Effect of Chengzai Pill on the L-Type Ca^(2+) Channel Currents of Osteoblasts Pretreated with Methylprednisolone

Objective: To observe the effect of the serum containing Chengzai Pill on the L-type voltage-sensitive calcium channels current (L-VSCCsC) of osteoblastic MC3T3-E1 cells pretreated with methylprednisolone (mPSL). Methods: A control group, a model group, a low dose group and a high dose group were set up. The whole cell patch clamp technique was used to record L-VSCCsC of 10 osteoblastic MC3T3-E1 cells in each group and their peak currents were determined. Results: The peak current of the control group was 0.2284±0.0209 nA; the peak current of the model group was 0.1839±0.0179 nA; decreased by 19.5% as compared with the control group (P<0.01); the peak current of the low and high dose groups was 0.2526± 0.0093 nA and 0.2671±0.0120 nA respectively, increased by 37.4% and 45.2% as compared with the model group (P<0.01); the difference between the low and high dose groups was P<0.05. Conclusion: 1. mPSL inhibits L-VSCCsC of osteoblasts; and 2. The serum containing Chengzai Pill increases L-VSCCsC of osteoblasts pretreated with mPSL.

Effects of Tiaomaiyin and Its Disassembled Prescription on Expression of L-type Calcium Channel β2 Subunit in Rat Model of Tachyarrhythmia

[Objectives] To study the effects of Tiaomaiyin and its disassembled prescription on expression of L-type calcium channel β2 subunit in rat model of tachyarrhythmia. [Methods] Sixty Wistar rats were randomly divided into model group,Tiaomaiyin prescription group( whole prescription group),main efficacy group of removing heat to cool blood( blood cooling group),and auxiliary drug efficacy group of benefiting qi and nourishing heart( qi benefiting group),auxiliary efficacy group of promoting flow of qi and blood circulation( qi flow promoting group),and amiodarone group( western medicine group). Aconitine was given 7 d after the intragastric administration of the corresponding drugs,and the time of occurrence of arrhythmia in each group was observed. The left ventricular myocardium was subjected to reverse transcription-polymerase chain reaction and Western blotting. [Results] The ventricular premature beats( VPB) time in the whole prescription group and western medicine group was significantly longer than that in the model group. Ventricular tachycardia( VT),ventricular fibrillation( VF),and cardiac arrest( CA) were longer in the whole prescription group,blood cooling group,and western medicine group. The mRNA and protein expression of L-type calcium channel β2 subunit in the whole prescription group,blood cooling group and western medicine group were significantly decreased. [Conclusions] Tiaomaiyin whole prescription group and blood cooling group can reduce the occurrence time of tachyarrhythmia and reduce the expression of LTCC β2 in myocardium.

干姜吴茱萸水煎液对大鼠结肠平滑肌细胞L型Ca^(2+)通道的影响

目的:探讨干姜吴茱萸水煎液对大鼠结肠平滑肌收缩及平滑肌细胞L型Ca^(2+)通道的影响机制。方法:采用0、0.01、0.1、1、10 g/L干姜吴茱萸(1∶1)水煎液依次作用于正常结肠平滑肌,10 g/L水煎液及L型Ca^(2+)通道激动剂BAY-K-8644依次作用于氯化乙酰胆碱(Ach)诱导后的正常平滑肌,检测平滑肌收缩张力、频率和振幅;全细胞膜片钳记录L型钙电流;Western blot检测各组细胞中L-型电压依赖钙离子通道α1C亚基(α1c)和钙调蛋白(CaM)蛋白表达情况。结果:1、10 g/L水煎液组能显著降低离体结肠平滑肌的收缩张力(P<0.05),对频率及振幅并无显著影响(P>0.05);与0 g/L水煎液组相比,Ach促进平滑肌收缩张力、频率和振幅显著增加(P<0.05);与Ach组相比,10 g/L水煎液显著降低平滑肌的收缩张力、频率和振幅(P<0.05);与10 g/L水煎液组相比,BAY-K-8644显著增加平滑肌的收缩张力、频率和振幅(P<0.05);与0 g/L水煎液组相比,Ach可显著增加ICa-L峰值电流密度(P<0.05);与Ach组相比,10 g/L水煎液显著降低ICa-L峰值电流密度(P<0.05);与10 g/L水煎液组相比,BAY-K-8644可显著增加ICa-L峰值电流密度(P<0.05);与对照组相比,Ach组结肠平滑肌细胞Ca^(2+)相对荧光强度峰值、α1c、CaM表达显著增加(P<0.05);Ach组相比,10 g/L组Ca^(2+)相对荧光强度峰值、α1c和CaM表达水平显著降低(P<0.05);与10 g/L组相比,BAYK-8644组Ca^(2+)相对荧光强度峰值、α1c、CaM表达显著增加(P<0.05)。结论:干姜吴茱萸水煎液可抑制大鼠结肠平滑肌收缩,并阻滞L型Ca^(2+)通道。

