气管插管给氧与面罩给氧治疗大鼠羊水栓塞的对比研究

目的:探讨早期气管插管治疗羊水栓塞大鼠急性呼吸衰竭的价值。方法:前瞻性随机对照设计。取晚期妊娠（孕19²0d）Wistar雌鼠30只,剖宫取胎鼠、羊水后,按干预措施随机将Wistar雌鼠分为3组:A组10只经股静脉注入生理盐水后行面罩给氧,为空白对照组;其余20只经股静脉注入自体羊水加胎粪制作羊水栓塞模型后分别给予面罩给氧（B组）、气管插管给氧（C组）,每组10只。分别记录各组注射前、注射后5、15、30min的血气分析值。SPSS 11.0统计软件对血气分析数据运用重复测量资料的方差分析,LSD法进行3组间相同时间点测量值均数的两两比较分析。结果:注射前:血气分析值（PO₂,PCO₂,PH值）在3组之间差异无统计学意义。注射后:B组、C组PO₂数值先是迅速下降、之后有所回升,但均明显低于A组PO₂数值（P<0.01）,但此过程中C组PO₂数值均优于B组（P<0.01）;PCO₂和PH值在三组间则无统计学意义差异（P>0.05）。结论:与面罩给氧相比,大鼠羊水栓塞后采取气管插管给氧能更有效地改善血氧含量。     

大量输血后患者血清电解质、凝血功能及酸碱平衡变化情况分析

目的 探究大量输血后患者血清电解质、凝血功能及酸碱平衡变化情况。方法 选择2018年12月～2021年1月在院接受大量输血治疗的168例患者作为研究对象,对比分析输血前后电解质(Na⁺、K⁺、Ca²⁺、Cl^-)、凝血功能(PT、APTT、TT、FIB、PLT)、血气分析(pH值、Lac、BE)、TCO₂、肝功能(AST、ALT、TBil)、肾功能(BUN、Cr、UA)变化情况。结果 输血后K⁺、Ca²⁺、FIB、PLT、pH值、静脉血TCO₂水平低于输血前,PT、APTT、TT、BE、Lac、ALT、AST、TBil高于输血前,差异均有统计学意义(P<0.05);所有患者输血前后Na⁺、Cl^-、BUN、Cr、UA比较,差异无统计学意义(P>0.05)。结论 大量输血后会对机体电解质水平、凝血功能、酸碱指标产生一定影响,因此对输血患者,应密切监测电解质...     

枸橼酸钠抗凝的连续性血液净化中管路采血与外周血管采血的对比研究

目的 对比枸橼酸钠抗凝的连续性血液净化(CBP)中管路采血与外周血管采血进行血气分析的差异。 方法 选取2019 年 1 月至 2021 年 2 月本院进行枸橼酸钠抗凝的 CBP 治疗的 86 例患者进行研究。 采用自身对照法,同时经患者血液净化过滤器前管路和外周血管采集血液标本进行血气分析,根据采血方式的不同,将血液标本分为滤器前管路采血组和外周血管采血组, 比较两组血液标本的血气分析结果的差异。 结果 滤器前管路采血组和外周血管采血组的血液标本在钙离子(Ca²⁺)、钾离子(K⁺)、钠离子(Na⁺)、氯离子(CI^-)含量检测方面比较差异无统计学意义(P>0.05);滤器前管路采血组和外周血管采血组的血液标本在碳酸氢根离子(HCO₃^-)、二氧化碳分压(PCO₂)、氢离子浓度(pH)、碱过剩(BE)检测方面比较差异无统计学意义(P>0.05)。 结论 患者在进行枸橼酸钠抗凝的 CBP 治疗时 , 滤器前管路采血可以代替外周血...     

