线粒体及内质网对铅引起的[Ca2+]i升高的作用

目的 研究线粒体、内质网Ca^2 -ATP酶以及Na^ 和K^ -ATP酶活力的改变对铅引起的[Ca^2 ]i升高的调节作用，探讨铅引起的[Ca^2 ]i增高对学习记忆功能的影响。方法 Wistar大鼠神经肉瘤C6细胞培养于含醋酸铅的培养液中，于不同时间终止染铅，检测[ca2’]；及线粒体、内质网Ca^2 -ATP酶、Na^ 和K^ -ATP酶活力。结果 (1)0．2μmol／L染铅组：[Ca^2 ]i轻度升高，线粒体Ca^2 -ATP酶、Na^ 和K^ -ATP酶活力升高，内质网酶活力略增高；(2)1．0μmol／L染铅组：[Ca^2 ]；于染铅后0．5h升至最高，以后逐渐降低，波动于iL60～190nmol／L之间；线粒体、内质网Ca^2 -ATP酶、Na^ 和K^ -ATP酶于染铅后0．5h升至最高(分别为未染铅前酶活力的29．1、39．2、10．8和19．8倍)，2d后降至接近正常水平。结论 (1)铅可使Wistar大鼠神经肉瘤C6细胞Ca^2 浓度及线粒体、内质网Ca^2 -ATP酶、Na^ 和K^ -ATP酶活力增高；(2)当[Ca^2 ]i增高不显著时以线粒体Ca^2 -ATP酶、Na^ 和K^ -ATP酶活力增高为主；当[Ca^2 ]i急剧升高时，线粒体、内质网Ca^2 -ATP酶、Na^ 和K^ -ATP酶活力均明显增高，尤其是线粒体Ca^2 -ATP酶、Na^ 和K^ -ATP酶活力增高更为显著。     

雷米普利对舒张眭心力衰竭大鼠心房肌L型钙通道的影响．

目的观察雷米普利对舒张性心力衰竭（DHF）大鼠模型心房肌细胞L型钙通道的影响。方法腹主动脉缩窄术建立DHF大鼠模型,随机分为DHF组及雷米普利大、中、小剂量组,另设对照组。全细胞膜片钳检测心房肌细胞L型钙通道电流（ICa—L）;RT—PCR检测L型钙通道上Cav1.2mRNA的表达;Western blot检测钙调控相关蛋白LTCC的表达。结果与对照组比较,DHF组大鼠心房肌细胞ICa—L电流密度峰值、Cav1.2mRNA表达及钙调蛋白LTCC的表达明显降低（P〈0．05）;与DHF组比较,雷米普利组心房肌细胞ICa—L电流密度峰值明显增加、Cav1-2mRNA及钙调控蛋白LTCC的表达增加（P〈0．05）,且剂量越大增加越明显。结论雷米普利能上调舒张性心力衰竭大鼠心房肌ICa—L电流密度峰值,增加Cav1.2mRNA及钙调控蛋白LTCC的表达,对DHF大鼠有治疗作用．其机制与调控心房肌细胞L型钙通道的功能有关。     

TRPV1对LPS致热大鼠体温及下丘脑中Ca2＋浓度和cAMP含量的影响

目的探讨TRPV1在脂多糖（LPS）致大鼠发热过程中的作用和机制。方法48只6SD大鼠随机分为4组,正常对照组（N）、capsazepine组（CPZ）、LPS组（LPS）和capsaz—epine＋LPS组（CPZ＋LPS）。连续观察体温变化;在发热高峰期通过颈椎脱臼迅速处死动物,以Fura-2／AM为荧光指示剂,测定下丘脑细胞内[Ca2＋]i;应用放射免疫法检测下丘脑中cAMP含量的变化。结果①各组体温变化最大值（△Tmax）由高至低顺序为：CPZ＋LPS组〉LPS组〉CPZ组〉N组;其中,CPZ＋LPS组与LPS组比较,AT（300～480min期间）及体温反应指数TRI。均增高（P〈0．01）;②在发热高峰期,CPZ＋LPS组[Ca2＋]i明显低于其它3组（P〈0．01）;③CPZ＋LPS组cAMP含量与其它组比较增多（P〈0．01）。结论capsazepine可能通过阻断下丘脑TRPV1通道,改变细胞内钙离子浓度,进而影响LPS性发热过程。     