低温缺血-再灌注对离体大鼠心房肌Kir2.1和CaMKⅡ表达的影响

目的探讨再灌注房性心律失常心房肌复极时程延长的分子机制。方法采用随机数字表法将16只由雄性SD大鼠制备的Langendorff离体心脏灌注模型分为对照组(C组,n=8)和低温缺血-再灌注组(IR组,n=8)。根据再灌注后是否发生房性心律失常,将IR组进一步细分为再灌注非房性心律失常亚组(N-RAA组)和再灌注房性心律失常亚组(R-AA组)。C组使用37℃K-H液平衡灌注120 min。IR组使用37℃K-H液平衡灌注30 min后停止,注射4℃Thomas液(20 mL/kg)使心脏停跳60 min,停跳30 min时使用半量4℃Thomas液(10 mL/kg)对离体心脏进行复灌[停跳期间用低温Thomas液(4℃)对心脏进行保护],后再次灌注37℃K-H液30 min。记录平衡灌注30 min(T_(0))、平衡灌注105 min/再灌注15 min(T_(1))和平衡灌注120 min/再灌注30 min(T_(2))时右心房单相动作电位(MAP),测量单相动作电位复极50%和90%的时程(MAPD_(50)和MAPD_(90))。电生理指标监测完后用Western blot检测右心房组织内向整流钾通道2.1(Kir2.1)和Ca^(2+)/CaM依赖激酶Ⅱ(CaMKⅡ)的表达。结果与T_(0)时点比较,R-AA组T_(1)、T_(2)时MAPD_(50)、MAPD_(90)明显延长(P<0.05);与C组比较,R-NAA组和R-AA组T_(1)、T_(2)时MAPD_(90)明显延长(P<0.05);与R-NAA组比较,R-AA组T_(1)、T_(2)时MAPD_(50)、MAPD_(90)明显延长(P<0.05)。Western blot结果显示,R-NAA组和R-AA组Kir2.1表达明显少于C组(P<0.05),且R-AA组明显少于R-NAA组(P<0.05);R-NAA组和R-AA组CaMKⅡ表达较C组明显增加(P<0.05),且R-AA组CaMKⅡ表达较R-NAA组明显增加(P<0.05)。结论低温缺血-再灌注房性心律失常大鼠心房肌复极时程延长可能与Kir2.1表达下调和CaMKⅡ表达增加有关。

MicroRNA-155 mediates endogenous angiotensin II type 1 receptor regulation:implications for innovative type 2 diabetes mellitus management