血清25-羟基维生素D钙离子水平对子痫前期发生及发展程度的预测价值

目的 检测血清25-羟基维生素D(25-OH-V_D)、钙离子(Ca⁺)水平子痫前期(PE)发生及发展程度的预测价值。方法 回顾性分析选择焦作市妇幼保健院2019年8月到2021年5月就诊的128例PE患者作为研究对象,并纳入观察组(128例),另外选取同期健康体检的100名健康妊娠产妇作为对照组。观察组根据病情严重程度分为轻度组(68例)和重度组(60例)。研究对象均进行25-OH-V_D、Ca²⁺指标检测,对比健康妊娠产妇及PE产妇、轻度及重度PE产妇的25-OH-V_D、Ca²⁺指标采用Logistic多因素分析PE发生的独立危险因素,采用Pearson相关性分析25-OH-V_D、Ca⁺指标与PE严重程度的相关性。结果 PE产妇25-OHV_D、Ca²⁺指标水平均明显低于健康妊娠产妇;重度PE产妇25-OH-V_D、Ca²⁺指标水...     

灯盏乙素介入IP3R-Ca2+途径抑制β淀粉样蛋白诱导的神经细胞凋亡

目的：观察灯盏乙素（Scu）对β淀粉样蛋白（Aβ）诱导的细胞模型中1，4，5-三磷酸肌醇受体（IP₃R）-Ca²⁺途径的影响，探讨其在阿尔茨海默病（AD）病程中可能发挥的积极作用。方法：选用神经母细胞瘤细胞分为对照组、Scu处理组、Aβ处理组、Aβ+Scu （高、中、低）处理组及Aβ+IP₃R拮抗剂组，用CCK-8法筛选药物浓度并检测各组细胞生存率；用酶联免疫吸附法检测各组细胞中1，4，5-三磷酸肌醇（IP₃）的含量；用蛋白印迹和实时荧光定量聚合酶链反应方法检测各组细胞IP₃R和凋亡相关因子Caspase-3、Bcl-2、Bax的蛋白及mRNA的表达水平；用激光共聚焦显微镜观察各组细胞内Ca²⁺浓度的变化；用AnnexinV/PI双染法测定各组细胞的凋亡率。结果：与对照组和Scu处理组相比，Aβ处理组细胞存活率下降，IP₃含量升高，IP₃R、Bax和Caspase-3的蛋白及mRNA表达上调，Bcl-2蛋白及mRNA的表达下调，细胞胞浆内Ca²⁺浓度及细胞凋亡率升高；Aβ+Scu处理组细胞中各检测指标的变化与Aβ处理组的结果正好相反，IP₃R通道下游指标的变化与Aβ+IP₃R拮抗剂组基本一致。结论：Scu能够下调通路蛋白IP₃、IP₃R的表达，抑制Aβ介导的Ca²⁺内流所致的细胞凋亡，可能通过对IP₃R-Ca²⁺途径的调控来影响AD病程。     

低压低氧环境对失血性休克动物氧合状态的影响

目的 探讨低压低氧环境对失血性休克大鼠氧合状态的影响。方法 将30只清洁大鼠随机分为失血性休克未进低压低氧舱组(A组)、未休克进低压低氧舱组(B组)、失血性休克进低压低氧舱组(C组),各10只。采用容控法制备失血性休克模型,分析各组不同时间点酸碱度(p H)、氧分压(PO₂)、二氧化碳分压(PCO₂)、血氧饱和度(Sa O₂)、乳酸(LAC)、碳酸氢根离子(^-HCO₃)、碱剩余(BE)、血糖(Glu)、血红蛋白(Hb)水平变化情况。结果A、C组T1时p H值及SaO₂、LAC、HCO₃^-、BE水平比较,差异有统计学意义(P<0.05),而PO₂、PCO₂、Glu、Hb水平比较,差异无统计学意义(P>0.05)。A、C组T3时p H值及HCO₃^-、BE水平比较,差异有统计学意义(P<0.05),而PO_...     

