5-羟色胺对培养胃底平滑肌细胞内游离钙动员的影响

目的　研究 5 - HT诱导胃底平滑肌细胞内钙动员的机制 .方法　采用 Ca2 +指示剂 Fluo- 3/ AM作为细胞内钙离子的荧光探针负载培养的胃底平滑肌细胞 ,共聚焦技术检测细胞内钙荧光强度的变化 .结果　基础状态下 SFSMC[Ca2 + ]i 荧光强度 (FI)为 2 6 4± 15 ,5 - HT 10μmol· L- 1 使荧光强度的变化 ΔFI为 16 .5± 2 .6 ;细胞外无钙时 ,5 - HT升高[Ca2 + ]作用被减弱 ,但除去细胞外钙 ,并使用内罗啶 (ryan-odine)孵育后 ,5 - HT 不再引起荧光强度的变化 ;10μmol· L- 1 米安舍林 (mianserin)可部分拮抗 5 - HT升高[Ca2 + ]i 的作用 ,赛更定 (cyprohetadine)不能抑制 5 - HT升高的胞内钙 ;Mn92 0 2和拉西地平 (lacidipine)均能完全抑制 5 -HT升高 [Ca2 + ]i 的作用 .结论　 5 - HT可通过促进外钙内流及钙池 (SR)释放使 [Ca2 + ]i 升高 ;在胃底平滑肌 5 - HT升高胞内钙部分通过 5 - HT2 受体 ,而不是通过 5 - HT1 C受体 ;5 -羟色胺通过 L型钙通道促外钙内流 ;二氢吡啶类钙拮抗剂能通过阻滞 L 型钙通道 ,而完全抑制 5 - HT促胞内钙升高的作用     

1-(2, 6-二甲基苯氧基)-2-(3, 4-二甲氧基苯乙氨基) 丙烷盐酸盐对培养的乳鼠心肌细胞[Ca2+]i的影响

采用 Fura- 2 / AM显微荧光测钙技术 ,检测培养新生大鼠单个心肌细胞内游离钙的浓度 ,并观察 1- (2 ,6 -二甲基苯氧基 ) - 2 - (3,4-二甲氧基苯乙氨基 )丙烷盐酸盐 (DDPH)对不同刺激〔去氧肾上腺素 ,高 K ,血管紧张素 (Ang II)〕所致心肌细胞钙超载的影响。结果表明 :1在含钙、无钙标准台氏液 ,DDPH 10 - 4 m ol· L- 1 对去氧肾上腺素(Phe) 10 - 4 mol· L- 1 所致钙增高有显著抑制作用。 2 DDPH 10 - 4 m ol· L- 1 对高 K 5 0 m mol· L- 1 引起的 [Ca2 ]i增高有一定抑制作用 ,对 Ang 10 - 4 mol· L- 1 引起的 [Ca2 ]i增高有部分拮抗作用。提示 :DDPH可拮抗 α1 受体调控的 Ca2 通道 ,对钙库钙释放也有抑制作用 ,对电压依赖性钙通道有一定调控作用     

滨蒿内酯对ryanodine介导哮喘豚鼠气道平滑肌细胞内钙释放的抑制作用

目的该实验就滨蒿内酯(Scoparone,Sco)降低气道平滑肌细胞(airway smooth muscle Cells,ASMC)细胞内钙浓度(cytoplasmic Ca2+concentration,[Ca2+]i)的途径及平喘作用的机理进行初步的探讨。方法建立卵蛋白诱导的哮喘豚鼠模型,通过离体豚鼠气管环的舒缩实验和测定培养的ASMCs[Ca2+]i浓度的方法,分析Sco对哮喘豚鼠ryanodine受体介导的内钙释放的影响。结果显示在细胞外含钙或无钙时,预先给予Scoparone可抑制5μmol/L ryanodine引起的正常、哮喘组豚鼠离体气管环收缩反应;Scoparone可明显降低对照组及哮喘组豚鼠原代培养ASMCs[Ca2+]i水平且哮喘组更为明显(P<0.01);Scoparone明显降低原代培养的ASMCs[Ca2+]i对5μmol/L ryanodine的反应性(P<0.01)。结论 Sco明显降低正常和哮喘豚鼠原代培养的ASMCs[Ca2+]i,对后者的作用明显大于前者;Sco对ASMCs的[Ca2+]i降低作用主要是通过抑制细胞内钙释放途径实现的,明显抑制哮喘豚鼠ASMCs ryanodine受体介导的内钙释放。     