Type 2 diabetes mellitus(T2DM)is a lifelong condition and a threat to human health.Thorough understanding of its pathogenesis is acutely needed in order to devise innovative,preventative,and potentially curative pharmacological interventions.MicroRNAs(miRNA),are small,non-coding,one-stranded RNA molecules,that can target and silence around 60%of all human genes through translational repression.MiR-155 is an ancient,evolutionarily well-conserved miRNA,with distinct expression profiles and multifunctionality,and a target repertoire of over 241 genes involved in numerous physiological and pathological processes including hematopoietic lineage differentiation,immunity,inflammation,viral infections,cancer,cardiovascular conditions,and particularly diabetes mellitus.MiR-155 Levels are progressively reduced in aging,obesity,sarcopenia,and T2DM.Thus,the loss of coordinated repression of multiple miR-155 targets acting as negative regulators,such as C/EBPβ,HDAC4,and SOCS1 impacts insulin signaling,deteriorating glucose homeostasis,and causing insulin resistance(IR).Moreover,deranged regulation of the renin angiotensin aldosterone system(RAAS)through loss of Angiotensin II Type 1 receptor downregulation,and negated repression of ETS-1,results in unopposed detrimental Angiotensin II effects,further promoting IR.Finally,loss of BACH1 and SOCS1 repression abolishes cytoprotective,anti-oxidant,anti-apoptotic,and anti-inflam matory cellular pathways,and promotesβ-cell loss.In contrast to RAAS inhibitor treatments that further decrease already reduced miR-155 Levels,strategies to increase an ailing miR-155 production in T2DM,e.g.,the use of metformin,mineralocorticoid receptor blockers(spironolactone,eplerenone,finerenone),and verapamil,alone or in various combinations,represent current treatment options.In the future,direct tissue delivery of miRNA analogs is likely.

Relationship of Intracellular Free Ca^(2+) Concentration and Calcium-activated Chloride Channels of Pulmonary Artery Smooth Muscle Cells in Rats under Hypoxic Conditions

To investigate the relationship between intracellular free Ca~ 2+ concentration (Ca~ 2+_i) and calcium-activated chloride (Cl_ca ) channels of pulmonary artery smooth muscle cells (PASMCs) in rats under acute and chronic hypoxic conditions, acute hypoxia-induced contraction was observed in rat pulmonary artery by using routine blood vascular perfusion in vitro. The fluorescence Ca~ 2+ indicator Fura-2/AM was used to observe Ca~ 2+ _i of rat PASMCs under normal and chronic hypoxic condition. The effect of Cl_ ca channels on PASMCs proliferation was assessed by MTT assay. The Cl_ ca channel blockers niflumic acid (NFA) and indaryloxyacetic acid (IAA-94) exerted inhibitory effects on acute hypoxia-evoked contractions in the pulmonary artery. Under chronic hypoxic condition, Ca~ 2+ _i was increased. Under normoxic condition, Ca~ 2+ _i was (123.63±18.98) nmol/L, and in hypoxic condition, Ca~ 2+ _i was (281.75±16.48) nmol/L (P<0.01). Under normoxic condition, Ca~ 2+ _i showed no significant change and no effect on Cl_ ca channels was observed (P>0.05). Chronic hypoxia increased Ca~ 2+ _i which opened Cl_ ca channels. The NFA and IAA-94 blocked the channels and decreased Ca~ 2+ _i from (281.75±16.48) nmol/L to (117.66±15.36) nmol/L (P<0.01). MTT assay showed that under chronic hypoxic condition NFA and IAA-94 decreased the value of absorbency (A value) from 0.459±0.058 to 0.224±0.025 (P<0.01). Hypoxia increased Ca~ 2+ _i which opened Cl_ ca channels and had a positive-feedback in Ca~ 2+ _i. This may play an important role in hypoxic pulmonary hypertension. Under chronic hypoxic condition, Cl_ca channel may play a part in the regulation of proliferation of PASMCs.

Measuring Ca^(2+) influxes of TRPC1-dependent Ca^(2+) channels in HL-7702 cells with Non-invasive Micro-test Technique

AIM:To explore the possibility of using the Non-invasive Micro-test Technique(NMT)to investigate the role of Transient Receptor Potential Canonical 1(TRPC1) in regulating Ca 2+ influxes in HL-7702 cells,a normal human liver cell line.METHODS:Net Ca 2+ fluxes were measured with NMT, a technology that can obtain dynamic information of specific/selective ionic/molecular activities on material surfaces,non-invasively.The expression levels of TRPC1 were increased by liposomal transfection,whose effectiveness was evaluated by Western-blotting and single cell reverse transcription-polymerase chain reaction. RESULTS:Ca 2+ influxes could be elicited by adding 1 mmol/L CaCl2 to the test solution of HL-7702 cells.They were enhanced by addition of 20μmol/L noradrenalin and inhibited by 100μmol/L LaCl3(a non-selective Ca 2+ channel blocker);5μmol/L nifedipine did not induce any change.Overexpression of TRPC1 caused increased Ca 2+ influx.Five micromoles per liter nifedipine did not inhibit this elevation,whereas 100μmol/L LaCl3 did.CONCLUSION:In HL-7702 cells,there is a type of TRPC1-dependent Ca 2+ channel,which could be detected via NMT and inhibited by La3+.

