ADP和CPA诱导的高血压病人血小板胞浆游离钙的变化

[目的]探讨高血压病人血小板胞浆游离钙浓度(cytoplasmicfreeCa2 concentration,[Ca2 ]i)的变化.[方法]采用Fura-2/Am荧光双波长测定[Ca2 ]i技术,动态观察激动剂二磷酸腺苷(adenosinediphosphate,ADP)和环匹阿尼酸(cyclopiazonicacid,CPA)对高血压病人血小板[Ca2 ]i的影响.[结果]高血压病人静息血小板[Ca2 ]i与正常人比较明显增高(P<0.05);ADP和CPA激动的高血压病人的血小板平台钙与静息钙比较有统计学意义(P<0.05);峰位钙-平台钙的差(既钙释放)与正常人比较明显增高(P分别<0.05和<0.01);平台钙-静息钙的差(既钙内流)与正常人比较无明显差异(P>0.05).[结论]高血压病人静息血小板[Ca2 ]i增高,平台钙水平明显增高,血小板呈高反应状态;高血压病人的血小板被ADP和CPA激活不能恢复至静息动状态;ADP和CPA激动的高血压病人的血小板钙释放增多,钙内流正常.     

尼氟灭酸对糖尿病人血小板胞浆游离钙及聚集功能的影响

【目的】探讨糖尿病人血小板胞浆游离钙([Ca2+]i)、血小板聚集率变化及氯通道阻断剂尼氟灭酸对其的影响。【方法】用Fura-2荧光测钙技术检测血小板[Ca2+]i,血小板聚集仪检测血小板聚集率,观察氯通道阻断剂尼氟灭酸、钙通道阻断剂硝苯地平及两者联合对糖尿病人的血小板[Ca2+]i、血小板聚集率的作用。【结果】①糖尿病人血小板聚集率为(74.9±13.7)%,高于正常人(P<0.05);糖尿病人的静息血小板[Ca2+]i值、钙释放、钙內流分别为(124．5±38．1)nmol／L、(497．1±95．1)nmol/L、(354.3±75.0)nmol/L,均高于正常人(P均<0.05);②尼氟灭酸及硝苯地平抑制血小板钙内流呈浓度依赖性,半数抑制浓度(IC50)的尼氟灭酸(50μmol/L)对糖尿病人血小板钙内流的抑制率为(54.7±14.5)%,对血小板聚集率的抑制率为(32.3±21.4)%;IC50的硝苯地平(7.5μmol/L)对糖尿病人血小板钙内流的抑制率为(17.9±11.9)%,对血小板聚集率的抑制率为(32.3±20.4)%;③尼氟灭酸联合硝苯地平对糖尿病人血小板钙有抑制作用,联合作用时尼氟灭酸对钙内流抑制率为(51.9±12.8)%;硝苯地平对钙内流抑制率为(12.4±8.5)%(P均<0.05),两者间不存在交互效应。【结论】糖尿病人血小板聚集率、静息血小板[Ca2+]i及钙运动均高于正常人,血小板呈高反应状态。尼氟灭酸可抑制糖尿病人血小板聚集和钙内流,可能与血小板膜存在对尼氟灭酸敏感的氯通道有关。尼氟灭酸与硝苯地平联合对糖尿病患者的血小板钙运动无协同及遏制作用。     