RyR2磷酸化在心力衰竭中的作用

 心力衰竭在细胞水平主要表现为心肌以兴奋 收缩耦联(excitement contraction coupling,ECC)为基础的收缩功能障碍,而Ca2+信号转导在此过程中起着非常重要的作用。肌浆网(sarcoplasmic reticulum,SR)兰尼碱受体(ryanodine receptor type 2,RyR2)是心肌最重要的钙释放通道,RyR2磷酸化是肌浆网钙释放的基础,而RyR2磷酸化主要受蛋白激酶A (protein kinase A ,PKA)和钙离子/钙调蛋白依赖性蛋白激酶Ⅱ (calcium/calmodulin dependent protein kinase Ⅱ,CaMKⅡ)的调控。目前对RyR2磷酸化的研究已经非常广泛,但对其涉及心力衰竭的具体发病机制仍有争议,本综述主要针此问题进行阐述。     

新生大鼠心肌细胞内Ca2+的空间分布及调控的离体研究

采用激光扫描共聚焦显微镜、荧光分光光度计和荧光显微镜,观察培养的大鼠心肌细胞和离体细胞核的Ca2+信号变化.结果:培养的心肌细胞内Ca2+荧光分布不均匀,即核的荧光强度显著高于胞浆;β-受体激动剂异丙肾上腺素(10-6mol/L)使核钙浓度[(Ca2+)n]增加程度显著大于胞浆钙浓度[(Ca2+)c],β-受体阻滞剂心得安(10-3mol/L)浓度显著降低细胞核/胞浆游离钙梯度;P物质(10-6mol/L)作用下,[(Ca2+)n]增加2.17倍,而[(Ca2+)c]仅增加91.45%(P<0.05),[(Ca2+)n]/[(Ca2+)c]大幅度上升.心肌细胞经钙泵抑制剂thapsigargin和EGTA刺激后,可见核膜腔存在钙库.正常心肌细胞存在小幅度的钙震荡,分别加入去甲肾上腺素(10-5mol/L)、AngⅡ(10-6mol/L)和ATP(3×10-3mol/L),均使心肌细胞胞浆Ca2+和核Ca2+震荡幅度明显升高(P<0.01),NO-供体硝普钠(10-5mol/L)和KCI(20mmol/L)使钙的周期性震荡消失.IP3和Ryanodine分别使核Ca2+短暂升高1.68倍和1.93倍(P<0.001),而Thapsigargin预处理心肌细胞核,均能显著的阻断IP3和Ryanodine的致核Ca2+升高作用(P<0.05),荧光染色观察可见IP3受体染色主要位于核内膜,而钙泵和ryanodine受体染色主要位于核外膜.结论:心肌细胞核是细胞内的钙库之一,心肌细胞核也存在Ca2+震荡,并受多种因素影响.心肌细胞核膜上存在Ca2+-ATPase、RyR和IP3受体等核Ca2+摄取和释放系统.核Ca2+释放的前提条件是首先存在核Ca2+摄取.     

