5-HT_(2B)受体阻断剂对心肌肥厚大鼠心肌5-HT含量及5-HT_(2B)受体表达的影响

目的观察5-HT2B受体阻断剂对去甲肾上腺素(norepinephrine,NE)诱导的心肌肥厚大鼠心肌中5-羟色胺(5-hydrotriptamine,5-HT)含量及5-HT2B受体表达的影响。方法雄性SD大鼠24只,随机分为3组,8只/组,分别为对照组、肥厚组、实验组。采用腹腔注射NE(1.5 mg/kg,2次/d,28 d)的方法建立心肌肥厚模型,自第15天起实验组腹腔注射SB204741(5-HT2B受体阻断剂;2 mg/kg,2次/d),连续注射14 d。对照组腹腔注射相同体积的生理盐水(2次/d,28 d)。检测各组左心室重量与体重之比(LVW/BW)、心肌组织中5-HT的含量及5-HT2B受体的表达情况。结果在NE诱导心肌肥厚过程中,应用SB204741干预可显著减轻心肌肥厚的程度,降低心肌组织中5-HT的含量,并抑制5-HT2B受体表达的上调。结论应用5-HT2B受体阻断剂可减轻NE诱导心肌肥厚的程度,降低心肌组织中5-HT的含量,并抑制5-HT2B受体表达的上调。     

5-HT_(2B)受体阻断剂对去甲肾上腺素诱导的肥厚心肌组织中心肌细胞凋亡的影响

目的观察5-HT2B受体阻断剂对去甲肾上腺素(NE)诱导的肥厚心肌组织中心肌细胞凋亡的影响。方法雄性SD大鼠24只,随机分为3组,每组8只,分别为对照组,肥厚组、实验组。采用腹腔注射NE(1.5 mg/kg,2次/d,28 d)的方法建立心肌肥厚动物模型,自第15天起实验组腹腔注射SB204741(5-HT2B受体阻断剂)2 mg/kg,2次/d,连续注射14 d。对照组腹腔注射相同体积的生理盐水2次/d,28 d。采用TUNEL法检测各组心肌组织中心肌细胞的凋亡情况,Western blot方法分析Bcl-2、Bax、Caspase-3的表达情况。结果对照组的心肌组织中几乎看不到凋亡的心肌细胞,肥厚组心肌组织中凋亡心肌细胞数量显著增多,同时Bcl-2/Bax表达比例显著降低,Caspase-3的表达显著升高;与肥厚组相比,实验组心肌组织中凋亡心肌细胞的数量显著减少,Bcl-2/Bax表达比例显著升高,Caspase-3的表达显著降低。结论应用5-HT2B受体阻断剂不仅可减轻NE诱导的心肌肥厚的程度,还可通过上调Bcl-2/Bax表达比率、降低Caspase-3的活性抑制心肌细胞的凋亡。     

5-羟色胺对去甲肾上腺素诱导大鼠心肌肥厚的影响

目的　了解 5 羟色胺 (5 HT)对去甲肾上腺素(NE)所致心肌肥厚有何影响。方法　大鼠分别ip5 HT 2mg·kg- 1,NE 2mg·kg- 1或NE 2mg·kg- 1+ 5 HT 2mg·kg- 1。每日 2次 ,连续给药 15d ,d 16麻醉 ,颈动脉插管 ,观察累积iv不同剂量 5 HT对平均动脉压和心电图的影响 ,之后处死大鼠 ,观察心重与体重之比。结果　累积iv 5 HT ,NE组和NE + 5 HT组大鼠血压明显升高 ,诱发室速和室颤的鼠数明显增加 ,但该两组间无显著差异。NE组心室重与体重之比明显增加 ,NE + 5 HT组较NE组相比进一步增加。结论　 5 HT加强NE诱发大鼠心肌肥厚和心律失常的作用。     