GPⅡb/Ⅲa受体拮抗剂RGDS对血小板聚集和胞浆游离钙的影响

[目的]探讨血小板GPⅡb/Ⅲa受体拮抗剂RGDS对血小板聚集和血小板[Ca2+]i的影响.[方法]比浊法测定PAG;采用Fura-3/AM荧光探针标记血小板胞浆钙离子,使用共聚焦显微镜观察单个血小板荧光强度的变化,计算机图像系统分析血小板[Ca2+]i的变化.[结果]凝血酶(0.03 U/mL)为激动剂时,血小板PAG(M)为(78.2±12.4)%.在所取的62.5～1 000μmol/L RGDS内的5种浓度下,RGDS可呈浓度依赖性地抑制凝血酶诱导的PAG(M).正常人静息血小板[Ca2+]i荧光强度值为376.1±70.5;凝血酶(0.03 U/mL)激动的血小板[Ca2+]i荧光强度值升高为977.9±108.8;GPⅡb/Ⅲa受体拮抗剂RGDS(250 μmol/L)对静息血小板的[Ca2+]i荧光强度值无抑制作用;GPⅡ b/Ⅲa受体拮抗剂RGDS(250μmol/L)作用于血小板后,凝血酶(0.03 U/mL)激动的血小板[Ca2+]i荧光强度值升高受到抑制,抑制率为(9.37±7.5)%.[结论]凝血酶(0.03 U/mL)可以引起血小板的聚集和血小板[Ca2+]i的升高.GP Ⅱb/Ⅲa受体拮抗剂RGDS可以抑制凝血酶(0.03 U/mL)引起的血小板聚集和[Ca2+]i的升高.     

马钱子碱抗血小板聚集及其对凝血酶诱导血小板内游离钙的变化

①以Born和O′Brien法进行血小板聚集实验,可见马钱子碱(Brucine,B)和士的宁(Strychnine,S)各10~(-5)～10~(-3)mol/L明显抑制ADP、Epi和Thrombin诱导的人血小板聚集作用,呈剂量依赖性。②用Fura-2/AM检测B对Thrombin诱导人血小板内游离钙[Ca~(2+)]i的变化。结果:静息[Ca~(2+)]i值为111.14±11.71nmol/L(n=12)。Thrombin诱导的[Ca~(2+)]i峰值为1015±36.38nmol/L。B10~(-4)、10~(-3)mol/L分别使Thrombin诱导的[Ca~(2+)]i值下降至328.68±17.81和94.17±4.9nmol/L。在EGTA螯合血小板外钙[Ca~(2+)]o情况下,Thrombin诱导的[Ca~(2+)]i峰值为218.55±56.2nmol/L与静息[Ca~(2+)]i相比具有非常显著差异(P<0.01),提示Thrombin促血小板内钙释放;B10~(-4)、10~(-3)mol/L分别使其[Ca~(2+)]i值下降至89.93±6.31和75.49±4.37nmol/L,上述结果提示:B抑制Thrombin的促外钙内流及内钙释放,呈剂量依赖性。     

M_3受体激动剂胆碱对大鼠心肌细胞内钙离子的影响

目的研究M3受体激动剂胆碱对大鼠心肌细胞内钙离子的影响。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(LSCM)上测定细胞[Ca2+]i的变化。结果胆碱不影响静息状态下的细胞[Ca2+]i,对咖啡因和三磷酸肌醇(IP3)介导的细胞内钙的释放均无作用。5.0 mmol/L胆碱可以抑制KCl除极诱导的心肌[Ca2+]i的升高幅度,2.0 nmol/L 4-DAMP可以阻断这一作用。结论 M3受体激动剂胆碱通过阻断心肌细胞膜电压依赖性钙通道降低心肌细胞[Ca2+]i,从而发挥心肌保护作用。     

血浆钙离子浓度对血小板聚集的影响

目的 探讨血浆钙离子浓度对血小板聚集检验结果的影响.方法 采集健康志愿者静脉血标本(n=42),添加不同量的氯化钙,采用血浆比浊法进行血小板聚集率检测.结果 血浆Ca2+浓度在2.1-0.12mmol/l时,二磷酸腺苷(ADP)和花生四烯酸(AA)诱导的血小板聚集率分别为(75.9±10.4)％-(51.8±9.6)％和(83.7±13.9)％-(64.4±12.2)％,血小板聚集率随Ca2+浓度的降低而降低;血浆Ca2+浓度在2.1-33.66mmol/L时,ADP和AA诱导的血小板聚集率分别为(75.9±10.4)％-(94.7士4.8)％和(83.7士13.9)％-(93.2±5.5)％,随Ca2+浓度的增高而增高;Ca2+浓度为39.00mml/L时,血小板聚集率明显降低[ADP和AA诱导的血小板聚集率分别为(9.1±5.3)％和(11.1±4.5)％,均P＜0.01].结论 钙离子浓度波动对血小板聚集检验结果有明显影响.低于生理钙浓度(2.1mmol/L血小板聚集率随Ca2+浓度的降低而降低,高于生理钙浓度血小板聚集率随Ca2+浓度的增高而增高;血钙过高(≥39.0mmol/L)抑制血小板聚集.     