新生大鼠心肌细胞内Ca2+的空间分布及调控的离体研究

游离钙是细胞内最为关键的第二信使,参与细胞内许多重要生命过程的调节.因此胞浆和核钙稳态的精密调节,将对细胞功能的维持具有至关重要的意义.真核细胞核是细胞遗传信息和生命活动的控制中心,由于心肌细胞内的游离钙随心脏的收缩周期呈大幅度的周期性变化,细胞核上是否存在核Ca2+调节系统,从而保证在心肌胞浆Ca2+大幅度周期变化时核功能的精密调节,已成为国内外学者争论的热点.本研究在培养的新生大鼠心肌细胞上,以Fluo-4/AM荧光指示剂负载心肌细胞,应用激光共聚焦扫描显微镜,观察多种工具药对胞浆和核Ca2+的空间分布和钙信号的变化形式的影响,以初步揭示心肌细胞核上是否存在相对独立的钙调节系统.结果显示,心肌细胞核的荧光强度明显高于细胞浆,并存在小幅度的钙震荡,AngⅡ使胞浆及其核内的钙震荡幅度均增大,其作用可被NO所完全抑制.Ca2+-ATPase抑制剂thapsigargin(10-6mol/L)、钙释放通道ryanodine受体2激动剂咖啡因(5mmol/L)和大剂量L-型Ca2+通道阻滞剂verapamil(500μmol/L),不仅使心肌细胞胞浆内出现钙闪烁现象,核膜上也出现钙闪烁团.EGTA首先螯合心肌细胞胞内的游离Ca2+,继之螯合胞浆钙库Ca2+,最后仅显示心肌细胞核膜腔Ca2+库影.L-型Ca2+通道阻滞剂verapamil引起心肌细胞自发的钙波传递消失,核和胞浆内荧光强度一过性升高后下降,且核钙升高的幅度明显高于胞浆.由此说明心肌细胞胞浆和核内均存在钙震荡、钙闪烁、钙波以及瞬时性钙增高等多种钙信号形式.核Ca2+与胞浆Ca2+之间存在一定的屏障,核与胞浆Ca2+变化不完全同步.心肌细胞受到外来因素刺激后,也启动核内钙调节系统形成核Ca2+震荡等钙信号.心肌细胞核也可能作为胞内钙库起作用,并具有相对独立的钙转运系统,胞浆和核Ca2+库对Ca2+的摄取和释放在细胞功能的调节中可能起重要作用.不同亚细胞定位的Ca2+信号可能通过频率和幅度的差异来编码外来信息,进而影响细胞的各种功能.     

家兔未成熟心肌缺血再灌注肌浆网摄钙功能的初步研究

目的 :从亚细胞水平研究未成熟心肌缺血 -再灌注损伤中肌浆网 (SarcoplasmicReticulum ,SR)摄钙功能。方法 :36只家兔随机分为 4组 ,进行离体心灌注。组Ⅰ :幼兔 ,单纯灌注 30min ;组Ⅱ :幼兔 ,停搏 6 0min ,再灌注 30min。组Ⅲ、组Ⅳ为成兔 ,处理分别同组Ⅰ、组Ⅱ ,进行对照。测定各组心功能、冠状动脉流出液血气 ,单细胞内游离钙离子浓度 ([Ca2 + ]i) ,肌浆网Ca2 + -ATPase活性 ,肌浆网45Ca2 + 摄取。结果 :缺血 -再灌注后 ,成熟与未成熟心肌均发生钙超载 (P >0 .0 5 )。未成熟心肌肌浆网Ca2 + ATPase活性 ,肌浆网45Ca2 + 摄取恢复率 ,明显高于成熟心肌 (P <0 .0 5 )。结论 :未成熟心肌缺血 -再灌注损伤钙超载机制不同于成熟心肌 ,肌浆网钙摄取功能 ,在钙超载损伤中不起主要作用。     

第4代钙通道阻滞剂西尼地平的临床应用研究进展

西尼地平是第4代二氢吡啶类钙通道阻滞剂,它不仅能与血管平滑肌细胞上的L型钙通道的二氢吡啶位点结合,抑制Ca2+通过L型钙通道的跨膜内流,从而松弛和舒张血管平滑肌,发挥降压作用;而且还可以抑制Ca2+通过交感神经细胞膜上的N型钙通道的跨膜内流,减少交感神经末梢去甲肾上腺素的释放和降低交感神经的活性.L型钙通道主要分布在心脏和血管,调节心肌收缩力、窦房结功能和血管张力.N型钙通道主要存在于交感神经和中枢神经系统的末梢,调节神经递质释放,N型钙通道在神经元之外的心脏、心肌和平滑肌细胞等多组织细胞中均有分布[1].     