心肌肽素对豚鼠心室肌细胞L型钙通道的影响

目的研究心肌肽素对豚鼠心室肌细胞L型钙通道的影响,探讨心肌肽素在离子通道水平的药理作用机制。方法用急性酶解分离法获得豚鼠心室肌细胞,标准的全细胞膜片钳技术记录L型钙电流(ICa-L)。结果心肌肽素1、5、10、50、100、500 mg.L-1使豚鼠心室肌细胞ICa-L分别增加(5±4)%、(21±5)%、(30±5)%、(55±8)%、(76±11)%、(80±9)%,半最大效应浓度(EC50)为(18±6)mg.L-1。心肌肽素50 mg.L-1使ICa-L激活时间(TTP)从(6.7±0.9)m s缩短为(5.9±0.7)m s(P<0.01);使ICa-L电流密度-电压曲线下移,但激活电压、峰电压和I-V曲线的形状不变;激活曲线向负电压方向变化,半数激活电压从(-4.3±0.4)mV减少至(-8.6±0.4)mV(P<0.05);不影响稳态失活曲线和稳态失活后恢复曲线。结论心肌肽素浓度依赖性增强豚鼠心室肌细胞ICa-L。     

慢性染铅对大鼠海马区神经细胞Ca2+浓度及Ca2+-ATP酶活性的影响

目的：观察慢性染铅对大鼠海马区神经细胞Ｃａ２＋浓度及Ｃａ２＋－ＡＴＰ酶活性的影响。方法：用０．１５％醋酸铅饲养大鼠建立慢性染铅动物模型,参照Ｄｉｌｄｙ法和徐友涵法测定海马神经细胞Ｃａ２＋浓度及Ｃａ２＋－ＡＴＰ酶活性。结果发现：细胞内Ｃａ２＋浓度,染铅组（２０３．８３±３０．５０）ｎｍｏｌ／Ｌ,对照组（９７．６２±１９．８３）ｎｍｏｌ／Ｌ,ｔ＝８．３１Ｐ＜０．００５;Ｃａ２＋－ＡＴＰ酶活性,染铅组（３２６．４２±４０．０６）ｎｍｏｌ（Ｐｉ）·ｍｇ－１·ｍｉｎ－１,对照组（２５３．０７±２５．４０）ｎｍｏｌ（Ｐｉ）·ｍｇ－１·ｍｉｎ－１,ｔ＝３．５４,Ｐ＜０．０１。结论：慢性染铅可使大鼠海马区神经细胞内Ｃａ２＋浓度升高,Ｃａ２＋－ＡＴＰ酶活性增强     

参麦注射液与氨茶碱对膈肌细胞Ca2+浓度的影响

目的 :探讨参麦注射液与氨茶碱对膈肌细胞内游离Ca2 浓度的影响。方法 :体外培养大鼠膈肌细胞 ,荧光光度法测定参麦注射液与氨茶碱处理前后细胞内Ca2 浓度的变化。结果 :氨茶碱可使膈肌细胞内的Ca2 浓度明显升高(P<0.01) ,维拉帕米或预先去除培养液中Ca2 可消除该作用。参麦注射液对膈肌细胞内Ca2 浓度无明显影响(P>0.05)。缺氧24h即可致膈肌细胞内Ca2 浓度明显升高(P<0.01) ,参麦注射液对缺氧24h所致的膈肌细胞内Ca2 浓度升高有抑制作用。结论 :细胞外Ca2 是氨茶碱导致细胞内Ca2 升高的关键因素 ,氨茶碱可通过促进细胞外Ca2 内流导致细胞内Ca2 升高。参麦注射液可抑制缺氧所致的膈肌细胞内Ca2 超载 ,对细胞有一定的保护作用。以上作用分别参与了二者抗膈肌疲劳的机制     