维拉帕米对去甲肾上腺素诱导的培养大鼠心肌细胞β受体下调的影响

目的：研究维拉帕米（Ｖｅｒ）是否能抑制去甲能上腺素（ＮＥ）诱导的培养大鼠心肌细胞β受体下调配可能机制。方法：β受体密度用［＾３Ｈ］－ＤＮＡ放射配基标记法，细胞内游离钙用钙离子荧光探针Ｆｕｒａ２－ＡＭ法测定。结果：Ｖｅｒ以明显降低培养大鼠心肌细胞内游离钙水平，增加β受体密度；ＮＥ增加细胞内游离钙水平，降低β受体密度；Ｖｅｒ能明显抑制ＮＥ引起的细胞内游离钙增加和β受体密度的降低。结论：Ｖｅｒ能增加正常     

miR-21在异丙基肾上腺素诱导的心肌肥厚中的作用

背景及目的：心肌肥厚是心肌对各种原因导致的血流动力学超负荷做出的适应性反应，是多种心血管疾病的共同归宿，如不能得到有效控制，将最终发展为心力衰竭。迄今为止，心肌肥厚和心力衰竭的治疗仍是一个难点。随着对心肌肥厚发病机制的不断深入的研究，基因表达的转录后调节在心肌肥厚进程中的作用越来越受到人们的重视。MicroRNA（miRNA）是一类非编码RNA，主要参与基因表达的转录后调节     

β-受体阻断剂对异丙肾上腺素提高心肌耗氧量作用的影响

本文用心肌薄切片观察β_1受体阻断剂氯甲苯心安(Bupranolol)和ACC-9089对异丙肾上腺素兴奋β_1受体提高心肌耗氧量的阻断拮抗作用。氯甲苯心安由辽宁省药物研究合成,ACC-9089是美国医院供应合作急症分部合成。它们的结构式为:     

FDA批准经皮吸收5-HT_3受体阻断剂Sancuso上市

2008年9月15日，苏格兰ProStrakan制药公司宣布FDA批准第一个经皮吸收的5-HT3受体抑制剂Sancuso上市，用于治疗化学疗法诱发的恶心和呕吐（CINV）。Sancuso通过一种粘着剂固定于上臂皮肤，缓慢持续释放止吐药物成分格拉司琼（Granisetron），可保持有效血药浓度长达5d。     

茶多酚对异丙肾上腺素致大鼠心肌肥厚的保护作用

目的观察茶多酚对大鼠心肌肥厚的保护作用并讨论其相关可能作用机制。方法采用皮下注射异丙肾上腺素（ISO）建立大鼠心肌肥厚模型,将28只SD大鼠随机分为对照组、模型组、美托洛尔组、茶多酚组,灌胃给药连续14d后,取心脏称重后计算全心重量指数及左心重量参数;分别检测测定心肌组织一氧化氮合酶（NOS）活性及心肌组织血管紧张素Ⅱ（AngⅡ）及钙调神经磷酸酶（CaN）的水平。结果与模型组相比,茶多酚能显著改善心脏质量指数,心肌组织NOS活性显著升高、AngⅡ含量降低、CaN活性明显降低。结论茶多酚对异丙肾上腺素所致大鼠心肌肥厚具有保护作用,其作用机制可能与提高NO水平、降低CaN活性、抑制AngⅡ有关。     

κ受体激动对去甲肾上腺素诱导的心肌肥大的抑制作用

目的　利用体外培养的乳鼠心肌细胞 ,观测κ阿片肽受体激动对去甲肾上腺素 (norepinephrine ,NE)诱导的心肌肥大的抑制作用 ,并探讨作用机制。方法　对培养乳鼠心肌细胞分组给药 48h后 ,用Lowrys法测心肌细胞的蛋白质含量 ;用消化分离法 ,通过目镜标尺测心肌细胞体积 ;用镜下计数法测心肌细胞的搏动频率。结果　κ阿片肽受体激动剂U5 0 ,488H(简称U5 0 ) (0 1～ 10 μmol·L-1)对培养心肌细胞的蛋白质含量具有抑制作用并呈剂量依赖性 ;对NE诱导的心肌细胞蛋白含量增加、体积增大具有抑制作用 ;同时观察到U5 0 ,488H(1μmol·L-1)具有抑制心肌细胞搏动频率的作用。U5 0 ,488H的上述作用均可被κ阿片肽受体拮抗剂Nor BNI(1μmol·L-1)拮抗。结论　U5 0 ,488H对NE诱导的心肌肥大具有抑制作用 ,这种作用是通过激动κ阿片肽受体发挥的。     

