大蒜新素对分离大鼠脑细胞内游离Ca~(2 )的影响

目的:观察大蒜新素对不同刺激剂所致分离大鼠脑细胞内游离钙的影响。方法:以Fura 2-AM为细胞内游离钙的荧光指示剂,用AR-CM-MIC阳离子测定系统,直接测定了分离新生大鼠脑细胞内游离钙([Ca~(2 )]_i)值,观察了大蒜新素的影响。结果:大蒜新素对脑细胞静息[Ca~(2 )]_i无明显影响,大蒜新素1-100μmol·L~(-1)能剂量依赖性地抑制高K~ 和谷氨酸引起的[Ca~(2 )]_i升高,其中IC_(50)分别为59.7和69.9μmol·L~(-1),高剂量大蒜新素100μmol·L~(-1)能抑制去甲肾上腺素引起的[Ca~(2 )]_i升高。结论:大蒜新素对高K~ 、去甲肾上腺素及谷氨酸引起的[Ca~(2 )]_i升高的抑制作用可能是其抗脑缺血作用机制之一。     

TMB-8抑制神经递质引起的单个脑细胞内游离钙的升高(英文)

目的:研究TMB-8对神经递质引起的单个脑细胞内游离钙升高的作用。方法:应用AR-CM-MIC阳离子测定系统测定游离大鼠单个脑细胞内钙离子浓度。结果:当细胞外液Ca~(2 )浓度为1.3mmol·L~(-1)时,TMB-8 30μmol·L~(-1)能降低谷氨酸,组织胺,5-羟色胺引起的脑[Ca~(2 )]_i浓度的升高。而当细胞外液无钙时,TMB-8能降低细胞内静息[Ca~(2 )]_i;TMB-8 10μmol·L~(-1)则几乎完全抑制了组织胺和5-羟色胺引起的脑[Ca~(2 )]_i升高作用。结论:TMB-8能降低谷氨酸,组织胺,5-羟色胺引起的脑[Ca~(2 )]_i升高。     

钾通道开放剂降低血管平滑肌细胞内游离钙浓度(英文)

目的:研究PCO—Pin,Nic,Lem及RP对VMSC内[Ca~(2 )]_i的改变及其可能机制。方法:VSMC加入Fura-2 AM 2.5μmol·L~(-1)37℃下孵育50min,[Ca~(2 )]_i用荧光分光光度计检测。结果:4种PCO能较弱地抑制K~ 30 mmol·L~(-1)诱导的[Ca~(2 )]_i增加,但明显抑制ATP 0.1mmol·L~(-1)诱导的[Ca~(2 )]_i峰相及持续相增加,且呈剂量依赖性。格列苯脲完全阻断Pin,Lem及RP的作用,只部分抑制Nic的作用。无钙液中先给4种PCO,能显著抑制ATP诱导的[Ca~(2 )]_i峰相增加。结论:4种PCO均抑制ATP诱导的[Ca~(2 )]_i增加,此作用与减少细胞外钙内流及细胞内钙释放有关。     

L-焦谷氨酸对抗谷氨酸钠诱发的大鼠皮层神经元损伤

目的:在大鼠皮层神经元研究L-吡咯烷酮羧酸(L-PGA)对谷氨酸钠(Glu)诱发神经毒性的拮抗作用。方法:原代培养的皮层神经元取自16d龄的胎鼠,与Glu作用30分钟,24小时后测定神经元的存活及培养介质中亚硝酸盐的浓度;以Fura 2-AM为细胞内[Ca~(2 )]_i荧光探针,AR-CM-MIC阳离子测定系统测定[Ca~(2 )]_i。结果:L-PGA 10-80μmol·L~(-1)浓度依赖地抑制Glu 500μmol·L~(-1)引起的神经损伤,其IC_(50)为(41±9)μmol·L~(-1),95％可信区间:(30.3-54.7)μmol·L~(-1)。L-PGA也能浓度依赖地降低Glu引起的NO释放。L-PGA 1,3,10,30,100μmol·L~(-1)对Glu 100μmol·L~(-1)引起的[Ca~(2 )]_i升高的抑制率分别为20.5％,34.4％,47.7％,70.6％,80.4％。结论:L-PGA可能通过抑制NO形成或细胞内Ca~(2 )浓度的升高而拮抗Glu的神经毒性。     

