新的钙通道阻滞剂 MC9204 对离体兔动脉环的作用

目的：比较ＭＣ９２０４和ｎｉｆｅｄｉｐｉｎｅ（ＮＩＦ）的扩血管强度，并观察ＭＣ９２０４是否具有血管选择性作用。方法：采用离体血管张力实验法，观察ＭＣ９２０４和ＮＩＦ的扩血管作用。结果：ＭＣ９２０４和ＮＩＦ对ＫＣｌ、ＣａＣｌ２和去甲肾上腺素（ＮＥ）引起的离体兔动脉环收缩反应均具有显著的拮抗作用，使剂量－效应曲线右移。在ＮＥ双相收缩实验中，二药均可显著抑制ＮＥ依外Ｃａ２＋性收缩反应，而对ＮＥ依内Ｃａ２＋性收缩反应无抑制作用。结论：ＭＣ９２０４扩血管作用强于ＮＩＦ，ＭＣ９２０４对肾动脉和肠系膜上动脉的抑制作用强于腹主动脉，具有一定的血管选择性作用，此作用通过抑制细胞外Ｃａ２＋的进入而实现。     

三七总皂甙对大鼠颈内动脉、肠系膜前动脉血流动力学的作用比较

三七总皂甙(PNS)30～150mg·kg~(-1)iv使麻醉SD大鼠的MBP.ICAR.MAR下降11％～19％.14％～27％,23％～39％;使MBF增加16％～51％;PMS100.150mg·kg~(-1)使ICBF先增加25％后减少8％～17％.维拉帕米(Ver)150μg·kg~(-1)iv除不使ICBF减小外,也表现出类似效应。表明PNS,Ver对颈内动脉的扩张作用弱于对肠系膜前动脉的扩张作用。具有明显的作用选择性。     

阿托品对兔胸主动脉平滑肌收缩和细胞增殖的影响

用兔胸主动脉条研究Atr,Ver对CaCl₂,Atr对KCI量—效反应的影响。观察到Atr和Ver能抑制2种激动剂所致兔主动脉条的收缩,量一效曲线右移,最大反应降低,其pD₂值分别为4.4和5.8。两药也能明显抑制NE依内Ca²⁺性收缩,Atr对NE依外Ca²⁺性收缩影响较小,说明Atr主要对细胞外Ca²⁺经PDC所致的收缩有抑制作用。在兔ASMC培养中,有Ca²⁺时,Atr抑制ASMC增殖,无Ca²⁺时,Atr 20.6～185.2 μmol/L表现刺激增殖,555.7～1666.7 μmol/L则抑制MSMC增殖,说明Atr对ASMC作用也与Ca(2+)有关。     

淫羊藿甙扩血管作用机制的研究

本实验以离体兔胸主动脉条为标本，对淫羊藿甙（ＥＩ）扩血管作用的机制进行了探讨。ＥＩ２０，４０ｍｇ·Ｌ－１对ＮＥ、ＫＣｌ及ＣａＣｌ２收缩兔主动脉条的量效曲线呈非竞争性拮抗作用；ＥＩ３０ｇ·Ｌ－１能明显抑制ＮＥ诱导的兔主动脉条依赖于细胞外钙的收缩反应，对依赖于细胞内钙的收缩反应没有影响；ＥＩ３０ｇ·Ｌ－１松驰主动脉条的作用与阻断α受体或激动β受体无关。提示ＥＩ的扩血管作用机制可能与其对钙通道的阻滞作用有关。     

蛇床子素对家兔主动脉条的钙拮抗作用

蛇床子素30μmol·L~(-1)及100μmol·L~(-1)使NE、CaCl_2和高K~+除极化所致的家兔主动脉条收缩量—效曲线右移,最大反应降低.表明蛇床子素有松弛血管平滑肌作用,并与Ca~(2+)呈非竞争性拮抗作用.和阻滞α受体或激动β受体无关;选择性作用于电位依赖性Ca~(2+)通道,抑制细胞外Ca~(2+)内流;在100μmol·L~(-1)时,明显减弱NE诱导的依赖细胞内Ca~(2+)收缩。证明蛇床子素松弛血管平滑肌作用可能与其Ca~(2+)拮抗作用有关。     