三磷酸腺苷引起大鼠三叉神经节胞内钙离子信号转导机制的研究

目的探讨三磷酸腺苷(ATP)对三叉神经痛大鼠感觉神经元内钙离子浓度([Ca2+]i)的影响及其信号转导机制。方法 SD大鼠眶下神经缩窄造成三叉神经痛模型,造模后1周处死大鼠,取出三叉神经节(TG),分离出完整的小直径神经元(﹤600μm2)用于钙离子成像,通过使用荧光染料来标记相关激动剂,检测毒胡萝卜内酯(Tg,1μmol/L)、咖啡因(Caff,20 mmol/L)和ATP(100μmol/L)作用下TG小直径神经元内[Ca2+]i变化。结果①在正常外液和无钙外液中,在大鼠TG小直径神经元上分别给予Tg、Caff和ATP均能够引起[Ca2+]i不同程度升高;②在无钙外液中,ATP引起的TG神经元[Ca2+]i升高可被Tg可逆性地抑制(n=8,P<0.01);③在无钙外液中,ATP引起的TG神经元[Ca2+]i升高可被P2受体阻断剂苏拉明(suramin,100μmol/L)明显抑制;④在正常外液中,Tg引起TG神经元[Ca2+]i升高,当升高达到最大后再次给予ATP,仍然能引起[Ca2+]i进一步升高。结论在大鼠TG神经元中同时存在IP3敏感钙库和ryanodine敏感钙库。ATP可通过两种途径引起细胞内[Ca2+]i升高,一种途径是激动P2Y受体引起IP3敏感钙库的Ca2+释放,另一种途径是激动P2X受体引起细胞外Ca2+内流。在无钙外液中,ATP引起的TG神经元[Ca2+]i升高是通过IP3敏感钙库释放引起的。     

应用Fura-2/AM荧光双波长法研究抑肽酶对血小板活化的保护作用

目的探讨抑肽酶对血小板活化的保护机制.方法用钙荧光指示剂Fura-2/AM负载人洗涤血小板,用荧光双波长分光光度计比值法测定静息血小板胞浆游离钙浓度([Ca2 ]i)及凝血酶、抑肽酶对[Ca2 ]i的影响.结果在生理胞外Ca2 浓度时,正常人血小板[Ca2 ]i静息水平为(151.840±28.719)nmol/L,凝血酶可引起血小板[Ca2 ]i的明显增加(P＜0.01),抑肽酶呈剂量依赖性地抑制由凝血酶引起的[Ca2 ]i的增加(P＜0.01).结论抑肽酶的保护血小板机制与其抑制血小板内[Ca2 ]i动员等信息传递过程有关.     

血管紧张素Ⅱ受体基因敲除对跨膜钙内流的作用

目的　观察血管紧张素Ⅱ受体亚型 (AT1a)基因敲除对跨膜钙内流的影响。方法　培养AT1a基因敲除及其野生型对照小鼠的主动脉血管平滑肌细胞 (VSMC)和应用荧光倒置显微镜及钙荧光指示剂Fura 2 /AM动态观测VSMC的钙离子 [Ca2 ]i变化。结果　在血管紧张素Ⅱ (AngⅡ )刺激下钙内流显著增加 ,AT1a 敲除组VSMC钙净增值为 ( 2 0 4± 2 2 )nmol/L、基础 [Ca2 ]i为 ( 10 8± 9)nmol/L野生型对照VSMC钙净增值为 [( 194± 19)nmol/L ,基础 [Ca2 ]i为 ( 110± 7)nmol/L](P <0 0 1) ,应用钙通道阻滞剂硝苯啶和三磷酸鸟苷 γs能明显抑制AngⅡ介导的细胞钙增加 ,但G抑制蛋白的阻断剂百日咳毒素却能明显增强AngⅡ介导的细胞钙增加。结论　AT1a基因敲除后 ,AngⅡ介导的钙内流主要通过L 型钙通道 ,并受百日咳毒素的调节。     