平滑肌肌浆网Ca~(2+)释放与STOCs相关性的研究进展

平滑肌细胞肌浆网(SR)上存在两种不同类型的钙释放通道:三磷酸肌醇敏感的钙释放通道(IP3R)和ryanodine敏感的钙释放通道(RyRs)。肌浆网产生的局部瞬时钙释放如钙火花或Ca2+puffs激活邻近胞膜上的钙激活钾通道产生自发性瞬时外向电流(STOCs)。近来研究表明IP3Rs和RyRs都参与肌浆网内钙的调节和平滑肌的舒张。这两种释放通道是否存在协同作用,以及如何影响STOCs,进而调控平滑肌的舒缩活动,不同组织存在很大差异。本文就此方面的研究进展进行综述。     

环维黄杨星D对大鼠在体回肠的作用及其机制

目的:探讨中药单体环维黄杨星D(CVB-D)对大鼠在体回肠的作用及其机制.方法:经十二指肠插管给予不同浓度的CVB-D,观察CVB-D对回肠收缩的影响,并分离培养大鼠回肠平滑肌细胞,应用钙敏感的荧光指示剂Fura-2,于荧光分光光度计上测定平滑肌细胞内游离钙离子浓度([Ca2 ]i).结果:给药组在给予CVB-D 110 min以后大鼠回肠的收缩幅度增强,而预先给予钙通道阻滞药硝苯地平可拮抗其对回肠的收缩作用.当回肠平滑肌细胞悬液细胞外钙([Ca2 ]o)为1.5 mmol/L时,CVB-D可诱发静息期[Ca2 ]i升高,而预先给予维拉帕米可以抑制[Ca2 ]i的升高,抑制率为17.9%;当[Ca2 ]o为零时,CVB-D仍可使[Ca2 ]i升高,而普鲁卡因对[Ca2 ]i升高的抑制率达29.2%.结论:大鼠回肠平滑肌受CVB-D刺激后,回肠的收缩幅度明显增加,作用机制可能与增加肠平滑肌细胞[Ca2 ]i有关,而[Ca2 ]i增加主要来源于细胞外Ca2 经电压依赖性钙离子通道内流及肌浆网雷诺定(ryanodine)敏感的贮存Ca2 释放.     

Lead Can Inhibit NMDA^—,K^＋—,QA／KA—Induced Increases in Intracellular Free Ca^2＋ in Cultured at Hippocampal Neurons

Objective To examine the effects of Pb2+ on N-methyl-D-aspartate (NMDA)-, K+- and quisqualate(QA)/kainite(KA)-induced increases in intracellular free calcium concentration ([Ca2+]i) in cultured fetal rat hippocampal neurons in order to explain the cognitive and learning deficits produced by this heavy metal. Methods Laser scanning confocal microscopy was used. Results The results clearly demonstrated that adding Pb2+ before or after NMDA/glycine stimulation selectively inhibited the stimulated increases in [Ca2+]i in a concentration-dependent manner. In contrast, Pb2+ treatment did not markedly affect increases in [Ca2+]i induced by an admixture of QA and KA. The minimal inhibitory effect of Pb2+ occurred at 1 μ mol/L, and more than seventy percent abolition of the NMDA-stimulated increase in [Ca2+]iwas observed at 100 μmol/L Pb2+. Evaluation of pb2+-induced increase in [Ca2+]i response to elevating extracellular concentrations of NMDA, glycine or calcium revealed that Pb2+ was a noncompetitive antagonist of both NMDA and glycine, and a competitive antagonist of Ca2+ at NMDA receptor channels. In addition, Pb2+ inhibited depolarization-evoked increases in [Ca2+]i mediated by K+ stimulation (30 μmol/L), indicating that Pb2+ also depressed the voltage-dependent calcium channels. Also, the results showed that Pb2+ appeared to be able to elevate the resting levels of [Ca2+]i in cultured neurons, implying a reason for pb2+-enhanced spontaneous release of several neurotransmitters reported in several previous studies. Conclusion Lead can inhibit NMDA-, K+-, QA/KA-inducod increases in intracellular [Ca2+]i in cultured hippocampal neurons.     

