金丝桃苷对新生大鼠神经细胞缺氧/再给氧损伤的保护作用及其机制

目的探讨金丝桃苷(hyperin,Hyp)对新生大鼠脑细胞缺氧/再给氧损伤的保护作用及其机制。方法将分离的新生大鼠脑细胞缺氧30min或缺氧30min后再给氧40min造成细胞缺氧或再给氧损伤模型,测定细胞培养上清液中乳酸脱氢酶(LDH)、丙二醛(MDA)和一氧化氮(NO)水平的变化,用Fura2-AM方法测定脑细胞内游离钙离子浓度([Ca2+]i)的变化。结果脑细胞缺氧时,细胞培养上清液中LDH从(62.0±13.0)U·L-1(Sham组)增高到(116.0±16.6)U·L-1(Control组,P<0.01),再给氧时,LDH和MDA分别从(45.6±9.2)U·L-1和(9.1±0.9)μmol·L-1(Sham组)增高到(106.0±17.4)U·L-1和(16.4±2.7)μmol·L-1(Control组,P<0.01)。Hyp在1.0～16.0μmol·L-1范围内,明显地抑制缺氧及再给氧损伤诱导的上述LDH和NO增高,并呈一定的浓度依赖性。1.0～16.0μmol·L-1的Hyp不仅可明显地抑制缺氧诱导的细胞培养上清液中NO和脑细胞内[Ca2+]i的增高(P<0.05或P<0.01),也可明显地抑制再给氧时NO和脑细胞内[Ca2+]i的升高(P<0.05或P<0.01),16.0μmol·L-1的Hyp可将再给氧时NO和[Ca2+]i分别从(34.4±6.3)μmol·L-1和(640±94)nmol·L-1(Control组)降至(25.0±5.1)μmol·L-1(P<0.05)和(331±56)nmol·L-1(P<0.01)。结论Hyp对神经细胞缺氧/再给氧损伤保护作用可能与抑制NO的释放、钙超载及自由基脂质过氧化有关。     

溶血磷脂酰胆碱刺激脑微血管平滑肌细胞增殖的细胞内信号转导途径

通过测定 [3 H]胸腺嘧啶核苷 ( [3 H]Td R)参入和结晶紫染色法测定平滑肌细胞增殖 ,研究了溶血磷脂酰胆碱 ( LPC)刺激牛脑微血管平滑肌细胞( BCMSMC)增殖的细胞内信号转导途径 .结果显示 ,LPC能浓度依赖性 ( 1 nmol· L-1- 1 0μmol·L-1)诱导 BCMSMC摄取 [3 H]Td R,在 LPC的浓度为 1 0μmol· L-1时作用达最大 ,cpm由 366± 1 42升至 1 761± 2 96( P<0 .0 1 ) ;LPC亦能浓度依赖性( 1 nmol· L-1- 1 0μmol· L-1)诱导 BCMSMC增殖 ,在 LPC浓度为 1 μmol· L-1时促增殖作用达坪值 ,A595nm由 0 .0 60± 0 .0 0 9增至 0 .1 0 0± 0 .0 1 5( P<0 .0 1 ) .丝裂原激活蛋白激酶 ( MAPK)特异性抑制剂 PD980 59( 2 - 50 μmol· L-1) ,血小板衍生生长因子受体抑制剂酪氨酸磷酸化抑制剂 AG 1 2 96( 2 -50 μmol· L-1)以及蛋白质酪氨酸激酶抑制剂除莠霉素 A( 2 - 1 0μmol· L-1)能浓度依赖性地抑制LPC的上述作用 .表明 LPC能促进 BCMSMC增殖 ,其细胞内信号转导与 MAPK途径有关 .     

细胞内游离钙在辛伐他汀诱导大鼠血管平滑肌细胞凋亡中的作用

目的　研究 3 羟 3 甲戊二酰辅酶A (HMG CoA)还原酶抑制剂辛伐他汀诱导血管平滑肌细胞(VSMC)凋亡的机制。方法　以荧光染料Fura 2 /AM负载后荧光分光光度计法检测细胞内游离钙浓度 ,以DNA琼脂糖凝胶电泳、流式细胞仪PI/膜联蛋白 (an nexin)V染色及半胱天冬酶 3激活来检测细胞凋亡。结果　辛伐他汀 30 μmol·L- 1孵育VSMC后 ,细胞内游离钙浓度显著升高 ,6h时达对照的 3倍以上 (P <0 .0 1) ,维拉帕米 80 μmol·L- 1与辛伐他汀 30 μmol·L- 1共同孵育VSMC 6h后细胞内游离钙浓度为 (14 4± 34)nmol·L- 1(P <0 .0 1)。辛伐他汀可诱导细胞凋亡率增高、“DNA梯状”样改变及半胱天冬酶 3的激活 ,这些变化均可被维拉帕米所逆转。结论辛伐他汀通过使细胞外钙大量内流而诱导VSMC凋亡。     