5-HT_(2C)受体的螺旋结构与功能

5-羟色胺(5-HT)是动物中枢神经和外周神经系统中重要的递质〔1〕,在人的中枢神经系统中调节人体的许多活动;在非神经组织中,5-HT也同样起重要作用。迄今为止,在人类的中枢神经系统已经发现了14种5-HT受体亚型,即5-HT1A,5-HT1B,5-HT1D,52HT1E,5-HT1F,5-HT2A,5-HT2B,5-HT2C,5-HT3     

Effects of crocetin on the matrix metalloproteinases in cardiac hypertrophy induced by norepinephrine in rats

The effects of crocetin on the cardiac hypertrophy induced by long-term treatment with norepinephrine (NE) in rats have been investigated. The activities of matrix metalloproteinases (MMP-2 and MMP-9) have been assayed by gelatin SDS-PAGE zymography. The expressions of MMP-2 and MMP-9 were detected by RT-PCR. ATPase activity and hydroxyproline contents were measured with a commercial kit. The results show that crocetin blocked the development of left ventricular hypertrophy induced by NE, decreased the level of collagen in myocardium, enhanced both the Na⁺-K⁺ ATPase activity in cardiac tissue and the Ca²⁺-Mg²⁺ ATPase activity in mitochondria and inhibited significantly the activity of MMP-2 and the expressions of MMP-2 and MMP-9. These results suggest that crocetin may prevent cardiac hypertrophy induced by NE in rats.     

[3H]Rauwolscine: an antagonist radioligand for the cloned human 5-hydroxytryptamine2B (5-HT2B) receptor

In previous reports, [³H]5-HT has been used to characterize the pharmacology of the rat and human 5-HT_2B receptors. 5-HT, the native agonist for the 5-HT_2B receptor, has a limitation in its usefulness as a radioligand since it is difficult to study the agonist low-affinity state of a G protein-coupled receptor using an agonist radioligand. When using [³H]5-HT as a radioligand, rauwolscine was determined to have relatively high affinity for the human receptor (K_i human = 14.3 ± 1.2 nM, compared to K_i rat = 35.8 ± 3.8 nM). Since no known high affinity antagonist was available as a radioligand, these studies were performed to characterize [³H]rauwolscine as a radioligand for the cloned human 5-HT_2B receptor expressed in AV12 cells. When [³H]rauwolscine was initially tested for its usefulness as a radioligand, complex competition curves were obtained. After testing several α₂-adrenergic ligands, it was determined that there was a component of [³H]rauwolscine binding in the AV12 cell that was due to the presence of an endogenous α₂-adrenergic receptor. The α₂-adrenergic ligand efaroxan was found to block [³H]rauwolscine binding to the α₂-adrenergic receptor without significantly affecting binding to the 5-HT_2B receptor and was therefore included in all subsequent studies. In saturation studies at 37° C, [³H]rauwolscine labeled a single population of binding sites, K_d = 3.75 ± 0.23 nM. In simultaneous experiments using identical tissue samples, [³H]rauwolscine labeled 783 ± 10 fmol of 5-HT_2B receptors/mg of protein, as compared to 733 ± 14 fmol of 5-HT_2B receptors/mg of protein for [³H]5-HT binding. At 0° C, where the conditions for [³H]5-HT binding should label mostly the agonist high affinity state of the human 5-HT_2B receptor, [³H]rauwolscine (B_max = 951 ± 136 fmol/ mg), again labeled significantly more receptors than [³H]5-HT (B_max = 615 ± 34 fmol/mg). The affinity of [³H]rauwolscine for the human 5-HT_2B receptor at 0° C did not change, K_d = 4.93 ± 1.27 nM, while that for [³H]5-HT increased greatly (K_d at 37° C = 7.76 ± 1.06 nM; K_d at 0° C = 0.0735 ± 0.0081 nM). When using [³H]rauwolscine as the radioligand, competition curves for antagonist structures modeled to a single binding site, while agonist competition typically resulted in curves that best fit a two site binding model. In addition, many of the compounds with antagonist structures displayed higher affinity for the 5-HT_2B receptor when [³H]rauwolscine was the radioligand. Typically, ∼ 85% of [³H]rauwolscine binding was specific binding. These studies display the usefulness of [³H]rauwolscine as an antagonist radioligand for the cloned human 5-HT_2B receptor. This should provide a good tool for the study of both the agonist high- and low-affinity states of the human cloned 5-HT_2B receptor. Received: 26 June 1997 / Accepted: 30 August 1997     