小檗胺对高钾、去甲肾上腺素及咖啡因引起大鼠心肌细胞内钙动员的拮抗作用(英文)

目的:研究小檗胺(Ber)对氯化钾、NE及咖啡因引起大鼠培养心肌细胞[Ca~(2 )]_i动员的影响,方法:Fluo 3-AM负载后,共聚焦法测定心肌细胞[Ca~(2 )]_i荧光强度的变化。结果:Ber对心肌细胞静息[Ca~(2 )]_i水平无影响,但可剂量依赖性地抑制KCl60mmol·L~(-1)及NE 30 μmol·L~(-1)引起的内钙动员(P<0.01),此作用与维拉帕米相似.Egtazic acid3 mmol·L~(-1)并不能增强Ber对NE引起的[Ca~(2 )]_i升高的抑制作用,无外钙时,咖啡因80-160μmol·L~(-1)的[Ca~(2 )]_i动员不受Ber的影响(P>0.05),结论:Ber与维拉帕米相似,对大鼠心肌细胞靠电压依赖性和受体操纵性钙通道而升高的胞[Ca~(2 )]_i有拮抗作用,并不影响[Ca~(2 )]_i释放。     

尼卡地平升高小鼠胸腺细胞胞浆钙浓度(英文)

研究尼卡地平(nicardipine,Nic)对小鼠胸腺细胞胞浆钙浓度([Ca~(2 )]_i)及增殖的影响.方法:用Fura-2掺入细胞的荧光测定法测定[ca~(2 )]_i;用[~3H]thymidine掺入法测定胸腺淋巴细胞的增殖.结果:无论在含Ca~(2 )或无Ca~(2 )介质中,Nic 1—30 μmol·L~(-1),以浓度依赖的方式升高静息胸腺细胞的[Ca~(2 )]_i.丝裂原Con A 5 mg·L~(-1)也从细胞内库释放Ca~(2 ),而Nic抑制Con A引起的[Ca~(2 )]_i升高.在上述升高[Ca~(2 )]_i的浓度中,Nic不刺激静息胸腺淋巴细胞增殖,但显著抑制Con A的增殖反应.结论:Nic升高[Ca~(2 )]_i,干扰了细胞Ca~(2 )稳态,因而抑制淋巴细胞对丝裂原的反应.     

钾通道激活剂扩张血管的原理

前言血管扩张的主要原理,被认为与细胞溶质内游离Ca~(2+)浓度降低有关。当Ca~(2+)为0.1μmol/L时,血管平滑肌松弛;当Ca~(2+)为5～10μmol/L时,则这些细胞最大限度收缩。在生理情况下,细胞溶质内游离Ca~(2+)浓度>0.1μmol/L;但维持细胞张力所需要的Ca~(2+)浓度,随着血管组织、部位和种类等不同而异。血管扩张涉及多种过程。例如,电压依     

吗啡戒断后条件性位置厌恶大鼠伏隔核壳区CREB表达

目的:探讨慢性吗啡依赖大鼠纳洛酮催瘾戒断后条件性位置厌恶(conditioned place aversion,CPA)建立、消退和重建过程中,伏隔核壳区(shell of accumbens nucleus,AcbSH)内cAMP反应元件结合蛋白(cyclic-3’,5’adenosine monophosphate response element binding protein,CREB)蛋白表达的适应性变化。方法:(1)连续6 d半每天2次吗啡腹腔注射(10 mg.kg-1.次-1),纳洛酮一次腹腔注射催瘾(0.3 mg.kg-1)搭配训练箱建立CPA,相继对其进行连续7 d(12次,15 min.次-1)消退,然后再经吗啡点燃和纳洛酮催瘾注射搭配训练箱重建CPA。(2)采用免疫组化的方法,于CPA建立后、消退后和重建后不同时间点,检测大鼠AcbSH内CREB的表达情况。结果:(1)慢性吗啡腹腔注射纳洛酮一次腹腔注射催瘾搭配训练箱成功建立CPA大鼠模型,且可被消退和重建。(2)CPA建立后,AcbSH内磷酸化CREB(p-CREB,Ser-133)较对照组表达显著增强(P<0.05);CPA经消退后,p-CREB表达亦相应地显著降低(P<0.01);CPA重建后,p-CREB显著性高表达(P<0.01)。结论:(1)AcbSH可能是慢性吗啡注射纳洛酮催瘾后CPA的重要解剖基础;(2)提示AcbSH内CREB介导的可塑性变化是中枢的情绪状态和强化效应重要的分子机制。     