Inhibitory actions of mibefradil on steroidogenesis in mouse Leydig cells： involvement of Ca^2＋ entry via the T-type Ca^2＋ channel

细胞内部的营地和 Ca2+ 在 Leydig 房间涉及 steroidogenic 活动的规定，它协调回答到 luteinizing 荷尔蒙(LH ) 和人的 chorionic gonadotropin (hCG ) 。然而， Ca2+ 入口的鉴定在 Leydig 房间 steroidogenesis 含有不是明确的。这研究的目的是识别影响 Leydig 房间 steroidogenesis 的 Ca2+ 隧道的类型。在在刚分裂的 Leydig 的 vitro steroidogenesis，老鼠的房间被 hCG 孵化导致。steroidogenesis 上的 mibefradil (通常认为的 T 类型 Ca2+ 隧道 blocker ) 的效果用反向的抄写(RT ) 被估计为 steroidogenic 的聚合酶链反应分析用放射性免疫测定的尖锐规章的蛋白质(星) mRNA 表示和睾丸激素生产。面对 1.0 mmol L ? 1 细胞外的 Ca2+ ，在 1 ～ 100 IU 的 hCG 显著地提高了两星 mRNA 水平和睾丸激素分泌物(P < 0.05 ) ，并且 hCG 的 stimulatory 效果被 mibefradil 显著地以一种剂量依赖者方式减少(P < 0.05 ) 。而且，当外部 Ca2+ 被省略时，睾丸激素生产的导致 hCG 的增加完全被移开，暗示那个 Ca2+ 条目为导致 hCG 的 steroidogenesis 被需要。而且，补丁夹钳研究揭示了在一个集中范围看见的 mibefradil 敏感的 Ca2+ 水流的存在将近 paralleled 那些禁止的 steroidogenesis。一起，我们的数据提供刺激 hCG 的 steroidogenesis 被在鼠标的 Leydig 房间由 T 类型 Ca2+ 隧道执行的 Ca2+ 入口部分地至少调停的证据。

Functional remodeling of Ca^(2+)-activated Cl^-channel in pacing induced canine failing heart

To determine whether Ca2+ activated Cl-current (ICl（Ca）) contributes to the functional remodeling of the failing heart. Methods Whole cell patch-clamp recording technique was employed to record the ICl（Ca） in cardiac myocytes enzymatically isolated from rapidly pacing induced canine failing hearts at room temperature and compared that of the normal hearts （Nor）.Results The current density of DIDS （200M） sensitive ICl（Ca） induced by intracellular Ca2+ release trigged by L-type Ca2+ current (ICa,L) was significantly decreased in heart failare （HF） cells compared to Nor cells.At membrane voltage of 20mV,the ICl（Ca） density was 3.02±0. 54 pA/pF in Nor （n=6） vs.1.31±0.25 pA/pF in HF （n=8） cells,（P【0.01）,while the averaged ICa,L density did not show difference between two groups.The time constant of current decay of ICl（Ca） was similar in both types of cells.On the other hand,in intra cellular Ca2+ clamped mode,where the [Ca2+]i was maintained at 100nmol/L,ICl（Ca） density be increased significantly in HF cells when the membrane voltage at +30mV or higher.Conclusions Our results suggest that ICl（Ca） density was decreased in pacing induced failing heart but the channel function be enhanced.Impaired Ca2+ handing in HF cells rather than reduced ICl（Ca） channel function itself may have caused this abnormality.The ICl（Ca） density reduction might contribute to the prolongation of action potential in failing heart.The ICl（Ca） channel function up-regulation is likely to cause cardiac arrhythmia by inducing a delayed after depolarization,when Ca2+ overload occurred in diastolic failing heart cells.