软骨藻酸对H4细胞氨基酸释放和Ca2+浓度的影响

目的　研究软骨藻酸 (domoicacid)对H4细胞的兴奋性、抑制性氨基酸释放和胞内游离Ca2 ( [Ca2 ]i)浓度的影响。方法　应用高效液相色谱 (HPLC)和荧光分光光度计检测 0、0 0 64、0 64和 6 4μmol/L软骨藻酸作用于细胞 2h后的兴奋性、抑制性氨基酸释放和 [Ca2 ]i浓度。结果　天冬氨酸和谷氨酸 :中、高剂量组均高于对照组 ,差异有显著性(P <0 0 5 ) ;甘氨酸 :仅高剂量组高于对照组 ,差异有显著性 (P <0 0 5 ) ;γ 氨基丁酸 :低、中和高剂量组均低于对照组 ,差异有显著性 (P <0 0 5 ) ;兴奋性氨基酸 /抑制性氨基酸 :低、中和高剂量组均高于对照组 ,差异有显著性 (P <0 0 5 )。胞内[Ca2 ]i :低、中和高剂量组分别为 ( 2 0 8 65± 11 0 1)、( 3 42 3 1± 15 0 8)和 ( 5 81 3 6± 17 2 4)nmol/L ,高于对照组 [( 14 3 2 5±11 97)nmo1/L] ,差异有显著性 (P <0 0 1)。兴奋性氨基酸与 [Ca2 ]i浓度有显著的正相关性 (r =0 93 2 0P <0 0 1)。结论　软骨藻酸能引起H4细胞兴奋性和抑制性氨基酸释放和胞内 [Ca2 ]i变化 ,这种变化可能是软骨藻酸兴奋性神经毒性的重要机制     

苯并[a]芘和铅对小鼠的联合神经毒性及脑组织的影响

目的研究苯并[a]芘(benzo[a]pyrene BaP)、铅单独与联合作用对小鼠的神经毒性及小鼠脑组织热应激蛋白(HSPs)HSP 70、HSP 90β表达的影响。方法将80只昆明种小鼠随机分为10组，每组8只，既：空白对照组、溶剂对照组、低浓度铅染毒组、高浓度铅染毒组、低剂量BaP染毒组、高剂量BaP染毒组、低浓度铅 低剂量BaP染毒组、低浓度铅 高剂量BaP染毒组、高浓度铅 低剂量BaP联合染毒组和高浓度铅 高剂量BaP联合染毒组。低、高剂量BaP染毒分别为0．5和5mg／kg BaP的植物油溶剂每周4次腹腔注射，溶剂对照组用植物油作平行处理。低、高剂量的铅染毒分别为5．4和54mg／L醋酸铅饮水染毒。实验中观察动物一般情况及神经系统损伤表现，实验8周后取各组小鼠脑组织，称重并计算脑组织脏器系数。制作脑组织混合匀浆，western blot法检测HSP70、HSP90β水平。结果BaP与铅联合染毒可使小鼠脑组织脏器系数降低；HSP900β相对表达值与脑组织脏器系数量负相关。结论BaP与铅联合作用可明显损伤脑组织；HSP90β对上述损害起标志作用。     

α-芋螺毒素[A10L]PnIA荧光探针的设计合成及活性研究

α7烟碱型乙酰胆碱受体(nAChR)广泛分布于中枢和外周神经系统,与多种神经系统疾病、炎症反应密切相关.α-芋螺毒素[A 10L]PnIA作为靶向α7 nAChR的拮抗剂,对研究α7 nAChR相关生理、病理过程具有重要作用.利用荧光素5-羧基四甲基罗丹明标记[A 10L]PnIA,体外两步法氧化折叠获得活性肽([A1...     