内吗啡肽抑制苯肾上腺素和血管紧张素Ⅱ诱导的离体大鼠胸主动脉环收缩

目的:研究吗啡、内吗啡肽-1和内吗啡肽-2对由苯肾上腺素(PE)和血管紧张素(Ang)Ⅱ诱导离体大鼠胸主动脉环收缩的抑制作用.方法:离体血管环张力试验.结果:与对照组相比,吗啡、内吗啡肽-1和内吗啡肽-2的预处理(0.1-10μmol/L)能明显降低由PE(0.1μmol/L)和Aug Ⅱ(1μmol/L)(P<0.01)诱导离体大鼠胸主动脉环的张力,但是不能减少去内皮血管的张力.纳络酮(1μmol/L)能部分阻断内吗啡肽-1和内吗啡肽-2的抑制作用(P<0.01),N~(ω)-nitro-L-arginine(10μmol/L)或血管环去内皮能完全阻断这种作用(P<0.01).结论:内吗啡肽-1和内吗啡肽-2通过纳络酮敏感方式抑制由PE和AngⅡ诱导的离体大鼠胸主动脉环收缩,这种抑制作用可能与血管内皮NO的释放有关.     

在地昔帕明诱导胶质瘤C6细胞凋亡过程中caspase 3基因表达和[Ca~(2 )]_i稳态(英文)

目的:研究抗抑郁药地昔帕明(Des)对胶质瘤C6细胞的凋亡诱导作用以及对凋亡关键效应分子caspase3和凋亡早期信号[Ca~(2 )]_i的调控作用.方法:采用流式细胞术(FCM)和凝胶电泳观察Des对C6细胞凋亡的DNA裂解作用,RT-PCR分析。caspase 3基因的表达以及激光扫描共聚焦显微镜测量单个活细胞[Ca~(2 )]_i浓度.结果:Des(10,20,40μmol/L)处理C6细胞24 h后,FCM图的G_1峰左侧出现凋亡特征性亚二倍体细胞峰,凋亡细胞百分率分别为5.2％,21.9％和 41.9％.同时,凝胶电泳显示典型的DNA“梯带”.DeS 20 μmol/L处理C6细胞24 h可明显增强caspase 3基因的表达,而未经Des处理的C6细胞则检测不到caspase 3基因的表达.此外,Des 40 μmol/L可使 C6细胞[Ca~(2 )]_i迅速升高并维持超过28 min,而钙螯合剂依他酸可显著降低C6细胞[Ca~(2 )]_i增高幅度,提示Des致C6细胞[Ca~(2 )]_i增高主要与细胞外钙内流有关.结论:Des诱导C6胶质瘤细胞凋亡可能与caspase 3基因表达的上调以及细胞内钙稳态的失衡有关.     

Opioid receptor antagonists increase [Ca^2＋]i in rat arterial smooth muscle cells in hemorrhagic shock

INTRODUCTION Circulation hypotension induced by hemorrhagicshock is one of the main causes of death after severewounds or trauma. When the hemorrhagic shock hasdeveloped to a decompensatory stage, it is difficult toreverse the hypotension using usual vasoconstrictor,such as norepinephrine. One of the explanations ofhypotension is due to the hyposensitivity of arterialsmooth muscle cells (SMC) to vascular constrictorstimuli[1,2]. Previous studies showed that the vascularhyporesponse was r…     