尼莫地平,非洛地平和维拉帕米对离体人血管作用(英文)

目的:观察尼莫地平(Nim),非洛地平(Fel)是否有不同的作用模式.方法:比较尼莫地平(Nim),非洛地平(Fel)对去甲肾上腺素(NE)和氯化钙(CaCl_2)引起的人动脉收缩的不同作用,并且与维拉帕米(Ver)的作用相比较.结果:Nim,Fel和Ver对无Ca~(2 )高K~ 去极化时CaCl_2所致离体人血管收缩的拮抗作用比其对NE引起收缩拮抗作用强。在CaCl_2引起收缩时,Nim,Fel和Ver拮抗作用pD_2~′在子宫动脉分别为7.50,7.42,6.35;在肠系膜动脉分别为7.38,7.65和7.20;在肾动脉分别为7.87,9.10和7.32,Ver可抑制NE所致的两种收缩成分,Nim或Fel仅抑制外Ca~(2 )内流引起收缩.结论:Fel对肾血管有选择作用.     

Vascular effects of betaxolol, a cardioselective beta-adrenoceptor antagonist, in isolated rat arteries.

The effects of betaxolol on isolated rat arteries and the modes of action were investigated. Betaxolol (10(-5)-10(-3) M) relaxed the 80 mM K(+)-induced contraction of aortic strips concentration-dependently. The 50% inhibitory concentration of betaxolol in the K(+)-induced contraction was 3 times higher than that of papaverine and about 3 times lower than that of bunitrolol. The relaxations by betaxolol were also demonstrated in renal, mesenteric and femoral arteries. Betaxolol (3 x 10(-6) M-10(-4) M) produced rightward parallel shifts of the concentration-response curves for Ca2+ in the K(+)-depolarized aortic strips. On the other hand, betaxolol produced downward shifts as well as rightward shifts of the concentration-response curves for norepinephrine, 5-HT and angiotensin II. In K(+)-depolarized aortic strips, the cytosolic Ca2+ concentration measured with a fluorescent indicator, fura-2, was decreased by betaxolol (10(-4) M) almost concomitantly with the loss of tention. An elevation of external Ca2+ from 2.5 mM to 10 mM restored both the cytosolic Ca2+ concentration and tention. The relaxations of arteries induced by betaxolol were not influenced by glybenclamide, methylene blue, indomethacin or removal of the endothelium. These results suggest that betaxolol possesses a direct vasodilating action, and the action may be due to the inhibition of Ca2+ influx across the cell membrane.     

四氢小檗碱对离体兔主动脉环的作用和离体豚鼠结肠带平滑肌~(45)Ca内流的影响

THB和Ver相似,对KCl和NE所致兔主动脉环收缩,呈非竞争性拮抗,THB的作用弱于Ver。THB对KCl所致的兔主动脉环收缩的松弛作用,能被20 mmol/L CaCl_2所对抗。 THB,THP和Ver明显抑制80 mmol/L KCl所致的豚鼠结肠带平滑肌细胞的~(43)Ca内流。THB的作用与THP相当,但均弱于Ver。     

Effects of felodipine, nitrendipine and W-7 on arterial myosin phosphorylation, actin-myosin interactions and contraction