弓形虫速殖子细胞质游离钙浓度的测定

目的研究弓形虫与宿主细胞之间相互作用的钙通道机制.方法以急性期感染小鼠腹水收集的RH株刚地弓形虫速殖子为材料,采用荧光染料Fura-2与细胞质游离钙结合,通过荧光分光光度计技术和Super Ion Probe Software计算机软件测定弓形虫速殖子细胞质游离钙浓度([Ca2+]i).结果正常弓形虫速殖子[Ca2+]i为(205.02±18.6)nmol/L,符合文献报道的静息状态下真核细胞[Ca2+]i浓度范围.结论本方法简便、易行,相对费用低,适用于国内实验室.     

EFFECT OF 764－3 ON AGGREGATION AND CALCIUM MOVEMENTS IN AEQUORIN－LOADED HUMAN PLATELETS

ＥＦＦＥＣＴＯＦ７６４－３ＯＮＡＧＧＲＥＧＡＴＩＯＮＡＮＤＣＡＬＣＩＵＭＭＯＶＥＭＥＮＴＳＩＮＡＥＱＵＯＲＩＮ－ＬＯＡＤＥＤＨＵＭＡＮＰＬＡＴＥＬＥＴＳＷｕＨｕａｉｚｈｕ武怀珠；ＬｉＪｉａｚｅｎｇ李家增；ＰｅｎｇＬｉｎ彭林；ＴｅｎｇＢｉｎ滕彬ａｎｄＺ...     

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

Hypoxic pul monary hypertension ( HPH) ischaracterized by an elevation of pul monary vascularreaction and pul monary vascular reconstruction.Cytoplasmic free Ca2 concentration ([ Ca2 ]i)plays a key role in the regulation of vascular tone ,pul monary vasoconstriction and proliferation ofsmooth muscle cells[1]. The present study evalua-ted the role of [Ca2 ]iin the regulation of pul mo-nary vascular tone through regulation of calcium-activated chloride (Clca) channels in rats under a-cute h…     

Effects of total flavone of Abelmoschl Manihot L. Medic on the function of platelets and its mechanism

Total flavone of Abelmoschl Manihot L.Med ic (TFA) is a flavonol glycoside. It is extractedfrom yellow mallow of the Chinese mallow section.Its main composition is hyperin, quercetin, etc.Some studies showed that hyperin had an effect onthe inhibition of Ca2+ influx(1) and that quercetininhibited platelet aggregation and the rise of[Ca2+]i in platelets(2). Our previous study showedTFA had protection effects against cerebral ische mia reperfusion in mice an…     

Effects of nerve growth factor on intracellular free Ca2+ in oxygen/glucose-deprived cultures from cerebral cortex of fetal rats

ＩｔｉｓｗｅｌｋｎｏｗｎｔｈａｔｔｈｅｉｎｔｒａｃｅｌｕｌａｒＣａ２＋ｐｌａｙｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｂｏｔｈｐｈｙｓｉｏｌｏｇｉｃａｌａｎｄｔｏｘｉｃｏｌｏｇｉｃａｌｐｒｏｃｅｓｓｅｓ．ＡｄｉｓｒｕｐｔｉｏｎｏｆＣａ２＋ｈｏｍｅｏｓｔａ...     