蚓激酶的心肌保护作用及机制

目的研究蚓激酶对心肌缺血的保护作用，并进一步探讨其可能机制。方法采用结扎大鼠左冠状动脉前降支制备急性心肌缺血模型，观察蚓激酶对心肌缺血的保护作用；应用全细胞膜片钳和激光扫描共聚焦技术，研究蚓激酶对L-型钙电流(I_Ca-L)和细胞内游离钙离子浓度的影响。结果蚓激酶80，40和20 mg·kg^-1剂量组均可缩小心肌梗死面积。膜片钳研究结果表明，当刺激电压为+10 mV时，10和50 μmol·L^-1蚓激酶使I_Ca-L降低共聚焦结果显示，在静息状态下，10 μmol·L^-1蚓激酶对［Ca²⁺］_i无明显影响；但10 μmol·L^-1蚓激酶对60 mmol·L^-1 KCl诱导的［Ca²⁺］_i升高却有明显抑制作用，并且在整个实验过程中(240 s)并未出现明显的峰值。结论蚓激酶对大鼠心肌缺血具有保护作用，其机制可能与抑制I_Ca-L及下调［Ca²⁺］_i有关。     

BAY 41-2272, a potent activator of soluble guanylyl cyclase, stimulates calcium elevation and calcium-activated potassium current in pituitary GH cells

The effects of BAY 41-2272, a nitric oxide-independent activator of soluble guanylyl cyclase, on Ca2+ signalling and ion currents were investigated in pituitary GH3 cells. Intracellular Ca2+ concentrations ([Ca2+]i) in these cells were increased by BAY 41-2272. Removing extracellular Ca2+ abolished the BAY 41-2272-induced increase in [Ca2+]i. After [Ca2+]i was elevated by BAY 41-2272 (300 nmol/L), subsequent application of 1-benzyl-3-(5'-hydroxymethyl-2'-furyl) indazole (YC-1; 1 micromol/L) did not increase [Ca2+]i further. In whole-cell recordings, BAY 41-2272 reversibly stimulated Ca2+-activated K+ current (I(K(Ca))) with an EC50 of 225 +/- 8 nmol/L. At 3 micromol/L, BAY 41-2272 slightly and significantly decreased L-type Ca2+ current.In the cell-attached configuration, BAY 41-2272 (300 nmol/L) enhanced the activity of large-conductance Ca2+-activated K+ (BK(Ca)) channels. After BK(Ca) channel activity was stimulated by spermine NONOate (30 micromol/L) or YC-1 (10 micromol/L) in cell-attached patches, subsequent application of BAY 41-2272 (300 nmol/L) further increased the channel open probability. In the inside-out configuration, BAY 41-2272 applied to the intracellular surface of excised patches enhanced BK(Ca) channel activity. Unlike 1 micromol/L paxilline, 1H-[1,2,4]oxadiazolol-[4,3a] quinoxalin-1-one (ODQ; 10 micromol/L) or heme (10 micromol/L) had no effect on BAY 41-2272-stimulated channel activity. BAY 41-2272 caused no shift in the activation curve of BK(Ca) channels; however, it did increase the Ca2+ sensitivity of these channels. At 300 nmol/L, BAY 41-2272 reduced the firing rate of spontaneous action potentials stimulated by thyrotropin-releasing hormone (10 micromol/L). The BK(Ca) channel activity was also enhanced by 300 nmol/L BAY 41-2272 in neuroblastoma IMR-32 cells. Therefore, the BAY 41-2272-induced increase in [Ca2+]i is primarily explained by an increase in Ca2+ influx. The BAY 41-2272-mediated simulation of IK(Ca) may result from direct activation of BKCa channels and indirectly as a result of elevated [Ca2+]i.     

Tetrandrine inhibits Ca^2＋-activated chloride channel in cultured human umbilical vein endothelial cells

INTRODUCTION Tetrandrine (Tet, 6,6',7,12-tetramethoxy-2,2'- dim-ethyl-berbaman) is a purified bis-benzylisoquinoline al-kaloid derivedfrom the root ofa Chinese herb (Stephaniatetrandra S Moore)[1,2]. It was first shown as an anti-hypertensive agent in both normal and hypertensivesubjects in 1950s[3,4]. The primary anti-hypertensiveaction of Tet is presumably due to its vasodilatoryproperty, which was confirmed both in vivo (15 mg/kg in conscious rats) and in vitro (1-100 μmol/L,effecti…     