Caribbean maitotoxin elevates [Ca^(2+)]i and activates non-selective cation channels in HIT-T15 cells

AIM:To investigate the cytotoxic mechanism of caribbean maitotoxin(MTX-C) in mammalian cells.METHODS:We used whole-cell patch-clamp techniques and fluorescence calcium imaging to determine the cellular toxic mechanisms of MTX-C in insulin secreting HIT-T15 cells,which is a system where the effects of MTX have been observed.HIT-T15 cells stably express L-type calcium current,making it a suitable model for this study.Using the fluorescence calcium indicator Indo-1 AM,we found that there is a profound increase in HIT-T15 intracellular free calcium 3 min after application of 200 nmol/L MTX-C.RESULTS:About 3 min after perfusion of MTX-C,a gradual increase in free calcium concentration was observed.This elevation was sustained throughout the entire recording period.Application of MTX-C did not elicit the L-type calcium current,but large cationiccurrents appeared after applying MTX-C to the extracellular solution.The current-voltage relationship of the cation current is approximately linear within the voltage range from-60 to 50 mV,but flattened at voltages at-80 and-100 mV.These results indicate that MTX-C induces a non-voltage activated,inward current under normal physiological conditions,which by itself or through a secondary mechanism results in a large amount of cationic influx.The biophysical mechanism of MTX-C is different to its isoform,pacific maitotoxin(MTX-P),when the extracellular calcium is removed.CONCLUSION:We conclude that MTX-C causes the opening of non-selective,non-voltage-activated ion channels,which elevates level of intracellular calcium concentration and leads to cellular toxicities.

茶树OSCA基因家族的鉴定及表达分析

钙通透性阳离子通道蛋白(OSCA)在植物调节高渗胁迫中发挥着重要作用。为了解OSCA基因家族在茶树响应干旱胁迫中的作用,本研究基于茶树全基因组数据对OSCA基因家族进行鉴定,分析CsOSCAs基因和蛋白结构以及启动子顺式作用元件,并对CsOSCAs在茶树不同组织、不同抗旱性品种间和干旱胁迫下的表达模式进行分析。结果表明:茶树基因组包含12个OSCA基因家族成员,分别命名为CsOSCA1~CsOSCA12;CsOSCAs基因编码的氨基酸序列长度为667~831 bp,蛋白分子量在76630.55~93563.99 kDa之间,等电点在6.15~9.33之间,含有9~12个跨膜结构域,均含有特征保守结构域DUF221,根据系统进化关系可以分为4个亚族;10个CsOSCAs基因定位于茶树7条染色体上,2个CsOSCAs基因定位于未锚定染色体的contig上;CsOSCAs基因编码的蛋白二级结构含有32%~38%的跨膜结构和60%~68%的α-螺旋;CsOSCAs基因具有组织表达特异性,CsOSCA2、CsOSCA3、CsOSCA11、CsOSCA12基因在干旱敏感的品种CN98中的表达量显著高于其他2个耐旱品种,9个基因响应PEG胁迫,其中CsOSCA2、CsOSCA3、CSOSCA5、CsOSCA8、CsOSCA10和CsOSCA12受干旱胁迫强烈诱导;进一步分析启动子顺式作用元件显示,6个基因含有干旱诱导响应元件,11个基因含有脱落酸响应元件。由此推测茶树OSCA基因家族在茶树响应干旱胁迫中发挥着重要的作用,此研究为茶树OSCA基因功能分析与茶树抗逆性研究提供参考。

Effect of Calmodulin and Voltage-dependent Ca^(2+) Channel on the Proliferation of Heptoma Cells Induced by Epidermal Growth Factor