黎芦碱对分离的大鼠神经细胞内游离钙的影响

用Ｆｕｒａ－２双波长荧光法测得分离的大鼠神经细胞静息胞内游离钙浓度（［Ｃａ２＋］ｉ）为１１９．４±９．１ｎｍｏｌ·Ｌ－１（ｎ＝８）．藜芦碱（１０－４ｍｏｌ·Ｌ－１）可显著促进Ｃａ２＋内流而使［Ｃａ２＋］ｉ升高（Ｐ＜０．０１，ｎ＝８）；尼莫地平对静息［Ｃａ２＋］ｉ无影响．但能浓度依赖性地对抗藜芦碱所致［Ｃａ２＋］ｉ的升高。提示藜芦碱诱发的［Ｃａ２＋］ｉ升高由存在于神经细胞膜上的Ｌ型电压依赖性钙通道介导；尼莫地平可用以间接地保护神经细胞免受藜芦碱的兴奋毒性。     

Effects of flunarizine on induced calcium transients as measured in fura-2-loaded neurons of the rat dorsal root ganglion

Summary The effect of the calcium entry blocker flunarizine on a high-potassium induced increase of intracellular free calcium was studied. The experiments were done with neurons isolated from rat dorsal root ganglia and loaded with the calcium-sensitive dye fura-2. The increase of calcium induced by 60 mmol/1 potassium was abolished after removal of extracellular calcium, was reversibly reduced by 50 mol/l cadmium (76% inhibition), 50 mol/1 nickel (25% inhibition) and 10 mol/1 nifedipine (18°10 inhibition), and reversibly increased after removal of extracellular sodium (26% increase). The potassium induced increase of intracellular calcium is, therefore, mediated by transmembrane calcium influx, probably to a large extent through cadmium-sensitive calcium channels. Flunarizine (5 min incubation followed 1 min wash-out) reduced the amplitude of the high-potassium induced calcium increase in a dose-dependent manner (K _d = 370 ± 100 nmol/l; mean ± SEM; n = 8), causing complete inhibition at a concentration of 10 mol/1 in the majority of cells. Flunarizine ( 1 mol/1) caused a reversible increase of the resting level of intracellular calcium in some cells, an effect which disappeared in the absence of extracellular calcium. The drug (1 mol/1 had no influence on the time course of recovery of intracellular calcium subsequent to a rise induced by high-potassium or by the calcium ionophore A23187. It is concluded that flunarizine acts as an inhibitor of depolarization-mediated calcium influx. At a concentration of 1 mol/1, the drug presumably has no effect on cellular calcium extrusion and/or sequestration mechanisms. Correspondence to L. Leybaert at the above address     

Intracellular free calcium concentration in rat anterior pituitary cells as indicated by fura-2: effect of arginine-vasopressin

Summary Arginine-vasopressin (AVP) stimulates adrenocorticotropin and -endorphin release from corticotrophs of the anterior pituitary gland through mechanisms which are not initiated by an elevation of the cellular levels of adenosine-3,5-cyclic-monophosphate. In the present study the effect of AVP on the cytoplasmic concentrations of free calcium ions in rat anterior pituitary cells was examined. Cytosolic free Ca²⁺ concentrations were monitored directly using the new, intracellularly trapped fluorescent indicator fura-2. In cells incubated in medium containing 1.3 mmol/l Ca²⁺, AVP (100 nmol/l) caused an immediate elevation of the cytoplasmic Ca²⁺ concentration by about 50 nmol/l (P < 0.001). The intracellular Ca²⁺ levels remained elevated during the observation period of 2–3 min. This effect of AVP was blocked by a specific vasopressin antagonist. By contrast, the glucocorticoid dexamethasone did not affect the AVP-induced elevation of cytosolic Ca²⁺ concentration. When the cells were incubated in Ca²⁺-free medium (Ca²⁺ omitted, EGTA 2 mmol/l), the AVP-induced as well as the K⁺ depolarization-induced increase in free cytoplasmic Ca²⁺ were abolished, whereas the ionophore ionomycin evoked a rapid transient elevation of free Ca²⁺. The increase in cytoplasmic Ca²⁺ concentration induced by AVP was preserved in medium containing the calcium channel blockers Mg²⁺ (Mg²⁺ 31.2 mmol/l; Ca²⁺ 1.3 mmol/l) or nifedipine (1 mol/l). The potassium-evoked calcium signal was blocked by Mg²⁺ (31.2 mmol/l). We conclude that vasopressin induces a rapid rise in the cytoplasmic concentration of free calcium ions in corticotrophs. Vasopressin may mobilize calcium through mechanisms that neither are glucocorticoid-sensitive nor involve the influx of extracellular celcium through voltage-dependent calcium channels. The rise in Ca²⁺ concentration may be an early intracellular signal that links the cell-surface receptors for vasopressin to secretion of ACTH and -endorphin. Send offprint requests to W. Knepel     