Comparative effects of tramadol on vascular reactivity in normotensive and spontaneously hypertensive rats

The aim of the present study was to determine the effects of tramadol on vascular reactivity in aortic rings from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). Aortic rings, with or without endothelium, were obtained from male WKY rats and SHR (15-20 weeks old) and prepared for isometric tension recording. Aortic rings were precontracted with phenylephrine (10 micromol/L) or 40 mmol/L KCl and then exposed to cumulative concentrations of tramadol (0.1-1 mmol/L). Tramadol produced a concentration-dependent relaxation of precontracted aortic rings from WKY rats and SHR, which was not dependent on functional endothelium. Vascular relaxation was significantly greater in rings from SHR than WKY rats. The concentration of tramadol necessary to produce a 50% reduction of the maximal contraction to phenylephrine (IC(50)) in rings with and without endothelium from SHR was 0.47 +/- 0.08 and 0.44 +/- 0.03 mmol/L, respectively (P = 0.76). Tramadol attenuated the contracture elicited by Ca2+ in depolarized tissue, suggesting that it may inhibit L-type Ca2+ channels. However, pretreatment with nicardipine (1 micromol/L) prevented the relaxation induced by tramadol in aortic rings from WKY rats and partially reduced its inhibitory effect in aortic rings from SHR. 6. Pretreatment of endothelium-denuded aorta with glybenclamide (3 micromol/L), 4-aminopyridine (3 mmol/L), tetraethylammonium (3 mmol/L) and naloxone (100 micromol/L) did not affect tramadol-induced vasodilation of aortic rings from either WKY rats or SHR. Intravenous administration of tramadol (10 mg/kg) to conscious SHR significantly reduced both systolic and diastolic blood pressure from 171.4 +/- 5.3 to 129.3 +/- 5.3 (P = 0.002) and from 125.0 +/- 6.5 to 57.8 +/- 8.9 mmHg (P = 0.003), respectively.     

Effect of tetramethylpyrazine on potassium channels to lower calcium concentration in cultured aortic smooth muscle cells

1. Tetramethylpyrazine (TMP) is one of the active principles contained in Ligusticum chuanxiong Hort. (Umbelliferae), a herb that has been used widely in China to treat vascular disorders. 2. In an attempt to elucidate the possible mechanisms of action of TMP, the effect of TMP on intracellular calcium concentrations ([Ca2+]i) was investigated in cultured vascular smooth muscle (A7r5) cells using the Ca(2+)-sensitive dye Fura-2 as an indicator. 3. The increase in [Ca2+]i in A7r5 cells produced by vasopressin (1 micromol/L) or phenylephrine (1 micromol/L) was attenuated by TMP in a concentration-dependent manner. Only inhibitors specific to ATP-sensitive potassium (KATP) channels or small conductance calcium-activated potassium (SKCa) channels attenuated the action of TMP (10 micromol/L) on [Ca2+]i. However, blockers of other K+ channels failed to modify the inhibitory action of TMP (10 micromol/L) on [Ca2+]i. 4. The action of TMP on membrane potential in A7r5 cells was monitored by the fluorescence of bisoxonol. Tetramethylpyrazine caused a concentration-dependent inhibition of changes in membrane potential elicited by KCl (20 mmol/L) or phenylephrine (1 micro mol/L), an effect that was totally reversed by glibenclamide (100 micromol/L) and apamin (100 nmol/L) in combination. 5. The results obtained indicate that the decrease in [Ca2+]i in A7r5 cells produced by TMP is mediated mainly by opening of KATP and/or SKCa channels.     

