右美托咪定对快速心房起搏后兔心房电生理学特性及Cx43 Cx40表达的影响

目的 探讨右美托咪定对快速心房起搏后兔心房电生理学特性及Cx43、Cx40表达的影响。方法 选择成年雄兔24只,随机分为对照组（C组）、快速心房起搏组（RAP组）与快速心房起搏+右美托咪定灌流组（RAP+DEX组）,每组8只。制备Langendorff离体心脏灌注模型,通过快速心房起搏构建房颤模型。分别检测3组心房90%单相动作电位复极时程（MAPD₉₀）、心房有效不应期（ERP）、ERP与MAPD₉₀比值（ERP/MAPD₉₀）、房颤诱发率及持续时间,取心房组织,采用Western-bolt法和免疫荧光法检测Cx43、Cx40的蛋白含量和分布。结果 T₁~T₃时,3组MAPD₉₀比较,差异有统计学意义（P<0.05）。RAP组MAPD₉₀随时间的推移有逐渐下降趋势（P<0.05）,不同的处理方式和时间对MAPD₉₀有交互作用（P<0.05）。T₃时,RAP组ERP、ERP/MAPD₉₀、Cx43和Cx40蛋白含量均低于C组和RAP+DEX组,房颤诱发率高于C组和RAP+DEX组,差异有统计学意义（P<0.05）。3组房颤持续时间比较,差异无统计学意义（P>0.05）。电镜下,RAP组Cx43和Cx40分布不规律且侧面分布增多,而C组和RAP+DEX组Cx43和Cx40分布较规律且主要集中在两端。结论 右美托咪定可抑制房颤时的心房电重构,降低房颤的易感性,其机制可能与其抑制Cx43、Cx40的表达下调和再分布有关。     

北豆根胶囊中蝙蝠葛碱和蝙蝠葛苏林碱的定量分析

目的：建立北豆根胶囊中蝙蝠葛碱和蝙蝠葛苏林碱的定量分析方法。方法：采用高效液相色谱法测定北豆根胶囊中蝙蝠葛碱和蝙蝠葛苏林碱的含量并制定含量限度要求。高效液相色谱条件：以十八烷基硅烷键合硅胶为填充剂;以乙腈-0．05％三乙胺溶液（45：55）为流动相;检测波长为284nm。结果：北豆根胶囊中蝙蝠葛碱和蝙蝠葛苏林碱线性范围依次为0．2314～2．314ug（r=0．9999）,0．116～1．16ug（r=0．9999）;平均回收率（n=6）依次为104．9％（RSD=1．9％）,101．7％（RSD=1．4％）;北豆根胶囊中蝙蝠葛碱和蝙蝠葛苏林碱的总量应不低于22．0mg／pergranule。结论：本方法操作简便,结果准确,提高了北豆根胶囊的质量控制标准,为其临床用药的安全性和有效性提供了质量保证。     

关白附总碱盐抗大鼠房颤作用

目的观察关白附总碱盐抗房颤作用。方法雄性SD大鼠,随机分组,CaCl210mg/mL+ACh 66μg/mL混合液iv诱发大鼠房颤,连续7d,于大鼠造模第4天起,关白附治疗组po 5、15、45mg/kg,绝奈达隆1mg/kg ip,每天1次,正常组静脉注射生理盐水7d。心电图监测大鼠房颤持续时间及QTc。7d后,测定大鼠心房肌有效不应期,western-blot法测定心房肌缝隙连接蛋白Cx40的表达。结果 Ach-CaCl2连续静脉注射引起大鼠房颤持续时间逐渐延长,与正常组比,心房有效不应期缩短(P<0.01),心房肌Cx40含量下降(P<0.05)。关白附能有效抑制房颤持续时间,延长心房ERP,保护心房Cx40表达。结论关白附能有效对抗房颤,改善房颤引起的电重构。     

