强啡肽对培养脊髓神经元高钾刺激性胞内钙增高的双向作用

为探讨强啡肽(Dyn)镇痛与致瘫的细胞机理，采用Fura-2显微荧光光度技术观测了不同浓度的Dyn A(1-17)对原代培养脊髓神经元单个细胞内游离钙离子浓度(［Ca²⁺］_i)的影响. Dyn A 0.1-100 μmol·L^-1对基础［Ca²⁺］_i均无影响. Dyn A 0.1和1 μmol·L^-1使高钾(50 mmol·L^-１)刺激的Ca²⁺内流峰值反应分别下降94%(n=6)和83%(n=4, P<0.05); Dyn A 10和100 μmol·L^-1对高钾刺激反应峰值无明显影响，但所有测试细胞均呈现持续性［Ca²⁺］_i升高；预先给予低浓度的Dyn A (0.1和1 μmol·L^-1), 则高浓度Dyn A (10 和100 μmol·L^-1)的促进作用明显 减弱甚至消失. 结果表明低浓度和高浓度Dyn A(1-17)对培养脊髓神经元的基础［Ca²⁺］_i无影响，但可分别抑制和促进去极化性钙离子内流，低浓度Dyn A 可对抗高浓度Dyn A 的促进作用.     

茶黄素对大鼠心室肌细胞内游离钙浓度的影响

目的研究茶黄素对大鼠心室肌细胞内游离钙浓度([Ca2+]i)的影响并探讨其可能机制。方法用激光共聚焦显微镜探测细胞内游离钙浓度,结果用相对荧光强度((FI-FI0)/FI0,%;FI0:对照;FI:给药)表示。结果①茶黄素(10,20,40μmol.L-1)对正常台氏液中心肌细胞内游离钙浓度没有影响,却可浓度依赖性地降低模拟缺血液中心室肌细胞[Ca2+]i的增加。②预先应用L型钙通道开放剂Bay k8644,可大部分取消茶黄素(20μmol.L-1)在模拟缺血液中的作用。③茶黄素(20μmol.L-1)能明显抑制无钙台氏液中由低浓度ryanodine引起的[Ca2+]i增加。④当细胞外液钙浓度由1 mmol.L-1增加到10 mmol.L-1而诱发心室肌细胞钙超载时,部分心室肌细胞产生可传播的钙波,茶黄素(20μmol.L-1)可降低钙波发生的频率和持续时间,最终阻断钙波并降低[Ca2+]i。结论茶黄素可抑制电压门控性钙通道的外钙内流和减少肌浆网的内钙释放从而降低[Ca2+]i。     

Properties of intracellular calcium stores in pregnant rat myometrium

1. The properties of the Ca2+ stores in myometrium of 21-day pregnant rats were studied by recording the contractile responses of saponin-treated skinned muscles. 2. After accumulation of Ca2+ into the stores in the presence of 5 mM NaN3, inositol 1,4,5-trisphosphate (InsP3) at concentrations exceeding 3 microM produced a contraction. The amplitude of this contraction was maximal at about 20 microM. A second application of 20 microM InsP3 produced a smaller contraction than the first one. However after reloading the stores with Ca2+, 20 microM InsP3 produced a contraction of the same amplitude as the initial one. 3. After application of 20 microM InsP3, 1 microM A23187 still evoked a large contraction. If A23187 was applied first, the subsequent application of InsP3 or A23187 no longer induced a contraction, even after Ca2+ loading. 4. Guanosine triphosphate (GTP) or arachidonic acid, both 100 microM neither evoked a contraction nor enhanced the subsequent contraction elicited by 20 microM InsP3. 5. Caffeine 25 mM did not induce a contraction nor did it affect the contraction elicited by 20 microM InsP3. 6. The results indicate that in pregnant rat myometrium InsP3 releases Ca2+ from intracellular stores as has been proposed in vascular smooth muscles.     