心肌细胞缺氧时肌浆网钙泵活力变化及药物作用

用培养乳鼠心肌细胞加代谢抑制剂Retenone制成心肌缺氧模型，心肌细胞缺氧50分钟时肌浆网上钙泵活力明显下降，心肌细胞搏动频率下降（P＜0．01）。加入L-型钙通道拮抗剂Lacidipine使肌浆网钙泵活力上升，心肌细胞搏动频率增加（P＜0．05）。提示心肌细胞缺氧时肌浆网钙系功能下降可能是心肌细胞缺氧损伤的重要因素。     

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。     

碘化N-正丁基氟哌啶醇对大鼠心肌细胞内钙离子的影响

目的:研究碘化N-正丁基氟哌啶醇(F2)对大鼠心肌细胞内钙离子([Ca2+]i)的影响。方法:采用钙荧光染料Fluo-3-AM负载心肌细胞,在激光扫描共聚焦显微镜上测定细胞内钙离子的变化。结果:在含钙(1.8mmol·L-1)台式液中,60mmol·L-1KCl使细胞内钙荧光强度由1.0增高至1.84±0.35(P<0.01,n=50),分别用0.1、1、10μmol·L-1F2预先孵育心肌细胞,F2可以浓度依赖地抑制钙荧光强度的增高,IC50为1.61μmol·L-1。0.1、1、10μmol·L-1F2使得KCl诱导增高的钙荧光强度从1.92±0.42分别降至1.88±0.39、1.31±0.36和1.09±0.05(P分别>0.05、<0.01和<0.01,n=50),IC50为1.78μmol·L-1。F2不影响静息状态下的细胞内钙的浓度。对咖啡因和三磷酸肌醇介导的细胞内钙的释放均无作用。结论:F2通过阻断心肌细胞膜电压依赖性钙通道降低心肌细胞内钙浓度,这可能是保护心肌缺血/再灌注损伤的机制。     

大鼠心肌多胺代谢限速酶ODC、SSAT活性分析

目的建立大鼠心肌多胺代谢限速酶鸟氨酸脱羧酶(ODC)及精脒/精胺乙酰转移酶(SSAT)活性分析方法。方法以Langendorff离体灌流心肌为实验材料,制备心肌组织匀浆;分别以dl[114C]Ornithine及[114C]acetylCoenzymeA为底物,以液体闪烁计数仪记录生成的14CO2及[14C]acetylspermidine的放射活度,并以其代表ODC,SSAT的活性;计算大鼠心肌ODC、SSAT的酶促反应动力学参数,筛选出适宜的底物浓度;同时观察一氧化氮(NO)供体硝普钠(SNP)对酶活性的影响。结果①大鼠心肌ODC、SSAT基础活性分别为:(9.67±3.09)nmol·mg-1Pro·h-1;(3.59±0.91)nmol·mg-1Pro·min-1。②ODC催化LOrnithine的酶促反应动力学参数Km=(54.95±8.14)μmol·L-1;Vmax=(2.364±0.37)nmol·mg-1·h-1;SSAT催化AcetylCoenzymeA的酶促反应动力学参数Km=(12.87±1.88)μmol·L-1;Vmax=(0.50±0.07)nmol·mg-1·min-1。③大鼠心肌ODC、SSAT活性检测的底物浓度分别为:90μmol·L-1(18.5kBq)DL[114C]Ornithine及36μmol·L-1(2.96kBq)[114C]acetylCoA。④SNP呈浓度依赖性地抑制ODC的活性、诱导SSAT的活性。结论建立了大鼠心肌多胺代谢限速酶鸟氨酸脱羧酶(ODC)及精脒/精胺乙酰转移酶(SSAT)活性的分析方法,该方法简便易行;根据Km值确定测定大鼠心肌ODC及SSAT?     