蝙蝠葛碱对急性心肌梗死患者血小板聚集性的影响

目的　探讨蝙蝠葛碱 (DAU )对急性心肌梗死 (AMI)患者血小板不可逆性聚集的作用。方法　用流式细胞仪测定AMI患者 (n =12 )静息状态及凝血酶 (5 0、10 0、5 0 0、10 0 0U·L-1)激活时 ,血小板膜表面糖蛋白Ⅳ (GPIV)及凝血酶敏感蛋白 (TSP )分布状况 ,并与健康人 (n =14)比较。结果　AMI患者静息及激活状态血小板膜表面GPⅣ ,TSP分布高于健康人 (P <0 0 5 ,0 0 1) ;DAU(5 0 μmol·L-1)可抑制 5 0U·L-1,10 0U·L-1及 5 0 0U·L-1凝血酶诱导的血小板膜GPⅣ再分布及血小板内TSP释放 (P <0 0 5 ,0 0 1) ,不能抑制10 0 0U·L-1凝血酶诱导的血小板膜GPⅣ再分布及血小板内TSP释放。结论　AMI患者血小板活性及对凝血酶的反应性增高 ,DAU可减少AMI患者血小板不可逆性聚集的发生。     

RP-HPLC法测定北豆根药材中5个生物碱的含量

目的:采用RP-HPLC法同时测定中药材北豆根中青藤碱、蝙蝠葛苏林碱、蝙蝠葛诺林碱、蝙蝠葛新诺林碱和蝙蝠葛碱5种生物碱的含量。方法:采用色谱柱Welchrom-C18(250 mm×4.6 nm,5 mm),以甲醇(A)-乙腈(B)-0.4%二乙胺水溶液(C)为流动相,梯度洗脱[0～13 min,A-B-C(18:20:62);13～45 min,A-B-C(18:20:62)→A-B-C(37:20:43);45～60min,A-B-C(37:20:43)];流速1.0 mL·min-1;检测波长为285 nm。结果:青藤碱、蝙蝠葛苏林碱、蝙蝠葛诺林碱、蝙蝠葛新诺林碱和蝙蝠葛碱5种生物碱的线性范围分别为0.016～0.2μg(r=0.9995),0.029～0.363μg·mL-1(r=0.9996),0.09～1.125μg·mL-1(r=0.9996),0.336～4.2μg·mL-1(r=0.9997)与0.172～2.15μg·mL-1(r=0.9996);加样同收率(n=6)分别为99.2%,98.5%,102.2%,96.5%和98.4%。结论:该方法简便、快速、准确,重复性好,可以用于北豆根药材及其制剂的含量测定。     

高效液相色谱法同时测定蝙蝠葛酚性碱片中蝙蝠葛碱和蝙蝠葛苏林碱含量

目的建立同时测定蝙蝠葛酚性碱片中蝙蝠葛碱和蝙蝠葛苏林碱含量的HPLC法。方法采用Diamonsil C18色谱柱（4．6mm×200mm,5μm）;流动相：乙腈-4％冰醋酸-三乙胺（40：220：1．5）;流速：1．0mL·min^-1,检测波长：282nm;柱温：30℃。结果蝙蝠葛碱和蝙蝠葛苏林碱的线性范围分别为9．28-92．8μg·mL^-1（R=0．9999）和2．8～28．0μg·mL^-1（R=0．9999）。平均回收率分别为97．7％（RSD=1．1％）和99．4X（RSD=2．0％）。结论本方法简便、准确、灵敏度高、重现性好,可作为蝙蝠葛酚性碱片的质量控制方法之一。     

RP-HPLC法测定北豆根药材中4种生物碱的含量

目的:采用 RP-HPLC 法同时测定巾药材北豆根中青藤碱、蝙蝠葛苏林碱、蝙蝠葛碱和粉防己碱4种生物碱的含量。方法:采用 Agilent Eclipse XDB-C_(18)色谱柱(250 mm×4.6 mm,5μm);以甲醇(A)-乙腈(B)-0.05%乙胺的水溶液(C)为流动相,梯度洗脱[0～20 min,B-C(20:80);20～40 min],B-C(20:80)→A—B—C(5:40:55);40～60 min,A-B-C(5:40:55)→B,保持10 min];流速1.0 mL·min~(-1);检测波长为262 nm(0～20 min),282 nm(20～70 min)。结果:青藤碱、蝙蝠葛苏林碱、蝙蝠葛碱和粉防己碱4种生物碱的线性范围分别为0.09～0.43μg(r=0.9997)、0.62～3.09μg(r=0.9995)、0.78～3.88μg(r=0.9996)与0.12～0.57μg(r=0.9997);加样同收率(n=5)分别为98.3%,97.6%,98.0%,97.8%。结论:该方法简便、快速、准确,重复性好,可以用于北豆根药材及其制剂的质量分析。     