The effect of thyrosine kinase, calmodulin and voltage-dependent Ca 2+ channel on the proliferation of hepatoma cells induced by EGF was studied. Hepatoma cell line SMMC7721 was cultured in RPMI1640 serum-free medium. DNA synthesis rate of hepatoma cells was measured by 3H-TdR incorporation. 10 -9 mol/L EGF could significantly stimulate the proliferation of hepatoma cells (P<0.05), and this effect might be significantly inhibited by tyrosine kinase inhibitor (P<0.001). Calmodulin inhibitor W-7 had no effect on the basic phase of cultured hepatoma cells (P> 0.05), but it had very significantly inhibitory effect on the proliferation of hepatoma cells induced by EGF (P<0.001). Voltage-dependent Ca 2+ channel inhibitor Varapamil had no inhibition on the proliferation of hepatoma cells induced by EGF (P>0.05). It had no effect on the basic phase of cultured hepatoma cells (P>0.05). It is suggested that tyrosine kinase and Ca 2+-calmodulin-dependent pathway may play a critical role on the proliferation of heptoma cells induced by EGF, and voltage-dependent Ca 2+ channel is independent of the effect of EGF.

Effects of isoflurane and ethanol on large conductance Ca^(2+)-activated K^+ channels

Objective: To study the effect of isoflurane and ethanol on large conductance Ca 2+-activated K + channels(BK channels). Methods: The cRNA of mslo1 encoding BK channels was injected into Xenopus oocytes. Oocytes were incubated in ND96 (96 mmol/L NaCl, 2.0 mmol/L KCl, 1.8 mmol/L CaCl 2, 1.0 mmol/L MgCl 2, and 5.0 mmol/L HEPES, pH 7.4) at 4 ℃. Patch clamp recording (outside-out) were performed after 2-3 d. Isoflurane was administrated by the vaporizer driven by air, ethanol was applied by a closed, manual-controlled administration system. Different test potentials from 0 to 10 mV were given to observe changes of currents. Results: 0.7 mmol/L and 1.2 mmol/L of isoflurane could inhibit BK currents obviously at different command potentials, but 50 mmol/L, 100 mmol/L, or 200 mmol/L of ethanol had no any effect on BK currents. Conclusion: Clinical concentration of isoflurane can distinctly inhibit isolating BK currents.

Correlation of large conductance Ca2+ activated K+ channelα andβ subunit expression in uterine smooth muscle with the postpartum hemorrhage induced by uterine inertia

Objective:To study the correlation of large conductance Ca2+ activated K+ channel (BKCa)α andβ subunit expression in uterine smooth muscle with the postpartum hemorrhage induced by uterine inertia.Methods: The puerperae who underwent cesarean section and had postpartum hemorrhage induced by uterine inertia in Panzhihua Women and Children Health Hospital between March 2015 and May 2017 were selected as the hemorrhage group of the study, and the puerperae who underwent cesarean section and were without postpartum hemorrhage in Panzhihua Women and Children Health Hospital during the same period were selected as the control group. Proper amount of uterine muscle tissue was collected during the cesarean section to measure the expression of BKCaα andβ subunits and the levels of contraction-related proteins in uterine muscle as well as the contraction characteristic parameters of the uterine muscle.Results: The mRNA expression and protein expression of BKCaα andβ subunits in uterine muscle tissue of hemorrhage group were significantly higher than those of control group;the contraction amplitude, contraction frequency and contraction activity of uterine muscle tissue as well as the OTR, COX2, CX43 and HSP27 levels in uterine muscle tissue of hemorrhage group were significantly lower than those of control group;the BKCaα andβ subunit expression in uterine muscle tissue of hemorrhage group were negatively correlated with the contraction amplitude, contraction frequency and contraction activity as well as the OTR, COX2, CX43 and HSP27 levels.Conclusion: The high expression of BKCa in uterine smooth muscle can reduce the uterine muscle contractility and decrease the levels of contraction-related proteins, and it is closely related to the occurrence of postpartum hemorrhage induced by uterine inertia.