5-HT_4受体激动剂兼5-HT_3受体阻断剂2-[1-(4-piperonyl)piperazinyl]-benzothiazole致心律失常机制探析

目的观察5-HT4受体激动剂兼5-HT3受体阻断剂2-[1-(4-piperonyl)piperazinyl]benzothiazole对大鼠离体心脏心律的影响,并探析其电生理学机制。方法采用成年健康SD大鼠建立离体心脏Langendorff主动脉逆行灌流系统,观察0.1～10μmol·L-12-[1-(4-piperonyl)piperazinyl]benzothiazole对离体心脏节律的影响,全程记录心电图的变化。应用全细胞膜片钳技术观察2-[1-(4-piperonyl)piperazinyl]benzothiazole对胶原酶分解的大鼠心室肌细胞膜内向整流钾电流(IK1)、瞬时外向钾电流(Ito)、静息膜电位(RMP)及动作电位(AP)的影响。结果在大鼠离体心脏,0.1～10μmol·L-12-[1-(4-piperonyl)piperazinyl]benzothiazole可诱发明显的心律失常。给药15min内,药物(10μmol.L-1)诱发期前收缩(PVB)236±37个,室速(VT)和室颤(VF)发生率分别达到87.5%和62.5%(n=8,P<0.01)。膜片钳记录结果显示,0.1～10μmol·L-12-[1-(4-piperonyl)piperazi-nyl]benzothiazole可浓度依赖性抑制大鼠心室肌IK1(EC50=0.74μmol·L-1)和Ito(EC50=2.16μmol·L-1),降低膜电位,并明显延长动作电位时程(n=6,P<0.01)。结论作为5-HT4受体激动剂和5-HT3受体阻断剂2-[1-(4-pipero-nyl)piperazinyl]benzothiazole致大鼠心律失常风险的电生理学机制为抑制IK1和Ito,降低膜电位,延长动作电位时程。     

GRK2 and GRK5 as therapeutic targets and their role in maladaptive and pathological cardiac hypertrophy

Introduction: One in every four deaths in the United States is attributed to cardiovascular disease, hence the development and employment of novel and effective therapeutics are necessary to improve the quality of life and survival of affected patient. Pathological hypertrophy is a maladaptive response by the heart to relieve wall stress that could result from cardiovascular disease. Maladaptive hypertrophy can lead to further disease progression and complications such as heart failure; hence, efforts to target hypertrophy to prevent and treat further morbidity and mortality are necessary.

Areas covered: This review summarizes the compelling literature that describes the mechanistic role of GRK2 and GRK5 in maladaptive cardiac hypertrophy; it examines the approaches to inhibit these kinases in hypertrophic animal models and furthermore, it assesses the potential of GRK2 and GRK5 as therapeutic targets for hypertrophy.

Expert opinion: GRK2 and GRK5 are novel therapeutic targets for pathological hypertrophy and may have added benefits of ameliorating morbidity and mortality. Despite the lesser researched role of GRK2 in cardiac hypertrophy, it may be the advantageous strategy for treating cardiac hypertrophy because of its role in other maladaptive pathways. Anti-GRK2 therapy optimization and the discovery and development of specific GRK2 and GRK5 small-molecule inhibitors is necessary for the eventual application of successful, effective therapeutics.     

盐酸沙格雷酯对血管系统作用的研究进展

盐酸沙格雷酯(sarpogrelate hydrochloride,安步乐克)是新上市的5-HT 2 受体阻滞剂,其可能通过维持血管内皮细胞完整、防止血管平滑肌细胞增殖等对血管相关疾病具有重要作用.综述近几年来安步乐克对血管系统作用方面的研究,并讨论其作用特点及可能的作用机制.     