高频刺激右心耳引起家兔慢性心房颤动

目的 探讨以高频率起搏刺激右心耳建立家兔慢性心房颤动模型的方法.方法 20只家兔随机分为实验组及对照组,对照组为假手术组.植入起搏电极但不起搏;实验组10只家兔予开胸植入双极电极并予以(800次/min)刺激右心耳30d,4h/d,术后定期监测起搏、心房颤动的发生情况,同时测定起搏前及房颤发生后心房有效不应期(AERP)的变化.结果 实验组均完成了实验,术后第7d,7只(70%),兔发生了房颤,2周时共有8只(80%)发生了房颤并能稳定维持(与对照组比较,P<0.01),30 d时仍示房颤,其余2只兔至30d时仍呈起搏心律;对照组则未发生任何心律失常情况.AERP缩短,AERP频率适应不良,与基础状态相比有显著意义.结论 长期高频率起搏刺激家兔右心耳是建立慢性房颤模型的有效方法.     

丹参酮Ⅱ-A磺酸钠对家兔心房动作电位及快速起搏所致心房电重构的影响

目的研究丹参酮ⅡA磺酸钠(TSN)对家兔在体心房单相动作电位(AMAP)及短期快速心房起搏时电重构的影响,探讨其防治房颤的可能机制。方法家兔24只,随机分为对照组与TSN组各12只。将电极经颈内静脉置入右心房记录AMAP,观察基础状态下、给药后0.5 h及以600次.m in-1心房快速起搏后0.5 h、8 h AMAP及其频率适应性的变化。结果与起搏前相比对照组AERP200 m s在起搏后0.5h缩短21.2 m s,起博后8h缩短21.6m s(P<0.05),且心房肌的频率适应性丧失。TSN在基础状态下对AMAPA、AMAPD无明显影响,但使AERP200 m s由(105.9±3.8)m s延长至(114.7±7.2)m s(P<0.05)。起搏后TSN组维持原有的心房肌频率适应性。结论快速心房起搏使心房肌的频率适应性丧失而致电重构,TSN能通过抑制L-型钙通道减轻短期快速心房起搏所致电重构。     

HPLC法对不同产地北豆根中蝙蝠葛碱的测定

目的　研究不同产地北豆根中蝙蝠葛碱含量的差异。方法　以北豆根饮片为分析对象,用phenomenexC18(4 . 6mm×15 0mm,5 μm)色谱柱,采用乙腈和0 . 2 %磷酸洗脱,流速1. 0ml·min-1,检测波长为2 84nm,对北豆根中的蝙蝠葛碱进行定性定量测定。结果　东北北豆根药材中生物碱含量最高,其次是山东产北豆根,河北产北豆根药材中蝙蝠葛碱含量较低。结论不同产地北豆根药材所含生物碱在质和量两方面均有较大差异。     

Effects of selective mineralocorticoid receptor antagonism on atrial ion currents and early ionic tachycardia-induced electrical remodelling in rabbits

Over the past years, the importance of the renin–angiotensin–aldosterone system in atrial fibrillation (AF) pathophysiology has been recognised. Lately, the role of aldosterone in AF pathophysiology and mineralocorticoid receptor (MR) antagonism in “upstream” AF treatment is discussed. Hypothesising that selective MR antagonism might also influence atrial ion currents (L-type calcium current [I _Ca,L], transient outward potassium current [I _to], sustained outward potassium current [I _sus]) and their tachycardia-induced remodelling, the effects of an eplerenone treatment were studied in a rabbit model. Six groups each with four animals were built. Animals of the control group received atrial pacing leads, but in contrast to the pacing groups, no atrial tachypacing (600 per minute for 24 and 120 h immediately before heart removal) was applied. Animals of the eplerenone groups were instrumented/paced as the corresponding control/pacing groups, but were additionally treated with eplerenone (7 days before heart removal). Atrial tachypacing was associated with a reduction of I _Ca,L. I _to was decreased after 24 h of tachypacing, but returned to control values after 120 h. In the absence of rapid atrial pacing, MR antagonism reduced I _Ca,L to a similar extent as 120 h of tachypacing alone. Based on this lower “take-off level”, I _Ca,L was not further decreased by high-rate pacing. I _to and its expected tachycardia-induced alterations were not influenced by MR antagonism. In our experiments, selective MR antagonism influenced atrial I _Ca,L and its tachycardia-induced alterations. As changes of I _Ca,L are closely linked with atrial calcium signalling, the relevance of these alterations in AF pathophysiology and, accordingly, AF treatment is likely and has to be further evaluated.     