The intracellular calcium stores in the rabbit trachealis

We investigated the role of the intracellular Ca2+ stores in the regulation of the rabbit tracheal smooth muscle contraction. Carbachol (10 microM)- and 80K-induced contractions were reduced by preincubating tissues in Ca2+-free (EGTA-PSS) solution. Contractile amplitude plotted as a function of the duration of EGTA-PSS preexposure was described by a biexponential for carbachol and a monoexponential for 80K. In EGTA-PSS, a prior caffeine (50 mM)-induced contraction prevented any subsequent phasic carbachol response; the converse was also true. In contrast, prior exposure to 80K increased the amplitude of a subsequent carbachol or caffeine contraction measured in EGTA-PSS. Repletion of Ca2+ plus either 80K or a low concentration of carbachol (0.3 microM) resulted in delayed tension development. Preincubation in forskolin (10(-5) M) in PSS also delayed tension development. We propose that the internal stores, most likely the sarcoplasmic reticulum in the airway muscle function both to supply and remove Ca2+ from the cytoplasm.     

强啡肽对培养脊髓神经元高钾刺激性胞内钙增高的双向作用

为探讨强啡肽（Ｄｙｎ）镇痛与致瘫的细胞机理，采用Ｆｕｒａ－２显微荧光光度技术观测了不同浓度的ＤｙｎＡ（１－１７）对原代培养脊髓神经元单个细胞内游离钙离子浓度（［Ｃａ２＋］ｉ）的影响．ＤｙｎＡ０．１－１００μｍｏｌ·Ｌ－１对基础［Ｃａ２＋］ｉ均无影响．ＤｙｎＡ０．１和１μｍｏｌ·Ｌ－１使高钾（５０ｍｍｏｌ·Ｌ－１）刺激的Ｃａ２＋内流峰值反应分别下降９４％（ｎ＝６）和８３％（ｎ＝４，Ｐ＜０．０５）；ＤｙｎＡ１０和１００μｍｏｌ·Ｌ－１对高钾刺激反应峰值无明显影响，但所有测试细胞均呈现持续性［Ｃａ２＋］ｉ升高；预先给予低浓度的ＤｙｎＡ（０．１和１μｍｏｌ·Ｌ－１），则高浓度ＤｙｎＡ（１０和１００μｍｏｌ·Ｌ－１）的促进作用明显减弱甚至消失．结果表明低浓度和高浓度ＤｙｎＡ（１－１７）对培养脊髓神经元的基础［Ｃａ２＋］ｉ无影响，但可分别抑制和促进去极化性钙离子内流，低浓度ＤｙｎＡ可对抗高浓度ＤｙｎＡ的促进作用．     

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。     

Effect of taurine on intracellular free calcium concentration in cultured neonatal rat heart cells

在培养的单个ＳＤ乳鼠心肌细胞，观察了牛磺酸对ＫＣｌ，去甲肾上腺素（ＮＥ）和毒毛花苷Ｇ引起的胞浆游离Ｃａ２＋浓度（［Ｃａ２＋］ｉ）变化的影响．当细胞外ＣａＣｌ２浓度为１．３ｍｍｏｌ·Ｌ－１时，牛磺酸１０，２０ｍｍｏｌ·Ｌ－１不影响心肌细胞静息［Ｃａ２＋］ｉ；但能浓度依赖性地抑制３５ｍｍｏｌ·Ｌ－１ＫＣｌ和１μｍｏｌ·Ｌ－１毒毛花苷Ｇ升高［Ｃａ２＋］ｉ的作用．１０μｍｏｌ·Ｌ－１ＮＥ在含Ｃａ２＋的缓冲液中能引起双相的［Ｃａ２＋］ｉ变化，即快速升高相和持续升高相．牛磺酸２０ｍｍｏｌ·Ｌ－１能抑制ＮＥ引起的［Ｃａ２＋］ｉ持续升高，而对快速升高相无显著影响．在无Ｃａ２＋的缓冲液中，牛磺酸不影响ＮＥ升高［Ｃａ２＋］ｉ的作用．结果提示牛磺酸可能通过减少心肌细胞电压依赖性Ｃａ２＋内流和Ｎａ＋／Ｃａ２＋交换而抑制ＫＣｌ，ＮＥ和毒毛花苷Ｇ引起的［Ｃａ２＋］ｉ升高．     