氧化低密度脂蛋白,低氧和5—HT对血管平滑肌细胞5—HT2A受？…

为探讨粥样硬化病变动脉对５－ＨＴ收缩反应增加的机制,观察要样硬化有关因子氧化低密度脂蛋白、低氧、５－ＨＴ对血管平滑肌细胞５－ＨＴ２Ａ受体及其基因表达,以及细胞「Ｃａ＾２＋」ｉ的效应。方法分别将大鼠主动脉平滑肌细胞单独以５０μｇ／ｍｌｏｘＬＤＬ培养８ｈ,２％,低氧处理２４和４８ｈ,１０μｍｏｌ／Ｌ５－ＨＴ处理３０ｍｉｎ,放射配基结合分析测定５－ＨＴ２Ａ受体;ＲＴ－ＰＣＲ和Ｓｏｕｔｈｅｒｎ杂交检测受体     

An increase in intracelluar free calcium ions modulated by cholinergic receptors in rat facial nucleus

Background Ca^2＋ in the central nervous system plays important roles in brain physiology, including neuronal survival and regeneration in rats with injured facial motoneurons. The present research was to study the modulations of intracellular free Ca^2＋ concentrations by cholinergic receptors in rat facial nucleus, and the mechanisms of the modulations.
Methods The fluorescence intensity of facial nucleus in Fluo-3 AM loaded acute brainstem slices was detected by applying intracellular free Ca^2＋ measurement technique via confocal laser scanning microscope. The changes of fluorescence intensity of facial nucleus indicate the average changes of intracellular free Ca^2＋ levels of the neurons.
Results Acetylcholine was effective at increasing the fluorescence intensity of facial nucleus. Muscarine chloride induced a marked increase of fluorescence intensity in a concentration dependent fashion. The enhancement of fluorescence intensity by muscarine chloride was significantly reduced by thapsigargin （depletor of intracellular Ca^2＋ store; P 〈0.01）, rather than Ca^2＋ free artifical cerebrospinal fluid or EGTA （free Ca^2＋ chelator; P〉0.05）. And the increase of fluorescence intensity was also significantly inhibited by pirenzepine （M1 subtype selective antagonist; P 〈0.01） and 4-DAMP （M3 subtype selective antagonist; P 〈0.01）. In addition, fluorescence intensity was markedly increased by nicotine. The enhancement of fluorescence intensity by nicotine was significantly reduced by EGTA, nifedipine （L-type voltage-gated Ca^2＋ channel blocker）, dihydro-β-erythroidine （α4β2 subtype selective antagonist）, and in Ca^2＋ free artificial cerebrospinal fluid （P 〈0.01）, but not in the presence of mibefradil （M-type voltage-gated Ca^2＋ channel blocker） or thapsigargin （P〉0.05）.
Conclusions The data provide the evidence that muscarinic receptors may induce the increase of intracellular free Ca^2＋ levels through the Ca^2＋ release of intracellular Ca^2＋ stores, in a manner related to M1 and M3 subtypes of muscarinic receptors in rat facial nucleus. Nicotine may increase intracellular free Ca^2＋ concentrations via the influx of extracellular Ca^2＋ mainly across L-type voltacle-clated Ca^2＋ channels, in a manner related to the α4β2 subtype of nicotinic receptors.     

Induction of Increased Intracellular Calcium in Astrocytes by Glutamate through Activating NMDA and AMPA Receptors

Almost 90 %ofcellsincentralnervoussystemareglia ,buttheirfunctionsarelittleknown .Whencentralnervoussystemisinjured ,itshowsgliosisnomattertheetiology .Inrecentyears ,manyresearchesrevealthatgliaalso playimportantrolesinnormalphysiologicalactivityandhaveintimaterelationshipwithneurons .Itisevidencedthataclosebidirectionalcommunicationsystemexistsbetweenneuronsandas trocytes[1] .AstrocytescanrespondtotheneurotransmitterreleasedfromactivesynapticterminalswithcytosolicCa2 +elevations ,andinturnc…     

用荧光染料fura-2法测定心室肌细胞内游离钙离子浓度

用fura-2荧光染料测定了静息时的酶解分离心室肌细胞内游离Ca~(2+)浓度,40mMKCI和5mM咖啡因都能使心室肌细胞内游离Ca~(2+)浓度增加,但KCI增加游离Ca~(2+)浓度需要细胞外液中存在Ca~(2+),而咖啡因则否,提示KCl增加细胞内游离Ca~(2+)浓度可能是通过细胞外Ca~(2+)内流,咖啡因则使细胞内贮存Ca~(2+)释放。     