依贝沙坦对慢性房颤犬模型心房电重构的影响

目的:观察慢性房颤后的心房电重构(AER)现象并探讨其电生理机制,以及依贝沙坦对AER的影响,为房颤治疗提供进一步的理论基础和资料。方法:建立右心房高速起搏(500次/min)2周的慢性房颤犬模型,分为对照组(假手术组)、起搏组和药物组(起搏 依贝沙坦)3组,每组各6只犬。将6对双极记录电极分别缝于高位左、右和低位左、右心房外膜以及左、右心耳,采用心脏程序期前刺激法(S1S2),分别测量基础起搏周长为300、250和200ms时的心房有效不应期(AERP)、AERP频率适应性、AERP离散度、房颤诱发率及平均持续时间等电生理指标。结果:与对照组比较,起搏组的AERP显著缩短、频率适应性不良、AERP离散度增高、继发性房颤诱发率增高且持续时间延长(P<0.01),而药物组差异无统计学意义(P>0.05)。结论:2周快速心房起搏可导致实验犬的AER,依贝沙坦可有效地阻止AER的发生。     

Effects of spironolactone on atrial structural remodelling in a canine model of atrial fibrillation produced by prolonged atrial pacing

Background and purpose:

Suppression of the renin-angiotensin-aldosterone system can prevent atrial fibrillation (AF) by attenuating atrial structural remodelling but the role of aldosterone in AF prevention has not been investigated thoroughly. We explored whether the aldosterone antagonist, spironolactone, could improve atrial structural remodelling in long-term rapid pacing-induced AF.

Experimental approach:

Three groups of dogs were used, sham-operated, control and spironolactone-treated groups. Dogs in the control and spironolactone groups had right atrial pacing for 6 weeks. The spironolactone group was given spironolactone 1 week before and during the atrial pacing. After 6 weeks of pacing, atrial structural and functional changes were assessed by echocardiography, haemodynamic parameters by cardiac catheterization, histopathological changes by light and electron microscopy and cardiomyocyte apoptosis by TUNEL. Caspase-3, Bcl-2, bax, calpain I, calpastatin, matrix metalloproteinase (MMP)-9 and tissue inhibitors of metalloproteinase (TIMP)-1 were analysed by immunohistochemistry and Western blotting. The inducibility and duration of AF were measured by atrial burst pacing.

Key results:

After atrial pacing, the proportion of TUNEL positive cells, myolysis, atrial fibrosis and dilatation were all significantly increased and these changes were inhibited by spironolactone. Spironolactone treatment reversed the increased expression of caspase-3, bax, calpain I and MMP-9 and the decreased level of Bcl-2, calpastatin and TIMP-1, induced by chronic atrial pacing. Also spironolactone prevented the increased inducibility and duration of AF, induced by tachypacing.