丹酚酸B镁盐对缺氧复氧内皮细胞内钙和一氧化氮的影响

目的:研究丹酚酸B镁盐对缺氧复氧引起的内皮细胞内钙升高和一氧化氮释放增加的影响.方法:培养的人脐静脉内皮细胞(ECV304)暴露在95％ N_2 5％CO_2条件下缺氧30分钟,后在含5％CO_2的空气中复氧30分钟.内皮细胞的损伤用染料排除实验、SOD的活性和MDA的生成来评价.胞内游离钙浓度用钙荧光探针Fura 2-AM测定.一氧化氮含量用一氧化氮试剂盒测定.内皮型一氧化氮合酶(eNOS)mRNA和诱导型一氧化氮合酶(iNOS)mRNA的表达用半定量逆转录聚合酶链式反应(RT-PCR)检测.结果:缺氧复氧引起内皮细胞的活力由正常条件下(93.1±1.2)％降至(88±3)％(P<0.01),SOD的活性也由(0.24±0.07)kNU/L下降到(0.18±0.03)kNU/L(P>0.05),但其使内皮细胞MDA的生成由(1.12±0.06)mmol/L增至(3.78±0.03)mmol/L(P<0.01).丹酚酸B镁盐2.5,5,10 mg/L能明显降低缺氧复氧引起的内皮细胞MDA生成量的增加,并且显著提高细胞活力和SOD的活性.同时,缺氧复氧还增加内皮细胞的胞内游离钙浓度(F_(340)/F_(380)由 1.65±0.16增至 1.89±0.28)和一氧化氮释放[由(7.5±1.3)μmol/L增至(16±5)μmol/L],并上调其eNOS mRNA的表达,但降低iNOS mRNA的表达(P<0.05).但在无钙的条件下,缺氧复氧对内皮细胞的胞内游离钙浓度、一氧化氮含量、eNOSnRNA和iNOS mRNA表达     

利用体外诱导的钙振荡估测在体内源性物质的生理浓度．肝脏中的情况

AIM: To identify the physiological concentration ranges of norepinephrine (NE), vasopressin (VP), and ATP in the rat liver. METHODS: Rat hepatocytes were isolated by collagenase perfusion. Isolated cells were loaded with the fluorescent calcium indicator Fura-2 acetoxymethyl ester (Fura-2 AM). The effects of different concentrations of norepinephrine, vasopressin, and ATP on intracellular calcium concentration ([Ca2+]i) increases in the freshly isolated rat hepatocytes were investigated. [Ca2+]i was measured by microfluorometry and recorded as fluorescence ratios (F340/F380). RESULTS: NE, VP, and ATP induced increases in [Ca2+]i in a concentration-dependent manner. At lower concentrations, [Ca2+]i tended to show an oscillatory increase; with increasing concentrations, [Ca2+]i in more cells tended to show phasic or plateau increases. NE, VP, and ATP concentrations likely to induce an oscillatory [Ca2+]i response were 100 - 500 nmol/L, 50 - 100 pmol/L, and < 1 micromol/L respectively. CONCLUSION: Physiological concentrations of NE, VP, and ATP are 100 - 500 nmol/L, 50 - 100 pmol/L, and < 1 micromol/L respectively in the rat liver.     

Effects of berbamine on ATP-induced [Ca2+]i mobilization in cultured vascular smooth muscle cells and cardiomyocytes.

AIM: To study the effects of berbamine (Ber) on [Ca2+]i homeostasis induced by adenosine triphosphate (ATP) in vascular smooth muscle cells (VSMC) of rabbits and cardiomyocytes of rats. METHODS: Both cell types were cultured and loaded with Fura 3-AM. [Ca2+]i was measured by fluorescent intensity (FI) in each cell with confocal microscopy. RESULTS: (1) ATP 30 mumol.L-1 elevated [Ca2+]i in VSMC and cardiomyocytes, FI values reached 660 +/- 258 and 1058 +/- 252 from 250 +/- 84 and 218 +/- 76 at 19 s +/- 5 s and 11.8 s +/- 2.4 s, but FI in nucleus was not changed in VSMC. (2) Ber 30 mumol.L-1 did not affect the resting FI in both cell types, but prolonged the time to peak (P < 0.01) and reduced the FI elevated by ATP (P < 0.01), but not completely inhibited even at 100 mumol.L-1. (3) In D-Hanks' solution or in the presence of egtazic acid (EGTA) 3 mmol.L-1, the inhibitory effect of Ber was not seen (P > 0.05). (4) All effects of Ber on ATP-induced [Ca2+]i mobilization were similar to those of Ver 10 mumol.L-1. CONCLUSION: In VSMC and cardiomyocytes, ATP-induced CA2+ influx was inhibited by Ber and Ver, while the Ca2+ release was not.