汉防己甲素抑制三种神经递质引起的新生大鼠脑细胞内游离钙的升高

应用Ｐｕｒａ－２技术测定游离新生大鼠脑［Ｃａ２＋］ｉ浓度的技术、研究了Ｔｅｔ对静息脑［Ｃａ２＋］ｉ和３种递质引起的脑［Ｃａ２］ｉ变化的影响。Ｔｅｔ（１，１０和２０μｍｏｌ·Ｌ－１）对静息脑［Ｃａ２＋］ｉ无明显影响。Ｔｅｔ（１０μｍｏｌ·Ｌ－１）可降低Ｌ－Ｇｌｎ（０．１、１．０和１０μｍｏｌ·Ｌ－１）引起的脑（Ｃａ２＋）ｉ的升高。在Ｈａｎｋ＇ｓ液Ｃａ２＋为１．３ｍｍｏｌ·Ｌ－１时，Ｔｅｔ１０μｍｏｌ·Ｌ－１可降低Ｈｉｓ（５０和１００μｍｏｌ·Ｌ－１）和５－ＨＴ（０．１、１．０、１０和１００μｍｏｌ·Ｌ－１）引起的脑［Ｃａ２＋］ｉ的升高。但不能降低Ｈａｎｋ＇ｓ液无Ｃａ２＋时Ｈｉｓ和５－ＨＴ引起的脑［Ｃａ２＋］ｉ的升高。研究表明Ｔｅｔ可阻滞Ｌ－Ｇｉｎ、Ｈｉｓ和５－ＨＴ受体调控的钙通道。但对Ｈｉｓ和５－ＨＴ引起的细胞内贮存钙的释放并无明显影响。Ｔｅｔ的这种降低脑［Ｃａ２＋］ｉ的作用可能是其治疗脑缺血性疾病的机理之一。Ｐ＜０．０１在Ｔｅｔ１０μｍｏｌ·Ｌ－１作用下，相同浓度的细胞外液钙和Ｈｉｓ（０、５０和１００μｍｏｌ·Ｌ－１），脑［Ｃａ２＋］ｉ分别是２２１±５、２４５±５和３０２±６ｎｍｏｌ·Ｌ－１。增加了１１．８?     

Cannabidiol-induced intracellular Ca2+ elevations in hippocampal cells

The phytocannabinoid cannabidiol (CBD) is at the forefront of therapeutic cannabinoid research due to its non-psychotropic properties. Research supports its use in a variety of disorders, yet the cellular mechanisms of its action remain unclear. In this study, the effect of CBD upon Ca2+ homeostasis in hippocampal cells was characterised. CBD (1 microM) elevated intracellular Ca2+ ([Ca2+]i) by approximately +45% of basal Ca2+ levels in both glia (77% responders) and neurones (51% responders). Responses to CBD were reduced in high excitability HEPES buffered solution (HBS), but not affected in low excitability/low Ca2+ HBS. CBD responses were also significantly reduced (by 50%) by the universal Ca2+ channel blocker cadmium (50 microM) and the L-type specific Ca2+ channel blocker nifedipine (20 microM). Interestingly, intracellular store depletion with thapsigargin (2 microM) had the most dramatic effect on CBD responses, leading on average to a full block of the response. Elevated CBD-induced [Ca2+]i responses (>+100%) were observed in the presence of the CB1 receptor antagonist, AM281 (1 microM), and the vanilloid receptor antagonist, capsazepine (CPZ, 1 microM). Overall, our data suggest that CBD modulates hippocampal [Ca2+]i homeostasis via intracellular Ca2+ stores and L-type VGCC-mediated Ca2+ entry, with tonic cannabinoid and vanilloid receptor signalling being negatively coupled to this pathway.     