葛根素对高血压大鼠血小板游离钙浓度、聚集率和心脏重塑的影响

目的研究葛根素对自发性高血压大鼠(SHR)血小板游离钙浓度([Ca2+]i)、血小板聚集率(Pag)和心脏重塑的影响。方法18只10月龄伴有左心室肥厚(LVH)的SHR随机分为葛根素组、福辛普利组和生理盐水组(NS组)3组,每组6只。并设Wistar大鼠6只作为正常对照组。实验各组进行为期8周的干预治疗,观察其对SHR收缩压、心率、左心室肥厚指数、血小板胞浆[Ca2+]i和Pag的影响。结果6只SHR干预前的收缩压、左心室肥厚指数、血小板胞浆[Ca2+]i和Pag均显著高于同龄Wistar大鼠(P<0.01),血小板胞浆[Ca2+]i和Pag与左心室肥厚指数呈显著正相关(P<0.01)。干预8周后,葛根素组、福辛普利组与NS组比较,均能显著降低左心室肥厚指数、血小板胞浆[Ca2+]i和Pag(P<0.01)。结论血小板内钙代谢和血小板聚集率异常可能在SHR心脏重塑中起重要作用。葛根素能显著降低SHR的血小板胞浆[Ca2+]i和Pag,从而改善SHR心脏重塑。     

D-AP5 blocks the increase of intracellular free Ca2+ induced by glutamate in isolated cochlear IHCs

Objective To investigate the effect of D-AP5 (D-2-amino-5-phosphonopentanoate, a spec ific NMDA-antagonist) on the increase of intracellular free Ca(2+) concent ration (［Ca(2+)］(i)) induced by glutamate in isolated cochlear inner hair cells (IHCs), and to detect the autoreceptors of the IHC membrane. Methods When a laser scanning confocal microscope (LSCM) was used, the exogenous glutama te (Glu) -induced changes in ［Ca(2+)］(i) of isolated IHCs and OHCs of guinea pig c ochlea were observed with fluo-3, a fluorescent probe for ［Ca(2+)］(i).A fter D-AP5 or CNQX (6--cyano--7--nitroguinoxaline--2, 3--dione, a sp ecific AMPA- antagonist) was administrated, the exogenous glutamate (Glu)-indu ced changes in ［Ca(2+)］(i) of isolated IHCs were recorded.Results In the presence of a low concentration Glu (3. 85 μmol/L), there was an inc rease of ［Ca(2+)］(i) in IHCs, whereas there was no change in OHCs.W hen 50 μmol/L of D-AP5 was administrated in advance, Glu did not induce a corresponding increase in ［Ca(2+)］(i) in IHCs, and 50 μmol/L of CNQX did not completely block the increase of ［Ca(2+)］(i) in IHCs.Conclusions These results suggest that the autoreceptors existing in the IHC membrane are m ainly of NMDA type, while there are relatively few AMPA receptors.Exogenou s Glu is capable of increasing ［Ca(2+)］(i) in IHCs by acting on the NMDA autoreceptor of IHCs in a positive feedback manner.     

加巴喷丁对SNL模型大鼠损伤DRG神经元细胞内[Ca2+]i的影响

目的:探讨加巴喷丁对脊神经结扎(SNL)模型大鼠损伤背根神经节神经元胞内游离钙浓度的影响?方法:SD大鼠,雄性35只,4~6周龄,采用左侧L5 SNL术制备大鼠神经病理性疼痛模型?于结扎后15 d采用酶消化法急性分离损伤同侧L5背根神经节神经元(SNL组)和假手术组L5背根神经节神经元(Sham组)?采用流式细胞仪检测10?100和300 μmol/L浓度加巴喷丁对损伤侧L5背根神经节神经元基础及高K+激发胞内游离钙浓度的影响?结果:加巴喷丁剂量依赖性地抑制高钾激发的胞内游离钙浓度的增加(P < 0.05或P < 0.01),但对静息钙无作用?结论:加巴喷丁对神经病理性疼痛大鼠损伤背根神经节神经元高钾激发的钙内流的抑制作用,可能与其抗伤害作用的外周机制相关?     