牛磺酸对培养乳鼠心肌细胞胞浆游离钙浓度的影响

在培养的单个SD乳鼠心肌细胞,观察了牛磺酸对KCl, 去甲肾上腺素(NE)和毒毛花苷G引起的胞浆游离Ca^２＋浓度(［Ca^２＋］_i)变化的影响. 当细胞外CaCl₂浓度为1.3 mmol·L^-１时, 牛磺酸10, 20 mmol·L^-１不影响心肌细胞静息［Ca^２＋］_i; 但能浓度依赖性地抑制35 mmol·L^-１ KCl和1 μmol·L^-１毒毛花苷G升高［Ca^２＋］_i的作用.10 μmol·L^-１ NE在含Ca^２＋的缓冲液中能引起双相的［Ca^２＋］_i变化, 即快速升高相和持续升高相.牛磺酸20 mmol·L^-１能抑制NE引起的［Ca^２＋］_i持续升高, 而对快速升高相无显著影响. 在无 Ca^２＋ 的缓冲液中, 牛磺酸不影响NE升高［Ca^２＋］_i的作用. 结果提示牛磺酸可能通过减少心肌细胞电压依赖性Ca^２＋内流和Na⁺/Ca^２＋交换而抑制KCl, NE和毒毛花苷G引起的［Ca^２＋］_i升高.     

The role of intracellular calcium stores in motilin induced contractions of the longitudinal muscle of the rabbit duodenum

Summary The contraction of longitudinal muscle strips of the rabbit duodenum in response to motilin and acetylcholine was investigated in normal and high K⁺-solutions in the presence and absence of external calcium, in order to demonstrate the existence of pharmaco-mechanical coupling for motilin and to examine whether the peptide mobilizes calcium from an intracellular store. In depolarized smooth muscle (140 mM K⁺), motilin (3.2×10⁹ –1×10^–7 M) and acetylcholine (1×10^–5 M) were still capable of causing a considerable, transient, concentration-dependent contraction in the presence of Ca²⁺. The extra-contraction to motilin was not blocked by tetrodotoxin (1 g/ml) nor by atropine (10^–7 M), but acetylcholine (10^–5 M) was blocked by atropine. Verapamil (10^–7 M) could selectively block the K⁺ contraction without affecting the extra agonist contraction. Nitroprusside was ineffective up to 10^–4 M in high K⁺-solutions, but in normal Hepes-buffer it caused a concentration-dependent rightward shift of the concentration-response curve of motilin and acetylcholine contractions. In a calcium-depleted medium, high K⁺-depolarized muscle strips were still responsive to motilin and acetylcholine, but higher concentrations (10^–6 M) were needed than in the presence of calcium and the contractions reached only 57 +- 11% and 74 +- 9% respectively of the maximal contraction in 1.2 mM Ca²⁺ containing solutions. The response to motilin (10^–6 M) was not only smaller than that to acetylcholine (10^–5 M), it also faded more rapidly with time. The response to one agonist could not be repeated except by using a higher concentration of the same or the other agonist, and the magnitude of this second response depended upon the dose used in the first one. We conclude that pharmaco-mechanical coupling exists for motilin and that this peptide is able to elicit contractions by mobilization of calcium from an intracellular store. This store overlaps with the one used by acetylcholine. Our experiments also reinforce the hypothesis that in the rabbit motilin exerts a direct action upon smooth muscle cells.     

Menadione inhibits the alpha 1-adrenergic receptor-mediated increase in cytosolic free calcium concentration in hepatocytes by inhibiting inositol 1,4,5-trisphosphate-dependent release of calcium from intracellular stores.

In order to establish the mechanism of perturbation of hormonally regulated calcium homeostasis in hepatocytes caused by menadione, the effects of menadione on hepatic alpha 1-adrenergic receptors and on alpha 1-adrenergic receptor-mediated increase in cytosolic free calcium concentration were determined. Menadione had no detectable effect on the alpha 1-adrenergic receptor but significantly inhibited (-)-epinephrine-dependent increases in intracellular free calcium concentration in Quin2 acetoxymethyl ester-loaded hepatocytes. The hormonally induced increase in intracellular free calcium concentration is caused by formation of inositol 1,4,5-trisphosphate (IP3) which binds to a specific receptor and causes a release of intracellular ATP-dependently sequestrated calcium. The IP3-stimulated release of calcium from intracellular pools in hepatocytes was inhibited to a great extent after treatment with menadione. This inhibition could also be observed after treatment of hepatocytes with p-benzoquinone and N-ethylmaleimide and could not be reversed by the thiol-reducing reagent dithiothreitol which indicated covalent binding to an essential free sulfhydryl group. The inhibition of IP3-dependent release of intracellular calcium was accompanied by a large increase in the number of detectable IP3 receptors without any change in the dissociation constant as determined in permeabilized hepatocytes. The increase in IP3 receptors caused by menadione could be reversed by dithiothreitol which suggests the involvement of free sulfhydryl groups. It is concluded that the IP3 receptor plays an important role in the mechanism of menadione-induced perturbation of hormonally regulated calcium homeostasis in rat hepatocytes.     