熊去氧胆酸选择性诱导人肝肿瘤细胞凋亡及抑制增殖的实验研究

目的: 探讨熊去氧胆酸 (UDCA)对肝肿瘤细胞株诱导凋亡及抑制增殖的作用和机制。方法:用四氮唑蓝法、流式细胞术、TUNEL法、Wright Giemsa染色法、电镜及免疫细胞化学等方法,观察UDCA对肝肿瘤细胞株HepG2,BEL7402和正常人肝细胞株L 02的生长活力、细胞凋亡、细胞周期及Bax/bcl 2表达的影响。结果: UDCA对HepG2,BEL7402细胞株生长的抑制作用随药物浓度增高而增强(r2 =0. 96, P<0. 01;r2 =0. 97, P<0. 01;48h)。UDCA对HepG2及BEL7402的IC50分别为0. 92 mmol·L-1, 0. 86 mmol·L-1。UDCA(1. 0mmol·L-1 )对HepG2及BEL7402的凋亡率分别为(42±6) %及 (44±4) %,明显高于对照组(P<0. 01),并且阻滞细胞周期于S期。以UDCA(0. 8mmol·L-1 )处理HepG2 后bcl 2 表达由(24. 3±2. 4) %降低为 (10. 1±1. 6 ) %,Bax表达由(43±5) %升高为 (59±3) % (P<0. 01 );处理BEL7402细胞后bcl 2表达由 (21. 6±1. 8) %降为(11. 6±2. 1) %,Bax表达由 ( 44±4 ) %升高为(59±3) % (P<0. 01)。UDCA对L 02细胞无明显作用。结论: UDCA对HepG2, BEL7402细胞株有显著的抑制增殖及诱导凋亡作用,它可能与UDCA阻滞细胞周期、降低bcl 2和提升Bax的表达有关。     

庆大霉素对人肾小管上皮细胞系(HK-2)热休克蛋白(HSP)70表达的影响

目的观察了庆大霉素在体外对肾小管上皮细胞内HSP70表达的影响。方法将庆大霉素(100mg·L-1)作用于人肾小管上皮细胞系(HK-2),用MTT法检测庆大霉素对HK-2细胞增殖活力的影响,应用免疫细胞化学和Westernblot法观察了HSP70蛋白表达的改变,采用RT-PCR法检测HSP70mRNA表达的变化。结果庆大霉素在作用HK-2细胞24、48、72h后,MTT吸光度值为0·166±0·02、0·181±0·009、0·237±0·016,均低于对照组0·187±0·011、0·32±0·016、0·515±0·035(P<0·01);HSP70蛋白阳性表达率(%)分别为69±17、86±21、89±25,均高于对照组6±3、4±3、7±2(P<0·01);还可增加HSP70蛋白和mRNA表达(P<0·01)。结论庆大霉素在降低人肾小管上皮细胞系细胞增殖活力的同时,增加HSP70的表达。     

苄基四氢巴马汀细胞内用药对豚鼠乳头状肌动作电位和 心室肌细胞延迟整流钾电流的作用

目的　研究将苄基四氢巴马汀 (BTHP)导入细胞内对豚鼠乳头状肌动作电位及单个心室肌细胞延迟整流钾电流的影响。方法　利用外加电压脉冲将药物导入乳头状肌细胞内 ,并用标准微电极方法测定动作电位 ;利用浓度差扩散方式使药物进入单个心室肌细胞内 ,采用全细胞膜片钳技术记录延迟整流钾电流 (IK)。结果　 10 0 μmol·L-1BTHP使APD2 0 和APD90 分别延长 13 5 %和 2 0 5 %。 30 μmol·L-1BTHP使IK 和IK ,tail分别从 (14 1± 2 2 )pA·pF-1和 (4 0± 0 6 ) pA·pF-1降至 (9 4± 1 3) pA·pF-1和 (2 1± 1 0 ) pA·pF-1,下降率分别为 33 2 %和 35 3%。该药使IK 和IK ,tail的I V曲线幅度降低 ,对曲线形状影响不明显。结论　BTHP入细胞内后可阻滞延迟整流钾电流和延长动作电位时程。     