The relative effects of felodipine, a dihydropyridine with purported calmodulin antagonistic properties, have been compared with the calmodulin inhibitor, W-7, for inhibition of Ca2+-dependent force development and direct inhibition of Ca2+-calmodulin mediated arterial myosin light chain phosphorylation and actin-myosin interactions. Felodipine (IC50 3 X 10(-9) M) was approximately 30 000 X more potent than W-7 (IC50 10(-4) M) and equipotent with another dihydropyridine, nitrendipine, in inhibiting isometric force development in K+-depolarized aortic smooth muscle strips. In contrast, W-7 (IC50 4 X 10(-5) M) was approximately 5 X more potent than felodipine (IC50 2 X 10(-4) M) in inhibiting Ca2+-dependent myosin light chain phosphorylation or superprecipitation of arterial actomyosin. Concentration-related inhibition of both parameters by W-7 was tightly coupled to concomitant inhibition of force development in intact smooth muscle. In contrast, inhibition of myosin light chain phosphorylation and superprecipitation by felodipine was only apparent at concentrations greater than or equal to 10(-5) M while maximal inhibition of force development occurred at a concentration as low as 10(-7) M. Inhibition of contractility by W-7 was minimal in paced rabbit atria, whereas inhibition by felodipine was similar to that seen with nitrendipine. These results suggest that the pharmacologically-relevant mechanism of Ca2+ antagonism in smooth muscle by felodipine is similar to nitrendipine (blockade of the Ca2+ entry channel) and does not involve direct inhibition of Ca2+-calmodulin stimulated myosin light chain phosphorylation and subsequent actin-myosin interactions.     

脉络宁注射液扩血管作用机制的研究

用离体兔胸主动脉条为标本，以维拉帕米（Ｖｅｒ）为对照药，观察了脉络宁注射液对血管平滑肌的作用．结果，脉络宁注射液对ＮＥ、ＫＣＩ及ＣａＣＩ２收缩兔胸主动脉条的量效曲线呈非竟争性拮抗作用，并能明显抑制ＮＥ引起的主动脉条依赖于细胞内钙及细胞外钙的收缩，其作用性质与Ｖｅｒ相似。提示大剂量脉络宁注射液的扩血管作用机制可能与其对钙通道的阻滞作用有关．     

L-四氢巴马汀对离体豚鼠心房的作用

THP和Ver均能对抗CaCl_2所致离体豚鼠右房正性频率作用,非竞争性拮抗CaCl_2左房正性肌力作用以及Iso右房正性频率和左房正性肌力作用。THP和Ver浓度依赖性和频率依赖性地抑制左房收缩中的阶梯现象,使正阶梯翻转为负阶梯。而对休息后加强影响较小。结果提示THP对心房的抑制作用与Ver相似,与拮抗Ca~(2+)有关,可能主要通过抑制心肌细胞外Ca~(2+)内流所致。     

四氢原小檗碱类药物对培养大鼠单个心肌细胞内游离Ca2+的影响

用Fura-2/AM技术和AR-CM-MIC阳离子测定系统,直接测定了四氢小檗碱(tetrahy-droberberine,THB)、左旋四氢巴马汀(l-tetrahydropalmatine,THP)和左旋千金藤立定(l-stepholidine,SPO)对培养大鼠单个心室肌细胞内游离钙([Ca²⁺]i)的影响,并与维拉帕米(Ver)做了比较。结果显示,THB,THP,SPD浓度为10～100μmol·L^-1时,均可使静息[Ca²⁺]i轻度升高,河豚毒素不能抑制之;浓度为1～100μmol·L^-1时,可明显抑制高K+引起的[Ca²⁺]i增高;30μmol·L^-1对胞外高Ca²⁺和去甲肾上腺素引起的[Ca²⁺]i增高也有明显的抑制作用,但均较Ver的抑制作用为弱;THPB对哇巴因引起的[ca²⁺]i升高无明显抑制作用。结果提示,THB,THP,SPD在抑制电压依赖性钙通道从而影响细胞膜[ca²⁺]i内流方面与Ver相似,但比Ver弱。     