5-HT_(2A)受体基因1438A/G多态性与海洛因依赖的关系

目的··:探讨5 -HT2A 受体基因多态性与海洛因依赖易感性的关系。方法··:用聚合酶链式反应 (PCR)技术结合限制性片段长度多态性 (RFLP)分析技术 ,检测了99名海洛因依赖者和80名正常对照者5 -HT2A 受体基因1438A/G多态性的基因型和等位基因频率。结果··:海洛因依赖者5 -HT2A 受体基因1438A/G多态性基因型A1/A2的频率较对照组高。结论··:5 -HT2A 受体基因1438A/G多态性可能与海洛因依赖的易感性有关     

2型糖尿病大鼠心肌肥厚模型建立及维生素D的干预研究

目的 建立糖尿病大鼠心肌肥厚模型,观察维生素D对2型糖尿病大鼠心肌肥厚干预作用并分析其机制.方法 将采用链脲佐菌素(STZ)腹腔注射建立糖尿病模型成功后并经超声检查确认存在心肌肥厚的19只雄性Wistar大鼠随机分为糖尿病心肌肥厚组(7只)、胰岛素干预组(6只)、维生素D干预组(6只),6只健康Wistar大鼠作为正常对照组.胰岛素组皮下注射常规胰岛素25 U/kg 1次/d,持续28 d;维生素D组给予1,25-(OH)2D32 μg/(kg·d)灌胃,持续28 d.每周检测各组大鼠空腹血糖及胰岛素水平;全部动物于4周后处死,测定左心室质量指数、心肌胶原含量、心肌胶原容积分数,并用蛋白质印迹法检测维生素D受体表达情况.结果 与正常对照组比较,糖尿病心肌肥厚组大鼠胰岛素水平明显降低[(3.8±1.3) mU/L比(24.4 ±2.5)mU/L] (P ＜0.05),空腹血糖,左心室质量指数、心肌胶原含量、心肌胶原容积分数及维生素D受体均明显增加[(28.7±0.5)mmol/L比(4.8±1.1) mmol/L,(2.40±0.46) mg/g比(1.92±0.25) mg/g,(1.93±0.42)mg/g比(1.02±0.28)mg/g,(6.51±1.28)％比(2.64±0.63)％,0.51(VDR/GAPDH比值)比0.24] (P ＜0.05);与糖尿病心肌肥厚组比较,胰岛素干预组或维生素D干预组胰岛素浓度明显升高,余各项指标明显降低(P＜0.05).结论 维生素D对2型糖尿病大鼠心肌肥厚有一定逆转作用,其机制可能与调节血糖水平、刺激胰岛素分泌间接作用,和/或通过其受体对肥厚心肌直接作用有关.     

Corticosterone responses in 5-HT1B receptor knockout mice to stress or 5-HT1A receptor activation are normal

RATIONALE: Previous research found no adaptations in presynaptic 5-HT1A receptors in mice lacking 5-HT1B receptors (5-HT1B KO). Stress and 5-HT1A receptor agonists induce corticosterone release in mice via hypothalamus-pituitary-adrenal (HPA) axis activation. 5-HT1B KO mice are hyperreactive to mild stressors and this might be reflected in altered postsynaptic 5-HT1A receptor sensitivity. OBJECTIVES: Our aim was to determine whether the activity of the HPA axis was increased in 5-HT1B KO mice in response to mild stress and pharmacological activation of 5-HT1A receptors as an indication of putative adaptive changes in postsynaptic 5-HT1A receptor function. METHODS: The effect of mild stress [i.e., the stress-induced hyperthermia (SIH) paradigm], induced by rectal temperature measurement, was determined on temperature and corticosterone over time (0, 5, 10, 20, 30, 60, and 90 min) in 5-HT1B KO and wildtype mice. In addition, corticosterone was measured 60 min after 5-HT1A receptor activation by flesinoxan (0, 0.03, 0.1, 0.3, 1, and 3 mg/kg s.c.). Blood was collected and plasma corticosterone levels were determined by radioimmunoassay. RESULTS: Both genotypes showed comparable time-dependent SIH responses, whereas basal temperature was higher in 5-HT1B KO mice. The effect of SIH on temperature was mirrored by mild increases in plasma corticosterone. Activation of 5-HT1A receptors caused a strong dose-dependent release of corticosterone in both genotypes. Neither response observed showed differences between both genotypes. CONCLUSIONS: Although 5-HT1B KO mice are hyperreactive to mild stress, this reactivity is not reflected by stronger corticosterone responses in the SIH paradigm. The lack of shift in dose-response curves for flesinoxan suggests that postsynaptic 5-HT1A receptor function is unaffected in 5-HT1B KO mice.