莪术二酮抑制凝血酶诱导血小板活化和聚集的研究

目的 研究莪术二酮对凝血酶诱导大鼠血小板活化和聚集的影响,来阐明莪术二酮抗血小板活化的机制.方法 电阻抗法测定凝血酶诱导大鼠洗涤血小板聚集率,计算莪术二酮对其抑制率.荧光分光光度法测莪术二酮抑制血小板胞内钙离子浓度变化.流式细胞术检测血小板P-selectin(CD62p)的表达.Western blot测定磷酸化蛋白的磷酯酶C(PLC)、蛋白激酶C(PKC)和丝裂原活化蛋白激酶(MAPKs)的变化.结果 400 μmol/L的莪术二酮可以有效地抑制0.3 U/ml凝血酶诱导的大鼠血小板的聚集.50、100 μmol/L的莪术二酮可以显著抑制血小板活化标志物[Ca2+]i上升和P-selectin(CD62p)的表达.在蛋白水平上,莪术二酮可以抑制PLCβ3、PKCθ和MAPKs蛋白的磷酸化.结论 初步认为莪术二酮通过PLC-PKC-MAPKs通路抑制凝血酶诱导的血小板活化和聚集,阐明了莪术二酮抗血小板活化的部分机制.     

Pathogenesis and the role of Ca2+ overload during myocardial ischemia/reperfusion

To study the regulation of [Na+]i and [Ca2+]i during myocardial ischemia/reperfusion, [Na+]i and [Ca2+]i were measured simultaneously using guinea pig ventricular myocytes which were dual-loaded with SBFI/AM and fluo-3/AM. It was suggested that: (1) [Na+]i increased during metabolic inhibition (MI: 3.3 mM amytal and 5 microM CCCP) by both the activated Na+ influx via Na+/H+ exchange and the suppressed Na+ extrusion via the Na+/K+ pump; (2) Na+/Ca2+ exchange was inhibited during MI, causing the dissociation between [Na+]i and [Ca2+]i; (3) Na+/Ca2+ exchange could be reactivated by energy repletion, resulting in a significant increase in [Ca2+], Furthermore, a Ca2+ influx via the reverse-mode of Na+/Ca2+ exchange may play a key role in the mechanism of Ca2+ overload on reoxygenation; and (4) cell contracture during MI was related to rigor due to energy depletion, while cell contracture after energy repletion was likely to be related to Ca2+ overload.     

Lead Can Inhibit NMDA^—,K^＋—,QA／KA—Induced Increases in Intracellular Free Ca^2＋ in Cultured at Hippocampal Neurons

Objective To examine the effects of Pb2+ on N-methyl-D-aspartate (NMDA)-, K+- and quisqualate(QA)/kainite(KA)-induced increases in intracellular free calcium concentration ([Ca2+]i) in cultured fetal rat hippocampal neurons in order to explain the cognitive and learning deficits produced by this heavy metal. Methods Laser scanning confocal microscopy was used. Results The results clearly demonstrated that adding Pb2+ before or after NMDA/glycine stimulation selectively inhibited the stimulated increases in [Ca2+]i in a concentration-dependent manner. In contrast, Pb2+ treatment did not markedly affect increases in [Ca2+]i induced by an admixture of QA and KA. The minimal inhibitory effect of Pb2+ occurred at 1 μ mol/L, and more than seventy percent abolition of the NMDA-stimulated increase in [Ca2+]iwas observed at 100 μmol/L Pb2+. Evaluation of pb2+-induced increase in [Ca2+]i response to elevating extracellular concentrations of NMDA, glycine or calcium revealed that Pb2+ was a noncompetitive antagonist of both NMDA and glycine, and a competitive antagonist of Ca2+ at NMDA receptor channels. In addition, Pb2+ inhibited depolarization-evoked increases in [Ca2+]i mediated by K+ stimulation (30 μmol/L), indicating that Pb2+ also depressed the voltage-dependent calcium channels. Also, the results showed that Pb2+ appeared to be able to elevate the resting levels of [Ca2+]i in cultured neurons, implying a reason for pb2+-enhanced spontaneous release of several neurotransmitters reported in several previous studies. Conclusion Lead can inhibit NMDA-, K+-, QA/KA-inducod increases in intracellular [Ca2+]i in cultured hippocampal neurons.