对氯苄基四氢小檗碱抑制钙离子引致的血管平滑肌收缩

AIM: To investigate influences of p-chlorobenzyltetrahydroberberine (CPU-86017) and levothyroxin (Lev) on vascular smooth muscle (VSM) contractions by intracellular Ca2+ release and calcium entry. METHODS: Three kinds of contractions of rat thoracic aortic rings were used to compare suppression by CPU-86017, bepridil (Bep), verapamil (Ver), and nimodipine (Nim) in euthyroid- and Lev-induced hyperthyroidism rats. RESULTS: The IC50 of CPU-86017 on KCl-induced contractions of euthyroid and hyperthyroid VSM were 80 (36-179) and 121 (62-236) mumol.L-1, respectively. The potency of CPU-86017 was approximate to 1/10 of Bep and 1/100 of Ver and Nim. Suppressions of Ver and Nim on hyperthyroid VSM in Ca(2+)-free solution were greatly attenuated by -86% and -95%, respectively. Slight or no change in activity of CPU-86017 and Bep was found. Contractions on adding Ca2+ into Ca(2+)-free medium were suppressed by CPU-86017 and its potencies in euthyroid and hyperthyroid rats were not different. CONCLUSION: CPU-86017 is more potent to suppress Ca2+ entry than intracellular calcium mobilization and Lev enhances both.     

Effects of cilostazol, a selective cAMP phosphodiesterase inhibitor on the contraction of vascular smooth muscle

The effects of cilostazol (OPC-13013, 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydro-2(1H)-quin olinone) on cyclic nucleotide metabolism and Ca2+-induced contraction of intact and skinned rabbit arterial smooth muscles were investigated. The concentrations of cilostazol producing 50% inhibition of cyclic adenosine monophosphate phosphodiesterase and Ca2+-dependent cyclic nucleotide phosphodiesterase were 0.4 microM and above 100 microM, respectively. This compound has no significant effect on adenylate cyclase in concentrations of up to 100 microM. Addition of cilostazol increased significantly the cAMP content without significant effect on cyclic guanosine monophosphate level of rabbit thoracic aorta in the presence of forskolin. Moreover, the ED50 value of cilostazol in relaxation of rabbit mesenteric arterial strips was decreased selectively by addition of 0.01 microM forskolin, which alone at this concentration has no effect on vascular contraction. Cilostazol of up to 30 microM did not suppress the Ca2+-induced contraction of the chemically skinned rabbit mesenteric artery. Therefore, cilostazol may produce the relaxation of intact vascular smooth muscle by its inhibition of cyclic adenosine monophosphate hydrolysis.     

Effects of high calcium diet on arterial smooth muscle function and electrolyte balance in mineralocorticoid-salt hypertensive rats.