激光共聚焦扫描显微镜技术在大鼠皮层神经元细胞内钙离子浓度动态测定中的应用

目的探讨激光共聚焦扫描显微镜(LCSM)技术在动态测定神经元细胞内钙离子浓度中的应用。方法采用原代培养大鼠皮层神经元,用LCSM测定给KCl前后细胞内钙离子浓度的动态变化。结果培养神经元状态良好,用LCSM准确、稳定、可靠地测出细胞内钙离子浓度的动态变化。结论LCSM在动态测定神经元细胞内钙离子浓度中具有明显优势。     

Effect of tributyltin chloride on the release of calcium ion from intracellular calcium stores in rat hepatocytes.

The effects of tri-n-butyltin chloride (TBT), an environmental pollutant, on the release of Ca(2+) from intracellular stores were investigated in isolated rat hepatocytes. Isolated hepatocytes permeabilized with digitonin were suspended in solution, and the concentration of extracellular Ca(2+) was measured, using a fluorescent Ca(2+) dye, fura-2. In the solution containing permeabilized hepatocytes that had been preincubated with 4.0 microM TBT for 30 min, the extracellular Ca(2+) concentration was high, but the inositol 1,4,5-trisphosphate (InsP(3))-induced increase in Ca(2+) concentration was suppressed, suggesting that the extracellular release of Ca(2+) in response to TBT treatment was from intracellular stores. Images of the Ca(2+) concentration in the intracellular stores of primary cultured hepatocytes loaded with fura-2 were obtained after digitonin-permeabilization, using digitalized fluorescence microscopy. The permeabilized hepatocytes that had been preincubated with 4.0 microM TBT for 30 min had a very low fura-2 fluorescence ratio (340/380 nm), suggesting that stored Ca(2+) was released. When the hepatocytes were treated with 4.0 microM TBT after digitonin-permeabilization, the decrease in the fura-2 fluorescence ratio was very small. However, when the permeabilized hepatocytes were incubated with 4.0 microM TBT and 2.0 microM NADPH, the decrease was enhanced, raising the possibility that TBT might be metabolized to the active form(s), thus releasing Ca(2+) from intracellular stores. When the hepatocytes were preincubated with 0.1 microM TBT for 30 min and then were permeabilized, the fura-2 fluorescence ratio was almost the same as that in the control permeabilized hepatocytes. However, the InsP(3)-induced decrease in the fluorescence ratio was suppressed significantly in the permeabilized hepatocytes. These results suggest that TBT released Ca(2+) from the intracellular stores at high concentrations, and suppressed the InsP(3)-induced Ca(2+) release at non-toxic low concentrations. It is probable that the latter effect was responsible for the previously reported suppression of Ca(2+) response induced by hormonal stimulations (Kawanish et al., Toxicol Appl Pharmacol 1999;155:54-61).     

Effects of brazilin on the phospholipase A2 activity and changes of intracellular free calcium concentration in rat platelets

Brazilin {7,11 b-dihydrobenz[b]indeno[1,2-d]pyran-3,6a,9,10(6H)-tetrol} inhibited thrombin-, collagen-and ADP-induced aggregation of washed rat platelets. Thrombin- and collagen-induced ATP release were also inhibited by brazilin in a concentration-dependent manner. Brazilin inhibited the formation of platelet thromboxane A₂ caused by thrombin, whereas it had no effect on the prostaglandin D₂ formation. Brazilin inhibited [³H]-arachidonic acid liberation from membrane phospholipids of thrombin-stimulated platelets. Brazilin inhibited the rise of intracellular free calcium caused by thrombin. These results indicate that the inhibition of phospholipase (PLA₂) activity and [Ca²⁺]_i elevation might be at least a part of antiplatelet mechanism of brazilin.     