Ca2+/calpain信号调控纤连蛋白诱导的MCF-10A乳腺上皮细胞-间质转化的作用

目的：观察Ca²⁺/calpain信号通路在纤连蛋白（FN）诱导MCF-10A乳腺上皮细胞-间质转化（EMT）中的作用。方法：以正常培养MCF-10A乳腺上皮细胞为实验对象。采用比色法检测细胞内Ca²⁺浓度;采用荧光分光光度法检测钙蛋白酶-2（calpain-2）活性;Western blot法检测calpain-2、波形蛋白（vimentin）、E-钙黏着蛋白（E-cadherin）的表达;采用划痕修复实验检测细胞迁移能力;Transwell小室实验检测细胞侵袭能力。结果：FN诱导MCF-10A细胞中Ca²⁺浓度、calpain-2活性表达明显升高,上调vimentin、calpain-2蛋白表达,下调E-cadherin蛋白水平;FN诱导MCF-10A细胞迁移和侵袭能力显著增强。钙离子螯合剂（BAPTA-AM）和氨氯地平（amlodipine）均能显著抑制FN诱导的细胞Ca²⁺浓度、calpain-2活性及表达升高;抑制vimentin蛋白表达上调及E-cadherin蛋白表达下调;抑制FN诱导MCF-10A细胞迁移和侵袭能力增强。结论：BAPTA-AM和Amlodipine均能够抑制FN诱导的上皮间质转化。FN能够诱导MCF-10A乳腺上皮细胞发生EMT,可能与Ca²⁺/calpain信号通路激活有关。     

AVLcompactⅢ型血气分析仪评价

目的 :评价AVLcompactⅢ型血气分析仪的基本性能。方法 :从仪器的精密度 ,准确度 ,携带污染率来评价仪器 ,并将其与ABL330型血气分析仪作临床标本比较试验。结果 :AVLcompactⅢ血气分析仪测定PH、PCO2 和PO2 的精密度高 ,批间变异系数分别为0 21、3 16、6 17;准确性好 ,PH、PCO2 和PO2 的靶值分别为7 130、9 50、8 10 ,测定值分别为7 141、9 67、8 25 ;与ABL330型血气分析仪平行测定30份临床动脉血标本 ,结果高度一致 ,经配对资料t检验 ,t值均小于0 05 ,P>0 05 ,差异无显著性。结论 :该仪器性能稳定 ,精密度高 ,准确性好 ,适应于临床血气分析标本的测定     

通腑消积汤治疗呼吸衰竭患者腑气不通证的临床研究

目的 探析呼吸衰竭患者腑气不通证应用通腑消积汤治疗的临床效果。方法 80例呼吸衰竭腑气不通证患者,随机分为观察组与对照组,各40例。对照组采用乳果糖口服溶液治疗,观察组采用通腑消积汤治疗。对比两组治疗前后血气指标[动脉血酸碱度(pH)、血二氧化碳分压(PCO₂)、血氧分压(PO₂)]、中医证候积分改善情况及治疗效果。结果 观察组治疗总有效率92.50%高于对照组的72.50%,差异有统计学意义(P<0.05)。治疗后,观察组中医证候积分(4.38±1.02)分低于对照组的(6.89±1.07)分,差异有统计学意义(P<0.05)。治疗后,观察组PCO₂(32.17±5.16)mm Hg(1 mm Hg=0.133 kPa)低于对照组的(36.78±6.43)mm Hg,PO₂(89.45±10.36)mm Hg高于对照组的(82.48±10.13)mm Hg,差异有统计学意义(P<0.05)。结论 通腑消积汤应用于呼吸衰竭患者腑气不通证中的临床效果显著,可以有效改善临床相关症状,促...     