1. The effects of a high calcium diet (2.5%) on blood pressure, electrolyte balance, plasma and tissue atrial natriuretic peptide (ANP), cytosolic free Ca2+ concentration ([Ca2+]i), and arterial smooth muscle responses were studied in one-kidney deoxycorticosterone (DOC)-NaCl hypertensive Wistar rats. 2. Calcium supplementation for 8 weeks markedly attenuated the development of DOC-NaCl hypertension and the associated cardiac hypertrophy, and prevented the DOC-NaCl-induced sodium-volume retention as judged by reduced plasma Na+, and decreased plasma and ventricular ANP concentrations in high calcium-fed DOC-NaCl rats. However, calcium supplementation did not affect the DOC-NaCl-induced rise in platelet [Ca2+]i. 3. Smooth muscle contractions of isolated mesenteric arterial rings in response to depolarization by K+ (20-30 mM) were enhanced in DOC-NaCl-treated rats, this enhancement being abolished by concurrent oral calcium loading. The Ca2+ entry blocker nifedipine (10 nM) inhibited the contractions induced by K+ (30-125 mM) more effectively in DOC-NaCl rats than in controls, while the inhibition in calcium-loaded DOC-NaCl rats was significantly greater than in controls only with 30 mM K+. 4. The contractions of mesenteric arterial rings induced by omission of K+ from the organ baths were used to evaluate cell membrane permeability to ions. In chemically denervated rings the onset of the gradual rise in contractile force in K(+)-free medium occurred earlier, and the rate of the contraction was faster in DOC-NaCl-treated rats than in controls and high calcium-fed DOC-NaCl rats. Smooth muscle relaxation induced by 0.5 mM K+ upon K(+)-free contractions was clearly slower in DOC-NaCl rats than in controls and calcium-supplemented DOC-NaCl rats. 5. The functions of arterial smooth muscle Na+, Ca2+ exchange and Ca(2+)-ATPase were evaluated by the aortic contractions elicited by low Na+ medium, and the subsequent relaxation responses induced by Ca(2+)-free solution (in the presence of 5 mM caffeine, 1 microM nifedipine and 10 microM phentolamine). The rate of aortic low Na+ contractions (evaluating Ca2+ influx via Na+, Ca2+ exchange), as well as that of subsequent relaxations was slower in DOC-NaCl-treated rats than in controls, whether the relaxation was induced in normal (144.0 mM) or low (1.2 mM) organ bath Na+ concentration (reflecting Ca2+ extrusion by both Ca(2+)-ATPase and Na+, Ca2+ exchange, and by Ca(2+)-ATPase alone, respectively). However, in calcium-supplemented DOC-NaCl rats the aortic responses did not differ from control.(ABSTRACT TRUNCATED AT 400 WORDS)     

瓜蒌提取物对离体家兔胸主动脉条收缩的影响

以兔离体主动脉条为实验材料,观察ＥＦＴ对去甲肾上腺素（ＮＥ）、氯化钾（ＫＣｌ）和氯化钙（ＣａＣｌ２）的剂量－效应曲线的影响及主动脉条的α受体及β受体的作用．观察了ＥＦＴ对ＮＥ引起的兔主动脉条２种收缩成分的影响．结果ＥＦＴ能舒张已被氯化钙、高钾和去甲肾上腺素收缩的兔主动脉条,使ＮＥ、ＫＣｌ、ＣａＣｌ２的剂量－效应曲线非平行右移,最大效应降低．ＥＦＴ松驰血管平滑肌的作用不依赖于阻断α受体或β受体．而与戊脉安（Ｖｅｒ）相似,是通过阻断钙通道实现的．但它们阻断钙通道的方式不同．ＥＦＴ可能无选择性阻断电位依赖性钙通道和受体操纵性钙通道,而Ｖｅｒ则只选择性阻断．因此,ＥＦＴ的扩血管机制与其对钙通道阻断作用有关     

The relationship between calcium and increased sensitivity of rabbit aortae four hours after reserpine.

1 Four hours after reserpine, rabbit aortic strips were supersensitive to acetylcholine, isoprenaline and noradrenaline. The threshold concentration of the drugs necessary to induce a response was less and the maximum tension developed by the tissues was greater than in control strips. 2 Reserpine-treatment potentiated the contractile responses to CaCl2. 3 Reserpine-treatment resulted in an increase in calcium uptake and an increase in the slow component of 45Ca2+ efflux. 4 After resperine-treatment, the rate of relaxation from a potassium-induced contraction was decreased. 5 It is concluded that reserpine-induced supersensitivity is related to an enhanced ability of the tissue to retain and utilize calcium.     

钩藤碱对大鼠离体子宫收缩反应的影响

本文观察到Rhy对催产素和高K~+去极化后Ca~(2+)引起的大鼠离体子宫收缩均有抑制作用,前一作用可被Ca~(2+)所对抗。CaCl_2量效曲线显示,Rhy对其呈非竞争性拮抗。在无Ca~(2+)高K~+液中,Rhy10μM抑制催产素依赖细胞内Ca~(2+)引起的收缩,而Rhy 40μM除加强这一作用外,对催产素依赖细胞外Ca~(2+)的收缩亦有抑制作用。