Adrenergic nerves compensate for a decline in calcium buffering during ageing

1. The ubiquitous involvement of intracellular calcium ([Ca2+]i) in multiple neuronal pathways has led investigators to suggest that dysfunction of calcium homeostasis may be the primary mediator of age-related neuronal degeneration. Recently, it was shown that sympathetic neurones from superior cervical ganglion (SCG) of aged rats demonstrate decreased sarco-/endoplasmic reticulum Ca2+-ATPase (SERCA) function and that aged neurones are more dependent upon mitochondria to control K+-evoked [Ca2+]i transients. 2. Therefore, in the present study we investigated age-related changes in ATP-dependent calcium pumps of plasma membrane Ca2+-ATPase (PMCA) and SERCA in acutely dissociated SCG cells from Fischer-344 rats aged 6 and 20 months. To distinguish between PMCA and SERCA pump activity, we applied the Ca2+-ATPase blocker vanadate and measured rates of recovery of K+-evoked [Ca2+]i transients by fura-2 microfluorometry. 3. Young SCG cells showed a biphasic response to vanadate over the vanadate concentration range (0.01-100 microM); however, old SCG cells showed only a single response over the same concentration range. Additionally, old SCG cells showed a greater sensitivity to Ca2+-ATPase blockade by vanadate. 4. The contribution of mitochondrial calcium uptake to regulate [Ca2+]i was also investigated. To measure the impact of mitochondrial calcium uptake, PMCAs and SERCAs were blocked with vanadate (100 microM) and extracellular sodium was replaced with tetraethylammonium (TEA) to block Na+/Ca2+-exchange. Treated SCG cells showed a decline of 50% in rate of recovery of [Ca2+]i in both 6- and 20-month-old cells; however, this effect did not vary with age. 5. These data suggest that there is an age-related decline in function of SERCAs, with an increased reliance on PMCAs to control high K+-evoked [Ca2+]i transients. In addition, there appears to be no age-related change in the capacity of the mitochondria to restore [Ca2+]i transients to basal levels.     

Differential regulation of calcium homeostasis in adenocarcinoma cell line A549 and its Taxol-resistant subclone

Drug resistance is a fundamental problem in cancer chemotherapy. Intracellular calcium concentration ([Ca2+](i)) may play a role in the development of chemoresistance. We investigated the regulatory role of [Ca2+](i) in Taxol resistance in the non-small-cell lung cancer cell line A549 and its chemoresistant subclone A549-T24. Measurement of cytosolic calcium ([Ca2+](c)) in single cells and cell populations revealed similar levels of basal calcium in the two cell lines. However, a reduced response to thapsigargin (a sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitor) in A549-T24 cells compared to the parent cell line suggested a lower ER Ca2+ content in these cells. mRNA expression of SERCA2b and SERCA3, major Ca2+ pumps involved in ER Ca2+ homeostasis, did not significantly differ between the two cell lines, as revealed by RT-PCR. An altered calcium influx pathway in the Taxol-resistant cell line was observed. Modulation of the ER calcium pools using CMC (4-chloro-m-cresol) and ATP revealed lower ryanodine receptor (RyR) and IP(3) receptor (IP(3)R)-sensitive Ca2+ stores in the chemoresistant cell line. Western blot and RT-PCR studies suggested that A549-T24 cells expressed higher levels of the antiapoptotic protein Bcl-2 and the calcium-binding protein sorcin, respectively, in comparison to the parent cell line. Both of these proteins have been previously implicated in chemoresistance, in part, due to their ability to modulate[Ca2+](i). These results suggest that altered intracellular calcium homeostasis may contribute to the Taxol-resistant phenotype.     

SARCOPLASMIC RETICULUM IN VASCULAR CELLS IN HYPERTENSION AND DURING PROLIFERATION

1. Multiple sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) and two types of sarcoplasmic reticulum Ca2+ channels, the ryanodine receptor and the inositol 1,4,5 triphosphate (IP3) receptor are expressed. The heterogeneity of the Ca2+ pumps and Ca2+ channels in vascular cells will be discussed. 2. An age-related change in expression of the SERCA isoforms is observed in smooth muscle cells. 3. The sarcoplasmic reticulum Ca(2+)-uptake rate and the level of SERCA 2 mRNA are different in thoracic than in abdominal aortas and in aortas from spontaneously hypertensive rats than from normotensive rats. 4. Proliferation of vascular smooth muscle cells is associated with major changes in intracellular Ca(2+)-handling mechanisms.     