慢性阻塞性肺疾病急性加重期合并Ⅱ型呼吸衰竭患者应用无创正压通气治疗失败的影响因素分析

目的分析慢性阻塞性肺疾病急性加重期(AECOPD)合并Ⅱ型呼吸衰竭患者应用无创正压通气(NIPPV)治疗失败的影响因素。方法选取南平市建阳第一医院2017—2019年收治的AECOPD合并Ⅱ型呼吸衰竭患者84例,均采用NIPPV治疗。观察患者治疗效果,比较治疗前及治疗后2h、24h动脉血气指标[pH值、动脉血氧分压(PaO₂)、动脉血二氧化碳分压(PaCO₂)]及血氧饱和度(SaO₂)。根据治疗效果将患者分为NIPPV成功组和NIPPV失败组,收集2组患者一般资料、生命体征、动脉血气指标、血清生化指标及免疫指标等可能影响NIPPV的因素,包括性别(男、女)、年龄、COPD病史、急性生理学和慢性健康状况评分系统Ⅱ评分(APACHEⅡ)、日常生活能力评分(ADL评分)、通气前血气指标(pH值、PaO₂、PaCO₂、SaO₂)、呼吸频率(RR)、心率(HR)、收缩压(SBP)、合并疾病(糖尿病、心血管疾病、脑血管疾病)、空腹血糖、白蛋白、血红蛋白、白细胞、肌酐、尿素氮、C反应蛋白、T淋巴细胞亚群(CD₃⁺细胞分数、CD₄⁺细胞分数、CD₈⁺细胞分数),采用多因素Logistic回归分析上述因素对NIPPV通气失败的影响。结果 84例AECOPD合并Ⅱ型呼吸衰竭患者NIPPV成功60例(71.43%),NIPPV失败24例(28.57%),其中15例转为气管插管,插管率为17.86%,死亡7例,病死率为8.33%。NIPPV治疗24 h后pH值、PaO₂、SaO₂高于治疗前,PaCO₂低于治疗前(P<0.05)。NIPPV成功组和NIPPV失败组年龄、COPD病史、APACHEⅡ评分、ADL评分、pH值、PaO₂、PaCO₂、SaO₂、SBP、空腹血糖、WBC、CD₃⁺细胞分数、CD₄⁺细胞分数、CD₈⁺细胞分数比较,差异有统计学意义(P<0.05)。多因素Logistic回归分析结果显示,APACHEⅡ评分、pH值、PaO₂、PaCO₂、CD₃⁺细胞分数、CD₄⁺细胞分数、CD₈⁺细胞分数是导致NIPPV失败的独立危险因素(P<0.05)。结论NIPPV治疗AECOPD合并Ⅱ型呼吸衰竭疗效确切,能有效改善血气指标,但仍然约有28.57%患者可能出现NIPPV失败,主要与通气前APACHEⅡ评分、血气指标及T细胞亚群等指标有关。     

Homologous and heterologous desensitisation of somatostatin-induced increases in intracellular Ca and inositol 1,4,5-trisphosphate in CHO-K1 cells expressing human recombinant somatostatin sst5 receptors

The mechanisms responsible for somatostatin (SRIF)-induced increases in intracellular Ca²⁺ concentration ([Ca²⁺]_i) and subsequent desensitisation were studied in CHO-K1 cells expressing human sst₅ receptors (CHOsst₅ cells). To study the nature of the desensitisation, interactions with uridine triphosphate (UTP) were examined. SRIF (pEC₅₀ 7.10) and UTP (pEC₅₀ 5.14) caused concentration-dependent increases in [Ca²⁺]_i but the SRIF maximum was about 40% of that to UTP. SRIF-, but not UTP-, induced increases in [Ca²⁺]_i were transient and abolished by pertussis toxin. SRIF and UTP caused sustained increases in Ins(1,4,5)P₃ but the SRIF maximum was about 30% of that to UTP. Removal of [Ca²⁺ ]_e attenuated the SRIF-induced peak rise in [Ca²⁺]_i but had no effect on the peak increases in Ins(1,4,5)P₃. UTP-induced increases in [Ca²⁺]_i and Ins(1,4,5)P₃ were attenuated in the absence of [Ca²⁺]_e. Following pre-exposure to SRIF (1 μM) or UTP (100 μM) for 5 min, subsequent SRIF responses were desensitised. Similar results were obtained in the absence of [Ca²⁺]_e. Pre-exposure to SRIF had no effect on subsequent responses to UTP but in the absence of [Ca²⁺]_e, responses to UTP were attenuated. The results suggest that SRIF but not UTP-induced increases in [Ca²⁺]_i in CHOsst₅ cells are mediated by pertussis toxin sensitive G proteins and are caused by an entry of extracellular Ca²⁺ and release from an Ins(1,4,5)P₃ sensitive Ca²⁺ store. Homologous or heterologous desensitisation of agonist-induced increases in [Ca²⁺]_i could be demonstrated in the presence or absence of extracellular Ca²⁺ respectively, and the latter appeared to involve depletion of a common intracellular Ca²⁺ store.     