Central role of intracellular calcium stores in acute flow- and agonist-evoked endothelial nitric oxide release

1. We have used a cascade bioassay system and isolated arterial ring preparations to investigate the contribution of Ca²⁺ release from endothelial intracellular stores to nitric oxide (NO) production evoked by increases in shear stress and by acetylcholine in rabbit aorta.
2. Experiments were performed before and following incubation with either the endoplasmic reticulum Ca²⁺-ATPase inhibitors cyclopiazonic acid (CPA, 10 μM) and thapsigargin (TSG, 1 μM) or ryanodine (30, 100 μM) which binds to a specific endoplasmic reticulum Ca²⁺-release channel.
3. In cascade bioassay all three agents induced relaxations of the recipient ring (CPA, 24.4±3.8%; TSG, 51.5±10.6%; ryanodine, 17.4±1.6%) which were significantly attenuated by preincubation of the donor with 100 μM N^G-nitro-L-arginine methyl ester (L-NAME). However, in isolated rings, only CPA and TSG induced L-NAME-sensitive relaxations (CPA 52.7±6.5%; TSG 61.3±7%).
4. Addition of superoxide dismutase (SOD) to the donor perfusate evoked relaxations of the recipient ring in cascade bioassay (13.3±1.4%, n=22). Prior administration of SOD attenuated relaxations to TSG (23.2±3.8%, n=4) and ryanodine (1.7±0.8%, n=4), and pre-incubation with TSG and ryanodine blunted SOD-induced responses (4±1.5%, n=4 and 8.9±1.1%, n=4, respectively). By contrast, no interaction was observed between the relaxations evoked by SOD and CPA. In isolated rings, SOD exerted no direct relaxant action and did not modulate relaxations to CPA, TSG or ryanodine.
5. In cascade bioassay studies time-averaged shear stress was manipulated with dextran (1–4% w/v, 80000 MW) to increase perfusate viscosity. NO-dependent relaxation of the recipient ring induced by increased perfusate viscosity was significantly attenuated by CPA (P<0.01; n=6) and TSG (P<0.05; n=7), but not by ryanodine (n=6).
6. Endothelium-dependent relaxations to acetylcholine (0.1–30 μM) in cascade bioassay and in isolated aortic ring preparations were markedly attenuated by pretreatment with CPA and TSG, but were unaffected by ryanodine. Ryanodine and CPA caused only a small attenuation of endothelium-independent relaxations to sodium nitroprusside (0.001–10 μM), whereas TSG had no effect.
7. We conclude that release of Ca²⁺ from CPA- and TSG-sensitive endothelial stores is necessary for NO release evoked by acute flow changes and agonists in rabbit abdominal aorta. Ca²⁺-induced Ca²⁺ release via the ryanodine-sensitive release channel plays no direct role in these responses. Free radical interactions may complicate the interpretation of findings in cascade bioassay compared with isolated ring preparations.

     

Low concentrations of caffeine raise intracellular calcium concentration only in the presence of extracellular calcium in cultured molluscan neurons

• 1.1. The effects of low concentrations of caffeine (100 and 300 μM) on the intracellular calcium concentration [Ca²⁺]_i in four cultured, identified neurons of the pond snail Lymnaea stagnalis (L) were investigated.
• 2.2. Intracellular CA²⁺ levels in these neurons were measured with the cell-permeable Ca²⁺ indicator Fura-2/AM, both in the presence and absence of extracellular Ca²(O-Ca²⁺/EGTA).
• 3.3. In the presence of Ca²⁺ in the external medium, caffeine was found to induce a substantial elevation in the free [Ca²⁺]_i in all cell types.
• 4.4. In some cases, the rise in [Ca²⁺]_i was found to be both time- and concentration-dependent.
• 5.5. Low doses of caffeine did not produce any appreciable rise in [Ca²⁺]_i in the absence of Ca²⁺ in the external medium, but calcium was still available from stores, as clinical concentrations of halothane rose [Ca²⁺]_i in the absence of extracellular calcium.
• 6.6. These results indicate that the actions of caffeine, when applied at low concentrations, are dependent on extracellular calcium.

     

Elevation of intracellular cyclic AMP concentration fails to inhibit adrenaline-induced hyperpolarization in amphibian sympathetic neurons.