果糖二磷酸钠对大鼠心肌缺血的防治作用及其机制

目的　研究口服果糖二磷酸钠对异丙肾上腺素致大鼠心肌缺血时心肌细胞的凋亡及对心肌细胞肌浆网钙泵活性的影响。方法　在大鼠皮下注射异丙肾上腺素造成的心肌缺血坏死模型上 ,同时给予果糖二磷酸钠灌胃 ,观察心肌病理变化 ,以缺口末端标记法 (TUNEL)及免疫组化法检测心肌凋亡细胞、心肌细胞Fas、Bcl 2基因蛋白表达的变化 ,及应用 p 硝苯基磷酸法测定心肌细胞肌浆网钙泵活性变化 ,应用原子吸收法测定心肌钙含量。结果　应用异丙肾上腺素可导致明显的心肌缺血坏死及纤维化 ;缺血心肌组织中心肌细胞凋亡指数及Fas、Bcl 2基因蛋白表达量增加 (P <0 0 1) ,同时心肌细胞肌浆网钙泵活性降低 (P <0 0 5 )而心肌的钙含量却升高 (P <0 0 5 )。应用果糖二磷酸钠灌胃治疗能明显减轻心肌坏死及纤维化 (P <0 0 1) ,降低心肌组织细胞的凋亡 (P <0 0 5 )、心肌组织Fas基因的蛋白表达 (P <0 0 5 )及上调Bcl 2基因的蛋白的表达 (P <0 0 5 ) ;而且可以部分恢复心肌细胞肌浆网的钙泵活性 (P <0 0 5 ) ,降低心肌钙含量 (P <0 0 5 )。结论　口服果糖二磷酸钠可以保护由儿茶酚胺增多所引起的心肌缺血损伤 ,其机制与其能恢复心肌细胞肌浆网上的钙泵活性 ,调节心肌细胞的钙代谢紊乱 ,并抑制心肌缺血引起的细胞凋亡有关     

Sodium fluoride increases intracellular calcium in rat renal epithelial cell line NRK-52E

In our previous experiment using rats, fluoride was reported to cause renal calcification, whose mechanism was deduced to be due to an increase in parathyroid hormone (PTH) secretion. However fluoride-induced renal calcification that was independent of PTH has not been understood well in the nephron of fluoride-treated animals. Thus, we examined the effect of sodium fluoride on intracellular calcium mobilization in a normal rat kidney epithelial cell line (NRK-52E cells). The calcium accumulation was found to be remarkably increased by the addition of sodium fluoride (NaF). The elevation of [Ca2+]i was demonstrated to be due to calcium entry through nifedipine-sensitive calcium channels. In addition, fluoride activates phospholipase C, but inositol 1,4,5-triphosphate (IP3) didn't induce Ca2+ release from the endoplasmic reticulum (ER). Moreover, fluoride alone was deduced to enhance the activity of ER-type Ca2+-ATPase. Finally, on the mechanism of fluoride-induced calcium accumulation in NRK-52E cells, fluoride may activate phospholipase C to generate IP3 and diacylglycerol, and these increases can be elucidated to induce calcium entry through dihydropiridine-sensitive calcium channels. Moreover, fluoride was found to stimulate calcium accumulation through ER-type Ca2+-ATPase into the endoplasmic reticulum. The elevation of ER-type Ca2+-ATPase activity by fluoride was elucidated to operate as a regulatory system to protect against abnormally higher increases in cytosolic calcium concentration via an increase of calcium influx into the endoplasmic reticulum.     

17Beta-oestradiol regulates the expression of Na+/K+-ATPase beta1-subunit, sarcoplasmic reticulum Ca2+-ATPase and carbonic anhydrase iv in H9C2 cells

1. It is necessary to improve our understanding of the effect of 17beta-oestradiol (E2) on the heart at a molecular and cellular level. In the present study, the effects of E2 on Na(+)/K(+)-ATPase, sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) and carbonic anhydrase IV (CAIV) in H9C2 cells were investigated. To identify the mechanism of action of E2 on these proteins, the oestrogen receptor (ER) antagonist tamoxifen was used. 2. The results indicated that 1 and 100 nmol/L E2 can enhance the activity of Na(+)/K(+)-ATPase and SERCA and upregulate the expression of the Na(+)/K(+)-ATPase beta1-subunit, SERCA2a and CAIV at both the mRNA and protein level compared with 0 and 0.01 nmol/L E2. 17beta-Oestradiol had the greatest effect at 100 nmol/L; 1 micromol/L E2 did not further protein expression compared with 100 nmol/L E2. 3. Tamoxifen (10 nmol/L) significantly decreased the activity of SERCA, as well as the expression of the Na(+)/K(+)-ATPase beta1-subunit and SERCA at the mRNA and protein level, in H9C2 cells cultured with 1 nmol/L E2. Tamoxifen alone had no significant effect on these proteins in H9C2 cells. 4. It may be hypothesized that a suitable E2 concentration has a protective effect on the heart and that the actual dose of E2 used in hormone-replacement therapy is important in menopausal women.     