CGP37157 modulates mitochondrial Ca homeostasis in cultured rat dorsal root ganglion neurons

The effects of 7-chloro-3,5-dihydro-5-phenyl-1H-4,1-benzothiazepine-2-on (CGP37157), an inhibitor of mitochondrial Na⁺/Ca²⁺ exchange, on depolarization-induced intracellular free Ca²⁺ concentration ([Ca²⁺]_i) transients were studied in cultured rat dorsal root ganglion neurons with indo-1-based microfluorimetry. A characteristic plateau in the recovery phase of the [Ca²⁺]_i transient resulted from mitochondrion-mediated [Ca²⁺]_i buffering. It was blocked by metabolic poisons and was not dependent on extracellular Ca²⁺. CGP37157 produced a concentration-dependent decrease in the amplitude of the mitochondrion-mediated plateau phase (IC₅₀=4±1 μM). This decrease in [Ca²⁺]_i was followed by an increase in [Ca²⁺]_i upon removal of the drug, suggesting that Ca²⁺ trapped in the matrix was released when the CGP37157 was removed from the bath. CGP37157 also inhibited depolarization-induced Ca²⁺ influx at the concentrations required to see effects on [Ca²⁺]_i buffering. Thus, CGP37157 inhibits mitochondrial Na⁺/Ca²⁺ exchange and directly inhibits voltage-gated Ca²⁺ channels, suggesting caution in its use to study [Ca²⁺]_i regulation in intact cells.     

Lignans from Kadsura angustifolia

A new dibenzocyclooctadiene lignan named angustifolin D (1) together with four known lignans: kadsulignan L (2), kadsulignan N (3), schisantherin P (4) and meso-dihydroguaiaretic acid (5) were isolated from the stems of Kadsura angustifolia. Their structures and stereochemistries were elucidated by spectral studies. Compounds 2 and 5 showed moderate plateletactivating factor (PAF) antagonistic activities with IC₅₀ values of 2.6 × 10^-5 and 4.1 × 10^-5 M, respectively.     

Sarcoplasmic reticulum Ca2+ release channel ryanodine receptor (RyR2) plays a crucial role in aconitine-induced arrhythmias

The present study established a model of RyR₂ knockdown cardiomyocytes and elucidated the role of RyR₂ in aconitine-induced arrhythmia. Cardiomyocytes were obtained from hearts of neonatal Sprague–Dawlay rats. siRNAs were used to down-regulate RyR₂ expression. Reduction of RyR₂ expression was documented by RT-PCR, western blot, and immunofluorescence. Ca²⁺ signals were investigated by measuring the relative intracellular Ca²⁺ concentration, spontaneous Ca²⁺ oscillations, caffeine-induced Ca²⁺ release, and L-type Ca²⁺ currents. In normal cardiomyocytes, steady and periodic spontaneous Ca²⁺ oscillations were observed, and the baseline [Ca²⁺]_i remained at the low level. Exposure to 3 μM aconitine increased the frequency and decreased the amplitude of Ca²⁺ oscillations; the baseline [Ca²⁺]_i and the level of caffeine-induced Ca²⁺ release were increased but the L-type Ca²⁺ currents were inhibited after application of 3 μM aconitine for 5 min. In RyR₂ knockdown cardiomyocytes, the steady and periodic spontaneous Ca²⁺ oscillations almost disappeared, but were re-induced by aconitine without affecting the baseline [Ca²⁺]_i level; the level of caffeine-induced Ca²⁺ release was increased but L-type Ca²⁺ currents were inhibited. Alterations of RyR₂ are important consequences of aconitine-stimulation and activation of RyR₂ appear to have a direct relationship with aconitine-induced arrhythmias. The present study demonstrates a potential method for preventing aconitine-induced arrhythmias by inhibiting Ca²⁺ leakage through the sarcoplasmic reticulum RyR₂ channel.     