1. The effect of drugs on the adenosine 3':5'-cyclic monophosphate (cyclic AMP) content of desmethylimipramine (DMI)-treated bullfrog paravertebral sympathetic ganglia was studied by radioimmunoassay. The adrenaline-induced hyperpolarization (Adh) in the tissue was recorded by means of the sucrose-gap technique. 2. In the presence of propranolol (1 microM) and DMI (0.5 microM), adrenaline (1 microM) significantly reduced the concentration of cyclic AMP in forskolin-treated ganglia. This effect was prevented by pertussis toxin (5 micrograms ml-1). 3. The relative potency for drugs which increased ganglionic cyclic AMP content was: 50 microM forskolin much greater than 5 mM fluoride greater than 2 mM fluoride greater than 2 mM isobutylmethylxanthine (IBMX) greater than 5 mM caffeine. In contrast, their relative potency for inhibition of the Adh was: 2 mM IBMX greater than 5 mM fluoride greater than 5 mM caffeine much greater than 2 mM fluoride greater than 50 microM forskolin. The Adh was unaffected by pertussis toxin (5 micrograms ml-1). 4. Although the Adh was slightly reduced by the extracellular application of 8-bromo (8-Br) cyclic AMP, the majority of the data suggest that the transduction mechanism underlying the Adh is independent of the intracellular cyclic AMP concentration and provide an example of an alpha 2-adrenoceptor-mediated response that occurs independently of inhibition of adenylate cyclase.     

ATP对大鼠三叉神经节小直径神经元胞内钙浓度的调制作用及其机制

目的探讨神经递质ATP通过何种途径引起大鼠三叉神经节(trigeminal ganglion,TG)小直径神经元胞内钙离子浓度升高。方法在急性分离的TG神经元上,应用钙离子成像技术检测胞内游离Ca2+浓度([Ca2+]i)的变化。结果在大鼠TG小直径神经元中,ATP(100μmol·L-1),thap-sigargin(1μmol·L-1,内质网钙泵抑制剂)和咖啡因(20mmol·L-1,内质网钙离子通道开放剂)在正常细胞外液和去除细胞外Ca2+的情况下,均能够引起细胞[Ca2+]i升高。在细胞外无Ca2+条件下,thapsigargin能够可逆地抑制ATP引起细胞内[Ca2+]i升高(n=8,P<0.01),而咖啡因对ATP引起的细胞内[Ca2+]i升高无影响(n=6,P>0.05)。然而在正常外液中,thapsigargin不能完全抑制ATP引起的细胞内[Ca2+]i升高,不过ATP引起的细胞内[Ca2+]i升高的幅度明显地低于thapsigargin处理前(n=7,P<0.05)。结论在大鼠TG小直径神经元中,存在有IP3敏感钙库和Ryanod-ine敏感钙库。ATP可通过激动P2Y受体引起IP3敏感钙库的Ca2+释放,也可通过激动P2X受体引起细胞外钙内流。     

Regulation by thapsigargin and carbachol of the intracellular calcium concentration in rat submandibular glands

• 1.1. Carbachol and thapsigargin both increased the intracellular calcium concentration in rat submandibular cells in the presence and in the absence of extracellular calcium. Depletion of intracellular calcium pools with thapsigargin prevented the response to carbachol.
• 2.2. The two agents also increased the influx of calcium. The muscarinic agonist stimulated the efflux of calcium outside the cell.
• 3.3. From these results it is concluded that submandibular cells posses several intracellular calcium pools sensitive to thapsigargin, among which some are sensitive to IP₃. Depletion of these pools increase the uptake of extracellular calcium.

     

茅莓总皂苷对大鼠海马神经元细胞缺氧损伤后胞内钙超载的影响

目的研究茅莓总皂苷对原代培养大鼠海马神经元缺血损伤后胞内钙超载的影响。方法大鼠海马神经元培养后,用Fluo-2/AM负载培养的神经细胞,氧糖剥夺30min,在激光共聚焦显微镜下监测加入茅莓总皂苷后海马神经元的[Ca2+]i的变化。结果茅莓总皂苷10-5,10-4,10-3g·L-1和Nim10-5mol·L-1组能不同程度地降低大鼠海马神经元细胞内[Ca2+]i。结论茅莓总皂苷可通过减轻细胞内的钙超载来对缺血神经元进行保护。