三七皂甙单体Rb_1对心肌细胞Ca^（2＋）内流作用的研究

应用Ｆｕｒａ－２荧光技术及放射配基结合实验探讨三七皂甙单体Ｒｂ１对心肌细胞胞外Ｃａ２＋内流的作用。０．０４ｍｍｏｌ·Ｌ－１Ｒｂ１可以抑制高钾引起的大鼠心肌细胞胞浆Ｃａ２＋浓度的升高，且呈浓度依赖性；可以完全阻断高钾基础上的异丙肾上腺素的作用。其作用与钙通道拮抗剂维拉帕米类似。Ｒｂ１对大鼠心肌细胞膜上β受体亲和力和受体数均无明显影响。结果提示：Ｒｂ１对心肌细胞电压依赖性钙通道开放引起的胞内钙升高有抑制作用；对β受体相关联的钙通道开放引起的胞浆Ｃａ２＋升高也有抑制作用。而不影响β受体本身。

心衰大鼠心肌SR Ca^(2+)泵活性和Ca^(2+)释放通道密度的变化及培哚普利干预的影响

目的 探讨ACEI干预慢性心衰对心肌肌浆网 (SR)Ca2 + 泵活性和Ca2 + 释放通道 (RyR2 )密度的影响及意义。方法 通过结扎大鼠左冠脉建立慢性心衰模型 ,以培哚普利进行干预 ,对照观察血流动力学、左室心肌SRCa2 + 泵活性、[3 H]-ryanodine与RyR2 最大结合量 (Bmax)、Kd 值。结果 与对照组 (C组 )相比 ,心衰组 (F组 )LVEDP显著升高 (P <0 0 1) ,+dp/dtmax、-dp/dtmax显著降低 (P <0 0 1) ,培哚普利组 (P组 )LVEDP显著低于F组 (P <0 0 1) ,+dp/dtmax、-dp/dtmax显著高于F组 (P <0 0 1)。F组心肌SRCa2 + 泵活性、[3 H]-ryanodine与RyR2 最大结合量Bmax显著低于C组 (P <0 0 1) ,也显著低于P组 (P <0 0 1) ,三组Kd 值无显著差异 (P >0 0 5 )。心肌SRCa2 + 泵活性与 +dp/dtmax、-dp/dtmax显著正相关 (r=0 5 16 1、0 6 172 ,P <0 0 1)。结论 培哚普利长期干预慢性心衰 ,能够改善心肌SRCa2 + 泵活性 ,增加RyR2 密度 ,可能与其改善心肌舒缩功能及心肌保护作用有关。

萘甲异喹对大鼠心肌细胞Ca^(2+)内流的影响

目的研究萘甲异喹（NI）对大鼠心肌细胞外Ca(2+)内流的影响。方法：应用钙离子荧光指示剂Fura－2检测。结果：NI（3，10μmol·L(-1)）和维拉帕米（0．3μmol·L(－1)）对静息状态下心肌细胞内Ca(2+)浓度无影响，但可浓度依赖地抑制高钾（60mmol·L(-1)）和异丙肾上腺素（lμmol·L(－1)）引起的心肌细胞内Ca(2+)浓度的升高，抑制率分别为29％±6％、49％±9％和26％±6％、40％±8％；NI对两种激动剂作用的抑制百分率无明显差异，而维拉帕米对高钾作用的抑制大于对异丙肾上腺素作用的抑制。结论：NI对心肌细胞电压依赖性钙通道以及和β受体有关的钙通道有阻断作用，NI可能是非选择性钙通道阻滞剂。

巯亚硝基卡托普利对环匹阿尼酸引起的平滑肌细胞胞浆游离Ca^(2+)浓度升高作用的影响

目的 探讨巯亚硝基卡托普利 (S nitrosocaptopril,CapNO)对Ca2 + 池操纵性Ca2 + 内流信号转导过程的影响。方法 以Fura 2荧光探针测定胞浆游离Ca2 + 浓度([Ca2 + ]i)。结果 ①CapNO(2 0～ 12 0 μmol·L-1)呈浓度依赖性抑制环匹阿尼酸 (cyclopiazonicacid ,CPA)引起的[Ca2 + ]i 升高 ,80 μmol·L-1CapNO为最大效应浓度。相同浓度的captopril对CPA升高 [Ca2 + ]i 无明显抑制作用。②在 80 μmol·L-1CapNO抑制CPA引起 [Ca2 + ]i 升高作用的基础上 (31%± 11% ) ;随后加入 1μmol·L-1硝苯地平不能降低 [Ca2 + ]i,再加入 2 0 μmol·L-1SK&F96 36 5 (最大效应浓度 )可进一步降低 [Ca2 + ]i(5 4%± 18% ) ,其中SK&F96 36 5净抑制率为 2 4%± 10 % ,与SK&F96 36 5单独作用抑制率(5 4%± 11% )比较差异有显著性。③不同顺序给予最大效应浓度CapNO (80 μmol·L-1)和tyrphostinAG490 (2 μmol·L-1)对CPA引起 [Ca2 + ]i 升高存在交叉抑制作用。结论 CapNO可通过阻断电压依赖性Ca2 + 通道和Ca2 + 池操纵性Ca2 + 通道抑制CPA引起的 [Ca2 + ]i 升高 ,CapNO对CPA引起 [Ca2 + ]i 升高的阻断作用存在酪氨酸激酶 (Janus2亚型 )