The effects of N-(5-vinyl-1,3-thiazolidin-2-ylidene)phenylamine (5-VTPA) on the changes in free intracellular calcium and the production of reactive oxygen metabolites in human leukocytes

Human leukocytes were exposed to N-(5-vinyl-1,3-thiazolidin-2-ylidene)phenylamine (5-VTPA), a postulated impurity in the case oils that caused the Spanish Toxic Oil Syndrome in 1981. Changes induced by 5-VTPA alone and together with a chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (FMLP), a tumor promoter, phorbol myristate acetate (PMA), or a synthetic diacylglycerol, dioctanoyl-s,n-glycerol (DiC₈) in free intracellular calcium levels ([Ca²⁺]_i) and in the induction of oxidative burst were measured. 5-VTPA elevated dose-dependently [Ca²⁺]_i and induced the production of reactive oxygen metabolites in leukocytes. 5-VTPA also amplified FMLP-induced increase in [Ca²⁺]_i, but was without an effect on FMLP-induced oxidative burst. On the contrary, 5-VTPA amplified dose-dependently PMA- and DiC₈-induced respiratory burst. The present results indicate that 5-VTPA may interfere with transmembrane signalling in human leukocytes. 5-VTPA may elevate [Ca²⁺]_i by acting directly on the membrane, or by acting through Ca²⁺-mobilizing receptors. Moreover, 5-VTPA also clearly amplified responses produced through protein kinase C stimulation. Thus, 5-VTPA may act on human leukocytes by affecting Ca²⁺-metabolism and the activity of protein kinase C.     

Ca dependence of the response of three adenosine type receptors in rat hepatocytes

The effect of three different receptor-specific adenosine agonists on the rate of ureagenesis by isolated rat hepatocytes and the dependence on the external free Ca²⁺ concentration ([Ca²⁺]_e) were investigated. In the presence of high [Ca²⁺]_e all adenosine receptor agonists increased ureagenesis to similar levels. However, with low [Ca²⁺]_e the effects of each agonist varied as follows: (i) the adenosine A₁ receptor agonist, 2-chloro-N⁶-cyclopentyl-adenosine, increased ureagenesis depending partially on [Ca²⁺]_e, (ii) the adenosine receptor A₂ agonist, 2-p-(-2-carboxy-ethyl) phenethylamino-5′-N-ethylcarboxyamido adenosine hydrochloride, increased ureagenesis independently of [Ca²⁺]_e and (iii) in contrast, the adenosine receptor A₃ agonist N⁶-2-(-4-aminophenyl) ethyladenosine, increased ureagenesis only in the presence of high [Ca²⁺]_e. The adenosine receptor A₁ antagonist, 1-allyl-3,7-dimethyl-8-phenyl xanthine, inhibited the effect of the adenosine receptor A₁ agonist on ureagenesis, but not the effect of the adenosine A₂ or A₃ receptor agonists. The adenosine A₂ receptor antagonist, 3,7-dimethyl-1-propargylxanthine, inhibited only the effect of the adenosine A₂ receptor agonist. Thus, in addition to A₁ and A₂ type adenosine receptors, rat hepatocytes possess an A₃-like adenosine receptor which responds to the addition of an adenosine A₃ agonist by accelerating ureagenesis a [Ca²⁺]_e dependent manner. Moreover, it was observed that in the presence of extracellular Ca²⁺ each agonist increased [Ca²⁺]_i and this effect was inhibited by the appropriate specific antagonist.     