缺氧缺糖条件下大鼠脑皮质神经元内游离钙浓度的变化及神经生长因子的作用

以Fura-2/AM为细胞内钙离子的荧光指示剂,用双波长荧光分光光度计测定了缺氧缺糖时体外培养的大鼠胎鼠神经细胞内游离钙([Ca²⁺]i)的变化,并观察了神经生长因子(NGF)的影响。结果表明,脑皮质细胞缺氧缺糖培养16～24h时,细胞大量死亡。NGF剂量依赖地减少神经元缺氧缺糖培养24h时乳酸脱氢酶(LDH)的释放,提高细胞生存力。细胞缺氧缺糖早期引起[Ca²⁺]i减少,而后期引起[Ca²⁺]i显著升高,导致细胞损害。NGF50μg·L^-1在缺氧缺糖早期提高[Ca²⁺]i到正常水平,降低后期[Ca²⁺]i的升高。提示,NGF通过稳定[Ca²⁺]i或降低后期的胞内钙升高保护了脑皮质神经元免受缺氧缺糖的损害。     

Effects of Apigenin on Glutamate-induced [Ca2+]i Increases in Cultured Rat Hippocampal Neurons

Flavonoids have been shown to affect calcium signaling in neurons. However, there are no reports on the effect of apigenin on glutamate-induced calcium signaling in neurons. We investigated whether apigenin affects glutamate-induced increase of free intracellular Ca²⁺ concentration ([Ca²⁺]_i) in cultured rat hippocampal neurons, using fura-2-based digital calcium imaging and microfluorimetry. The hippocampal neurons were used between 10 and 13 days in culture from embryonic day 18 rats. Pretreatment of the cells with apigenin (1 µM to 100 µM) for 5 min inhibited glutamate (100 µM, 1 min) induced [Ca²⁺]_i increase, concentration-dependently. Pretreatment with apigenin (30 µM) for 5 min significantly decreased the [Ca²⁺]_i responses induced by two ionotropic glutamate receptor agonists, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA, 10 µM, 1 min) and N-methyl-D-aspartate (NMDA, 100 µM, 1 min), and significantly inhibited the AMPA-induced peak currents. Treatment with apigenin also significantly inhibited the [Ca²⁺]_i response induced by 50 mM KCl solution, decreased the [Ca²⁺]_i responses induced by the metabotropic glutamate receptor agonist, (S)-3,5-dihydroxyphenylglycine (DHPG, 100 µM, 90 s), and inhibited the caffeine (10 mM, 2 min)-induced [Ca²⁺]_i responses. Furthermore, treatment with apigenin (30 µM) significantly inhibited the amplitude and frequency of 0.1 mM [Mg²⁺]_o-induced [Ca²⁺]_i spikes. These data together suggest that apigenin inhibits glutamate-induced calcium signaling in cultured rat hippocampal neurons.     

水杨酸镁对胎鼠脑细胞内钙的影响

目的　观察水杨酸镁对脑细胞内钙的影响 ,探讨其中枢神经系统的钙拮抗作用。方法　应用新一代钙离子指示剂Fura 2 /AM技术 ,用双波长荧光分光光度计测定细胞内钙浓度。结果　在不同外钙条件下 (外钙 0 ,0 0 1,0 1,1 0 ,1 3mmol·L-1)细胞内静息钙浓度分别 41± 5 ,5 9± 6 ,84 7± 2 5 ,10 4± 7,(12 6± 5 )nmol·L-1(各组n =8)。水杨酸镁0 2mmol·L-1对静息细胞内钙无显著影响 (P >0 0 5 )。但水杨酸镁 (0 0 5～ 0 4mmol·L-1)可以剂量依赖性抑制高钾及L 谷氨酸诱发的细胞内钙增高。其IC50 分别为 0 32 3mmol·L-1(95 %CI为 0 12 2～ 0 85 4mmol·L-1)和 0 12 4mmol·L-1(95 %CI为 0 0 73～ 0 2 10mmol·L-1)。结论　水杨酸镁通过抑制电压依从性及受体操纵型的钙通道 ,对中枢神经系统具有较强的钙拮抗作用。