钙激活钾通道在钙离子致神经细胞损伤中的作用

采用膜片钳单通道记录方法,观察原代培养新生ＳＤ大鼠皮层神经元的钙激活钾通道比（Ｋｃａ）特征及胞内不同游离钙水平对通道开放动力学的调节,结果显示：培养ＳＤ大鼠皮层神经元的Ｋｃａ以大电导活动占优势,胞内游离钙为１０＾－８ｍｏｌ／Ｌ时,通道几乎不开放,在１０＾－６ｍｏｌ／Ｌ时达最大激活。由此表明神经元上Ｋｃａ通道开放概率明显依赖于胞浆中钙离子和膜电位,Ｋｃａ对胞内钙离子浓度变化极为敏感,钾通道的开放剂可     

Induction of Increased Intraceilular Calcium in Astrocytes by Glutamate through Activating NMDA and AMPA Receptors

To study the effect of glutamate on the intracellular calcium signal of pure cultured ratastrocytes and the role of NMDA and AMPA receptors in the procedure, the change of calcium sig-nal was investigated by monitoring the fluctuation of intracellular Ca2+ concentration ([Ca2+]i) onthe basis of Fura-2 single cell fluorescent ratio (F345/F380). The changes in the effect of glutamateon the intracellular calcium signal were observed after blockage of NMDA and(or) AMPA recep-tors. It was found that L-glutamate could induce an increased [Ca2+]i in most of the cells in concen-tration- and time-dependent manner. D-(-)-2-amino-5-phosphonopentanoic acid (D-AP-5, a selec-tive antagonist of the NMDA receptor) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, a selec-tive antagonist of the AMPA receptor) could abolish the effects of NMDA and AMPA respectively.Th.e treatment of D-AP-5 and CNQX simultaneously or respectively could attenuate the effect of L-glutamate at varying degrees. All these indicated that glutamate could modulate intracellular Ca2+of pure cultured rat astrocytes through different pathways. The activation of NMDA and AMPA re-ceptors took part in the complex mechanisms.     

三氧化二砷诱导大鼠血管平滑肌细胞凋亡的实验研究

目的探讨三氧化二砷(As2O3)诱导血管平滑肌细胞(VSMCs)凋亡的机制。方法建立大鼠胸主动脉血管平滑肌细胞增殖模型。通过透射电镜、流式细胞仪观察As2O3作用后细胞凋亡形态学和细胞胞浆游离钙离子(Ca^2 )浓度的变化。结果经As2O3处理的VSMCs电镜下呈现凋亡的特征性改变，形态学上表现为细胞胞膜完整、染色质固缩及核碎裂。流式细胞仪分析显示，VSMCs在As2O3作用后出现凋亡峰，而As2O3能通过促进细胞外Ca^2 内流和细胞内Ca^2 池的释放提高胞浆游离Ca^2 浓度。结论As2O3可诱导VSMCs凋亡，并可能与胞浆游离Ca^2 浓度升高有关。     

舒郁胶囊对大鼠海马神经元5-HT3R激活后Ca~(2+)的影响

目的:观察海马神经元内5-羟色胺3受体(5-HT3R)激活后信号通路中Ca2+浓度的变化,探索复方舒郁胶囊治疗抑郁情绪的微观作用机制。方法:培养大鼠海马神经元,在中药血清药理学指导下进行实验:于培养基中添加5-HT3R激动剂激活其介导的信号通路,再以一定浓度舒郁胶囊和柴胡提取物含药血清孵育神经元。采用荧光探针Fluo-3/AM标记结合激光共聚焦显微镜技术测定海马神经元胞内[Ca2+]i。结果:激动剂激活5-HT3R信号通路,神经元胞内[Ca2+]i显著升高(P0.01)。给予正常大鼠舒郁胶囊和柴胡提取物含药血清干预,再次激活信号通路,胞内[Ca2+]i与正常组相比无明显变化,较激动剂组显著降低(P0.05)。结论:舒郁胶囊通过5-HT3R调控海马神经元胞内[Ca2+]i的变化,可能是其治疗抑郁情绪的作用机制之一。