Effects of Ca channel blockers on Ca loading induced by metabolic inhibition and hyperkalemia in cardiomyocytes

The effects of the L-type (nifedipine and verapamil) and the T-type (mibefradil) Ca²⁺ channel blockers on the increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) induced by NaCN metabolic inhibition and hyperkalemia were examined in chicken cardiomyocytes using fluorescence imaging with Fura-2. NaCN induced a slow and sustained rise in [Ca²⁺]_i, which was not affected by pretreating the cells for 5 min with nifedipine, verapamil, or mibefradil at 100 nM or 10 μM. Pretreatment of the cells with 10 μM nifedipine, verapamil, or mibefradil for 5 min remarkably inhibited the K⁺-induced increase in [Ca²⁺]_i. These inhibitory effects diminished after 48-h pretreatment with nifedipine or verapamil but not with mibefradil. Ryanodine also induces an increase in [Ca²⁺]_i, and this effect was enhanced by 48-h pretreatment of the cells with 10 μM verapamil but not with 10 μM mibefradil. We conclude that the NaCN-induced increase in [Ca²⁺]_i is independent of the Ca²⁺ influx though the L-type or T-type Ca²⁺ channels. Chronic inhibition of the L-type Ca²⁺ channels but not T-type channels may enhance the ryanodine receptor-mediated Ca²⁺ release, which may be responsible for the development of tolerance to their inhibitory effects on K⁺-induced increase in [Ca²⁺]_i.     

The Protective Action of Tetrodotoxin and (±)-Kavain on Anaerobic Glycolysis, ATP Content and Intracellular Na and Ca of Anoxic Brain Vesicles

Because recent reports point to Na⁺ channel blockers as protective agents directed against anoxia-induced neuronal damage including protection of anaerobic glycolysis, the influences of tetrodotoxin (TTX) and (±)-kavain on anoxic rat brain vesicles were investigated with respect to lactate synthesis, vesicular ATP content and cytosolic free Na⁺ and Ca²⁺ ([Na⁺]_i, [Ca²⁺]_i), both of the latter determined fluorometrically employing SBFI and FURA-2, respectively. After anoxia, basal lactate production was increased from 2.9 to 9.8 nmol lactate/min/mg protein. Although lactate synthesis seemed to be stable for at least 45 min of anoxia, as deduced from the linearity of lactate production, the ATP content declined continuously with a half life (τ ) af 14.5 min, indicating that anaerobic glycolysis was insufficient to cover the energy demand of anoxic vesicles. Correspondingly, [Na⁺]_i and [Ca²⁺]_i increased persistently after anoxia by 22.1 mmol/l Na⁺ and 274.9 nmol/l Ca²⁺, determined 6.3 min after onset. An additional stimulation of vesicles with veratridine accelerated the drop of ATP (τ = 5.1 min) and provoked a massive Na⁺ overload, which levelled off to 119 mmol/l Na⁺ within a few minutes. Concomitantly, [Ca²⁺]_i increased linearly with a rate of 355 nmol Ca²⁺/l/min. Despite the massive perturbation of ion homeostasis, lactate production was unaffected during the first 8 min of veratridine stimulation. However, complete inhibition of lactate synthesis took place 30 min after veratridine was added. The Na⁺ channel blockers TTX and (±)-kavain, if applied before anoxia, preserved vesicular ATP content, diminished anoxia-induced increases in [Na⁺]_i and [Ca²⁺]_i and prevented both the veratridine-induced increases of [Na⁺]_i and [Ca²⁺]_i and the inhibition of lactate production. The data indicate a considerable Na⁺ influx via voltage-dependent Na⁺ channels during anoxia, which speeds up the decline in ATP and provokes an increase in [Ca²⁺]_i. A massive Na⁺ and Ca²⁺ overload induced by veratridine failed to influence lactate synthesis directly, but initiated its inhibition. © 1997 Elsevier Science Ltd. All rights reserved.     