库容性Ca^(2+)内流参与ACh诱导的大鼠远端结肠平滑肌收缩

应用生物换能技术和Ca2+通道特异性阻断剂观察并记录大鼠离体远端结肠平滑肌收缩张力的变化,分析库容性 Ca2+内流(capacitative Ca2+ entry,CCE)是否与ACh诱导的离体远端结肠平滑肌收缩反应有关。结果表明,以无钙的Krebs 液灌流或应用EGTA螯合细胞外Ca2+后,高K+及ACh引起的远端结肠平滑肌收缩几乎完全消失。电压操纵性Ca2+通道阻断剂veiapamil也能减弱高K+及ACh引起的远端结肠平滑肌收缩,其减弱的程度分别为74％和41％。在无钙的Krebs液中, 5 μmol／L ACh可引起离体肠管瞬时性收缩,这是由肌质网(sarcoplasmic reticulum,SR)释放钙所致;然后加入10 μmol／L阿托品(atropine),并在此基础上恢复细胞外Ca2+(2．5 mmol／L),结肠平滑肌则出现持续性收缩,待收缩反应达峰值时,加入5μmol／L verapamil,收缩无明显变化,且该收缩反应对钙库操纵性通道(store-operated Ca2+ channel,SOCC)阻断剂La3+ 敏感,20,50和100 μmol／L的La3+使上述收缩张力分别降低15％,23％和36％,且呈浓度依赖性,但对Cd2+不敏感。研究结果提示,细胞外Ca2+内流对高K+及ACh介导的离体远端结肠平滑肌持续性收缩是必需的,由ACh诱导的远端结肠平滑肌收缩至少包括SR释放钙引起的短暂性收缩及受体操纵性Ca2+通道(receptor-operated Ca2+ channel,ROCC)、电压操纵性Ca2+通道(voltage-operated Ca2+ channel,VOCC)和CCE介导的胞外Ca2+内流等途径。这将从通道水平进一步分析消化管平滑肌收缩的机制和特征,亦将为预防和控制因胃肠动力紊乱所致的消化管疾病寻求有针对性的药物干预和治疗提供理论依据。

高压氧对脑缺血及再灌注时海马游离Ca^（2＋）及钙通道的作用

应用新型钙离子荧光指示剂Ｆｕｒａ－２／ＡＭ测定海马突触体内游离Ｃａ￣（２＋）浓度，观察在脑缺血时及不同压力高压氧治疗后的变化规律，并应用［￣３Ｈ］ＰＮ２００－１１０作为放射性配基，用放射配体结合法测定海马组织Ｌ－型钙通道生物学特性和缺血及高压氧治疗后的变化。结果表明：脑缺血及再灌注后海马脑区突触体内游离Ｃａ￣（２＋）浓度显著增加，其Ｌ－型钙通道的Ｂｍａｘ和Ｋｄ值均显著上升，但经吸入高压氧后，可降低胞浆内游离Ｃａ￣（２＋）浓度，其中以２５３．２５ｋＰａ高压氧作用明显，并可降低钙通道的Ｂｍａｘ与Ｋｄ值。说明高压氧部分地通过减少细胞内游离Ｃａ￣（２＋）而起作用，Ｌ－型钙通道参与了高压氧降低脑缺血后胞浆内游离Ｃａ￣（２＋）浓度的作用，高压氧可使其开放的通道数量减少。