Effect of endothelin antagonism on contractility, intracellular calcium regulation and calcium regulatory protein expression in right ventricular hypertrophy of the rat

We have documented the effects of long-term endothelin receptor antagonism on intracellular Ca2+ regulation and Ca2+ regulatory protein expression in rat hearts with right ventricular hypertrophy without signs of heart failure. Rats were given either a single injection of monocrotaline (50 mg/kg, n=9) resulting in pulmonary hypertension-induced myocardial hypertrophy, or monocrotaline followed by daily administration of the endothelin subtype-A receptor antagonist 2-benzo(1,3)dioxol-5-yl-3-benzyl-4-(4-methoxy-phenyl-)-4-oxobut-2-enoate-Na (PD 155080, 50 mg/kg) over 9 weeks (n=8). Hearts from saline-injected rats served as controls (n=9). Monocrotaline-treated animals developed marked right-sided hypertrophy without fibrosis as evident from hydroxyproline measurements, systolic contractility was increased, fully compensating for the increased afterload, but diastolic function was impaired as evident from protracted relaxation and slowed diastolic intracellular Ca2+ handling (measured by aequorin bioluminescence). In hypertrophic hearts, quantitative immunoblotting analyses showed increased levels both of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and phosphorylated phospholamban, along with decreased levels of total phospholamban, which is in line with strengthened right ventricular systolic function. PD 155080 reversed abnormalities in Ca2+ handling, although SERCA and phospholamban protein levels were not altered (P=not significant versus monocrotaline group). Thus, endothelin-A receptor antagonism attenuates right ventricular remodeling and improves myocardial Ca2+ handling, but has no discernable effect on elevated expression of SERCA and phospholamban observed in hypertrophic hearts. These data indicate that the hypotensive action of PD 155080 is independent of its effects, if any, on SERCA and its regulation.     

细胞钙转运系统研究进展*

钙离子是重要的细胞信号分子。胞内和胞外、胞浆和细胞器之间的Ca2+转运都依赖于钙转运系统的精确调控。钙转运系统包括钙泵、钙通道、Na+/Ca2+交换体及膜结构域,如质膜的PMCA、NCX、VGCC、LGCC和TRP通道;内质网膜的SERCA、IP3Rs和RyRs等;线粒体的MCU和NCLX;内溶酶体的TPCs;联结质膜和内质网膜的CRAC通路;联结内质网膜和线粒体膜的MAM结构域等。本文对定位于质膜、内质网和线粒体的钙转运系统的种类、功能、组织分布、相关疾病以及抑制剂作综述。     

Modification of alterations in cardiac function and sarcoplasmic reticulum by astragaloside IV in myocardial injury in vivo

Astragaloside IV, the primary pure saponin isolated from Astragalus membranaceus has been found to have potent cardioprotective effects. In this study, we aim to investigate if the beneficial effects of astragaloside IV on cardiac function are associated with improvement in sarcoplasmic reticulum Ca(2+)-pump function in myocardial injury in vivo. Myocardial injury in rats was induced by subcutaneous injection of a high dose of isoproterenol, and the therapeutic effect of astragaloside IV was observed. Isoproterenol-treated rats showed widespread subendocardial necrosis, a rise in serum lactate dehydrogenase and creatine kinase, formation of lipid oxide product malondialdehyde and inhibition of left ventricular diastolic and systolic function, which suggested severe myocardial injury and acute heart failure. Moreover, sarcoplasmic reticulum Ca(2+)-uptake ability and Ca(2+)-ATPase (SERCA2a) activity were significantly reduced. And the level of SERCA2a mRNA and protein expression was also markedly decreased, associated with a decrease in Ser(16)-phosphorylated phospholamban protein expression, while total phospholamban level was unchanged in the isoproterenol-treated group compared with controls. However, these biochemical and hemodynamic changes in the acute failing hearts were prevented by treatment of isoproterenol-induced rats with astragaloside IV. Likewise, the observed reductions in sarcoplasmic reticulum Ca(2+)-pump function as well as in SERCA2a mRNA and protein levels and the phosphorylation level of phospholamban in the injured hearts were attenuated by astragaloside IV treatment. These results suggest that the beneficial effect of astragaloside IV on isoproterenol-induced myocardial injury may be due to its ability to prevent changes of SERCA2a and Ser(16)-phosphorylated phospholamban protein expression and, thus, may prevent the depression in sarcoplasmic reticulum Ca(2+) transport and improve cardiac function.