Effects of isoquinoline derivatives, HA1077 and H-7, on cytosolic Ca level and contraction in vascular smooth muscle

The effects of isoquinoline derivatives, HA1077 (1-[5-isoquinolinesulfonyl]-homopiperazine) and H-7 (1-[5-isoquinoline-sulfonyl]-2-methylpiperazine), on cytosolic Ca²⁺ levels ([Ca²⁺]_i) and muscle tension were examined in vascular smooth muscle of rat aorta. High K⁺ (72.7 mM) and norepinephrine (1 μM) induced a sustained contraction with a sustained increase in [Ca²⁺]_i. HA1077 and H-7 (3–10 μM) inhibited the increse in muscle tension more strongly than the increase in [Ca²⁺]_i. Verapamil (10 μM) completely inhibited the increase in [Ca²⁺]_i and the contraction induced by K⁺ whereas it inhibited the increase in [Ca²⁺]_i more strongly than the contraction due to norepinephrine. The verapamil-insensitive portion of the norepinephrine-induced contraction was inhibited by HA1077 or H-7. In Ca²⁺-free solution, 0.1 μM norepinephrine induced a transient increase in [Ca²⁺]_i and muscle tension. The transient contraction was inhibited by 10 μM HA1077 or 10 μM H-7 without inhibiting the increase in [Ca²⁺]_i. 12-Deoxyphorbol 13-isobutyrate (DPB) (1 μM) caused a sustained contraction, and this contraction was inhibited by HA1077 and H-7 at similar concentrations needed to inhibit the contractions induced by high K⁺ or norepinephrine. In rabbit mesenteric artery permeabilized with Staphylococcus aureus -toxin, 100 μM HA1077 and 100 μM H-7 inhibited the contraction induced by 0.3 μM Ca²⁺. These results suggest that the inhibitory effects of isoquinoline derivatives, HA1077 and H-7, are due to a decrease in [Ca²⁺]_i and in the Ca²⁺ sensitivity of contractile elemenst in vascular smooth muscle.     

Heptachlor epoxide induces a non-capacitative type of Ca2+ entry and immediate early gene expression in mouse hepatoma cells

The effects of the organochlorine (OC) liver tumor promoter heptachlor epoxide (HE) and a related non-tumor promoting OC, delta-hexachlorocyclohexane (δ-HCH), on the dynamics of intracellular calcium (Ca²⁺) were investigated in mouse 1c1c7 hepatoma cells. HE induced a non-capacitative, Ca²⁺ entry-like phenomenon, which was transient and concentration-dependent with 10 and 50 μM HE. The plasma membrane Ca²⁺ channel blocker SKF-96365 antagonized this HE-induced Ca²⁺ entry. δ-HCH failed to induce Ca²⁺ entry, rather it antagonized the HE-induced Ca²⁺ entry. Both HE and δ-HCH induced Ca²⁺ release from endoplasmic reticulum (ER) at treatment concentrations as low as 10 μM; at 50 μM, the former induced 5× as much Ca²⁺ release as the latter. The HE-induced Ca²⁺ release from the ER was antagonized using the IP₃ receptor/channel blocker xestospongin C, suggesting that HE induces ER Ca²⁺ release through the IP₃ receptor/channel pore. These results show that the effect of HE on cellular Ca²⁺ mimics that of mitogens such as epidermal and hepatocyte growth factors. They also provide insight into the similarities and differences between tumorigenic and non-tumorigenic OCs, in terms of the mechanisms and the extent of the [Ca²⁺]_i increased by these agents.