuron through membrane hyperpolarization

Cordycepin (3′-deoxyadenosine) is the main functional component of Cordycepins militaris, a renowned traditional Chinese medicine, which has been shown to possess anti-tumor, anti-inflammatory, anti-diabetic and neuro-protective effects. However, the effect of cordycepin on the central nervous system (CNS) remains unclear. In this study, the effects of cordycepin on neuronal activity were investigated on the CA1 pyramidal neurons in rat hippocampal brain slices using a whole-cell patch clamp technique. Our results revealed that cordycepin significantly decreased the frequency of both the spontaneous and evoked action potential (AP) firing. While AP spike width, the amplitude of fast after hyperpolarization (fAHP), and membrane input resistance were not altered by cordycepin, the neuronal membrane potential was hyperpolarized by cordycepin. Collectively, these results demonstrate that cordycepin reduces neuronal activity by inducing membrane hyperpolarization, indicating that cordycepin may be a potential therapeutic strategy for ischemic and other excitotoxic disorders.     

血竭及其成分龙血素B影响背根神经节细胞钠离子通道的计算机模拟研究

应用膜片钳技术，观察中药血竭及其成分龙血素B对背根神经节细胞河豚毒素敏感型钠通道电流的影响。以Hodgkin—Huxley模型拟合实验资料，进行参数估计，并对药物作用前后的细胞膜动作电位进行计算机模拟。结果表明，m^3h模型能较好地拟合河豚毒素敏感型钠通道电导；药物作用于钠通道后，半激活电压均向去极化方向偏移；药物作用后的细胞产生动作电位的阈强度提高。说明血竭及其成分龙血素B并非类似河豚毒素完全抑制河豚毒素敏感型钠通道电流。血竭可能通过其成分龙血素B影响通道的激活过程阻滞动作电位的产生，干预痛觉信息的中枢传人而产生镇痛效应。     

基因芯片技术在神经系统研究中的应用

基因芯片技术是近年来才出现的一种新的基因检测技术 ,一次基因芯片实验可以同时检测上万个基因的表达情况 ,与传统杂交技术相比具有操作简单、自动化程度高、检测效率高等优点 ,因此在基因做图、测序、病原体检测等各个方面都得到广泛的应用。本文综述了基因芯片在神经领域 ,包括神经损伤、发痛、神经系统疾病、行为学、药理机制等多个方面的应用现状 ,并对其不足作出评价。     

降钙素基因相关肽在中枢神经系统的研究进展

降钙素基因相关肽 (calcitoningene -relatedpeptide,CGRP)是一种生物活性肽 ,广泛分布于中枢神经系统和周围神经系统以及某些非神经组织。在中枢神经分布的CGRP参与机体多种调节机制 ,尤其对感觉和运动的调节 ,在胚胎发育、再生、神经内分泌等也有较强的调节作用。本文就CGRP的结构、分布、共存及在中枢各部的相关研究进行综述     

Studies of Chemoreceptor Perception in Mollusks

The formation and operation of the peripheral nervous system can be observed and studied in mollusks using as an example the primitive chemoreceptor organ, the osphradium, which is connected to the visceral arch of the CNS and analyzes the physicochemical properties of water in the mantle cavity. Nerve recordings showed that the osphradium is sensitive to excess osmotic pressure, sodium chloride, and amino acids. In addition, the osphradium responds to the quality of the water in which the animal is living. The osphradium of the pond snail retains its ancient multisensory function, uniting the perception of various chemical and physical stimuli. Patch clamp recordings at fixed potential or current were used to study membrane currents in identified ganglion and receptor cells, associated with increases in the concentrations of Na⁺ and L-aspartate in the solution bathing the osphradium. The influx current appears to be a sodium and/or calcium current, and is not blocked by tetraethylammonium, while the efflux current is a potassium current, as has been shown for the taste cells of vertebrates.     

Insulin resistance due to chronic salt restriction is corrected by alpha and beta blockade and by L-arginine

Dietary salt restriction is associated with evidence of low insulin sensitivity. The current study was undertaken to investigate whether sympathetic nervous system and l-arginine-nitric oxide pathway activities are linked to insulin resistance in rats under chronic low salt intake. Male Wistar rats were fed a low (LSD) or normal (NSD) salt diet from weaning to adulthood. A euglycemic hyperinsulinemic clamp was performed in 4 sub-groups on each diet: (1) sympathetic nervous system blockade (propranolol and prazosin), (2) vehicle, (3) L-arginine, and (4) D-arginine. Blood pressure, heart rate and metabolic measurements were done before and 45 min after drug infusion and at the end of the clamp. At baseline conditions, body weight, hematocrit, blood glucose, plasma insulin, cholesterol, and triacylglycerols were higher in LSD than in NSD rats. Systolic blood pressure was lower and heart rate was higher in rats on LSD than on NSD. Glucose uptake was lower on LSD compared to NSD. Sympathetic nervous system blockade and L-arginine did, and vehicle and D-arginine did not improve glucose uptake in LSD rats. On NSD there was no effect of any of the infused drugs. A positive correlation between plasma nitrate and nitrite at the end of clamp and glucose uptake was observed in L-arginine--but not in D-arginine-infused LSD rats. These results provide evidence that the sympathetic nervous system and the L-arginine-nitric oxide pathway are involved in the glucose uptake impairment induced by chronic dietary salt restriction.     

Neuroimmunopathology]

The paper deals with a part of neuroimmunopathology which is concerned with the role of the pathologically altered nervous system in the pathology of the immune system and vice versa and considers disturbances in the interconnection of nervous and immune systems. Antibodies against neuromediators and nervous tissue can produce both pathogenetic and sanogenic effects depending on the neurotransmitter function or the nervous structure which they are specifically directed towards. The effects of systematically administered antibodies against nervous tissue and neuromediators demonstrate that antibodies can penetrate into the central nervous system (CNS). The adoptive transfer of the signs of a pathological condition by immunocytes from CNS abnormalities illustrates the role of the immune system in nervous diseases.