Conclusions and implications:

Treatment with spironolactone prevented myocardial apoptosis, myolysis, atrial fibrosis and dilatation, suggesting a possible beneficial effect of aldosterone antagonism on atrial structural remodelling in AF.This article is commented on by Lendeckel et al., pp. 1581–1583 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2010.00675.x     

心房颤动患者右心房肌闰盘重构的研究

目的：探讨心房颤动（房颤）患者右心房肌细胞间闰盘相关蛋白表达变化与房颤发生并维持的意义。方法：心外科患者53例，其中房颤患者27例（房颤组），窦性心律患者26例（窦律组），在建立体外循：吓前取右心房组织。分别将心房组织提取mRNA和制作病理组织切片，部分组织送电镜检查。用RT—PCR方法检查Cx40、Cx43mRNA表达变化，用免疫组化方法检测Cx43、N-钙黏素的分布变化。结果：两组患者Cx40、Cx43mRNA表达无变化，免疫组化结果显示房颤组缝隙连接、N-钙黏素分布发生不均一，光镜、电镜证实房颤组缝隙连接发生侧边化分布明显。结论：闰盘相关蛋白表达改变在房颤的维持中发挥重要作用。     

Electropharmacologic effects of pilsicainide, a pure sodium channel blocker, on the remodeled atrium subjected to chronic rapid pacing.

Clinical experience suggests that sodium channel blockers are effective in converting atrial fibrillation of recent onset but not chronic atrial fibrillation. We investigated changes in the electrophysiologic effects of pilsicainide, a pure sodium channel blocker, on the canine atrium during chronic rapid pacing (400/min). Three pairs of bipolar electrodes were sutured to the right atrial appendage in six dogs. Five days later, rapid atrial pacing was started after baseline measurements of the effective refractory period (ERP), the intra-atrial conduction velocity, the atrial wavelength, and the inducibility of atrial fibrillation. These studies were repeated at 2, 7, and 14 days of pacing, both before and after pilsicainide administration. Before pacing, pilsicainide increased ERP more than it decreased conduction velocity, causing an increase of wavelength, particularly at faster rates. However, this use-dependent prolongation of ERP disappeared after 2 days of pacing. Thus, pilsicainide failed to prolong ERP during chronic pacing, allowing progressive shortening of wavelength in the remodeled atrium. The effect of sodium channel blockers on atrial refractoriness may decline as rapid atrial excitation persists, limiting the usefulness of these agents for the treatment of chronic atrial fibrillation.     

慢性心房颤动犬心房组织肾素-血管紧张素系统的表达及意义

目的探讨肾素-血管紧张素系统(RAS)在慢性心房颤动犬心房组织中的表达及意义。方法健康杂种犬16条,随机分为正常对照组8条,单纯心房颤动起搏组8条。心房颤动组植入埋藏式高频率心脏起博器(500±20)次/min,起博24周后处死动物,分别于左、右心房取材,采用免疫组织化学检测心房组织中肾素-血管紧张素转化酶(ACE)、血管紧张素Ⅱ1型受体(AT1R)以及肾素-血管紧张素转化酶抑制剂(ACEI)的表达变化。正常对照组未植入起搏器,与心房颤动组同步行相应检查。结果与对照组比较,心房颤动组心房组织中ACE和AT1R表达水平显著增强,而ACEI的表达水平明显下降,各组间比较差异有统计学意义(P<0.01)。结论慢性心房颤动犬心房组织RAS的激活参与了心房颤动的形成,可能是心房颤动发生、发展的主要机制之一。     

阵发性房颤诱发大鼠心房肌电重构特征研究

目的:探讨氯化钙-乙酰胆碱混合液引起的房颤大鼠心房电重构特征。方法:雄性SD大鼠,随机分为正常组和模型组,每组20只。CaCl210mg/mL+ACh 66μg/mL混合液尾静脉注射诱发大鼠房颤,连续诱发7d,正常组静脉注射生理盐水7d。心电图监测大鼠房颤持续时间、心房复极相关心电图参数变化。7d后,观察正常和房颤大鼠心房肌有效不应期,Western-blot法测定心房肌通道蛋白Kv 1.5、Kv 4.2/4.3,钙稳蛋白FKBP 12.6和缝隙连接蛋白Cx40的表达。结果:Ach-CaCl2连续静脉注射引起大鼠房颤持续时间逐渐延长,与正常组相比,房颤大鼠P波变宽,Pd增大,心房有效不应期缩短(P<0.01),同时心房肌Kv 1.5、Kv 4.2/4.3表达下降,FKBP12.6减少,Cx40含量下降(P<0.05)。结论:氯化钙-乙酰胆碱混合液持续给予7d,大鼠心房发生电重构,特征符合或接近临床房颤基质电重构特征。