枸橼酸乙胺嗪对离体豚鼠胸主动脉环的影响

本工作观察了抗丝虫药枸橼酸乙胺嗪（ＤＥＣ）对离体豚鼠胸主动脉环收缩功能的影响。结果显示，ＤＥＣ能显著抑制ＫＣｌ和去甲肾上腺素（ＮＥ）引起的胸主动脉环收缩．使ＫＣｌ和ＮＥ引起的动脉环收缩的剂量效应曲线右移，最大效应降低，均表现为非竞争性拮抗，其ｐＤ＇２值分别为１．９９１和２．２７１。对收缩机制影响研究发现，ＤＥＣ对细胞内Ｃａ２＋释放和外Ｃａ２＋内流均有明显抑制作用。提示ＤＥＣ可能通过其钙拮抗作用影响血管的收缩。     

双氢杨梅树皮素对兔胸主动脉条平滑肌收缩反应的影响

用兔胸主动脉条研究双氢杨梅树皮素对去甲肾上腺素，ＫＣｌ和ＣａＣｌ２所致兔胸主动脉条收缩反应量效曲线的影响。双氢杨梅树皮素能显著地抑制ＮＥ，ＫＣｌ和ＣａＣｌ２所致兔胸主动脉条的收缩，量效曲线右移，最大反应降低，对高Ｋ＾＋兔胸动脉条收缩的抑制作用明显大于ＮＥ所致兔胸主动脉条收缩的抑制作用。     

间硝地平和硝苯地平对离体人子宫动脉环的比较性研究

用离体人子宫动脉环来研究间硝地平（ｍ－Ｎｉｆ）和硝苯地平（Ｎｉｆ）的作用：ｍ－Ｎｉｆ和Ｎｉｆ能抑制ＫＣｌ所致的收缩，使其量－效曲线右移，最大反应降低，ＰＤ２’分别为７．８±０．５，７．６±０．７，在无钙液中ＫＣｌ几乎不引起收缩反应，两药抑制ＫＣｌ收缩的效应无明显差别；两药亦能使ＮＥ量－效曲线右移，最大反应降低，ＰＤ２’分别为５．５２±０．１１，４．９８±０．３２，在无钙液中ＮＥ的收缩反应降低为４１％±９．２％，ｍ－Ｎｉｆ抑制ＮＥ收缩作用强于Ｎｉｆ。在离体人子宫动脉环，ｍ－Ｎｉｆ和Ｎｉｆ抑制ＫＣｌ收缩作用远强于抑制ＮＥ收缩作用。     

尼莫地平,非洛地平和维拉帕米对离体人血管作用

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ＣａＣｌ２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对无Ｃａ＾２＾＋ｙｍ Ｋ＾＋去极化时ＣａＣｌ２所致离体人血管收缩的拮抗作起收缩时，Ｎｉｍ，Ｆｅｌ和Ｖｅｒ拮抗作用ｐＤ２在子宫动脉分别为７．３８，７．６５和７．２０；在     

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     

多塞平对离体兔基底动脉环和隐动脉环的作用

目的：观察多塞平（ｄｏｘｅｐｉｎ，Ｄｏｘ）对兔脑血管的作用．方法：采用离体兔基底动脉和隐动脉动脉环离体实验方法．结果：多塞平抑制ＫＣｌ４５．６ｍｍｏｌ·Ｌ－１和５羟色胺１０μｍｏｌ·Ｌ－１诱发的兔基底动脉环和隐动脉环收缩，其拮抗ＣａＣｌ２量效反应的ｐＤ２值分别为５．２８±０．４０和４．７６±０．１４（ｎ＝６，Ｐ＜００１）．多塞平５．８μｍｏｌ·Ｌ－１抑制在无Ｃａ２＋液中去甲肾上腺素引起的隐动脉环收缩，多塞平３０μｍｏｌ·Ｌ－１对无Ｃａ２＋液中去甲肾上腺素和恢复正常Ｃａ２＋液（１．２５ｍｍｏｌ·Ｌ－１）引起的隐动脉环收缩均有抑制作用．结论：与隐动脉环相比较，多塞平对基底动脉环具有选择性抑制作用     

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。     

川芎嗪对离体兔血管平滑肌和豚鼠盲肠带的作用

目的：研究川芎嗪对离体兔血管平滑肌和豚鼠盲肠带的作用。方法：制备兔基底动脉环ＫＣｌ量－效曲线、ＣａＣｌ２致盲肠带收缩及兔门静脉条的自律性收缩。结果：川芎嗪非竞争性拮抗ＫＣｌ对兔基底动脉的收缩作用，其ＩＣ５０值为１．５１ｍｍｏｌ／Ｌ，抑制ＣａＣｌ２引起豚鼠盲肠带收缩的ＩＣ５０值为１９０μｍｏｌ／Ｌ，对兔门静脉条收缩也有抑制作用。结论：川芎嗪有钙通道阻滞作用。     

瓜萎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０交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     

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、ＫＣｌ及ＣａＣｌ２收缩兔胸主动脉条的最新曲线呈非竞争性拮抗作用，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。提示大剂量脉强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。     

Effects of l-tetrahydropalmatine on isolated rabbit arterial strips

The effects of l-tetrahydropalmatine (THP) on isolated rabbit aortic, renal and superior mesenteric arterial strips were studied in comparison with verapamil (Ver). THP and Ver shifted the KCl, CaCl2, norepinephrine (NE) and 15-methyl prostaglandin F2 alpha dose-response curves to the right in a non-parallel fashion, and decreased the maximal response, showing noncompetitive antagonism. THP was less potent in dilating arterial strips than Ver. THP and Ver obviously inhibited the intracellular Ca2+-dependent component of NE-induced contraction of the aorta, but only slightly decreased the extracellular Ca2+-dependent component when the concentration of THP or Ver was very high (THP 0.1 mmol/L, Ver 10 mumol/L). The results suggest that THP, similar to Ver, mainly inhibits potential-operated calcium channels. THP and Ver were more potent in dilating renal and superior mesenteric arterial strips than aortic strips. The results indicate that the vasodilation effect of THP is similar to that of Ver and that THP probably has a calcium antagonistic effect.     

哇巴因对豚鼠主动脉环平滑肌作用及与Ca2+、去甲肾上腺素的相互关系

目的观察哇巴因（ouabain,Oua）对豚鼠血管平滑肌的作用，及其与Ca₂₊和去甲肾上腺素（NE）的相互作用关系。方法利用豚鼠离体胸主动脉环，观察药物对其张力的影响。结果无论有无内皮存在，Oua均能剂量依赖性地直接收缩血管平滑肌。在无钙溶液中，Oua不能引起血管收缩。Oua可使ＮＥ的量效曲线平行左移，E_max不变；Oua可使CaCl₂的量效曲线左移上移，E_max增大。硝苯地平和维拉帕米可使Ｏua所致的血管收缩曲线下降。结论Oua所致的血管收缩作用不依赖于血管内皮的存在，但依赖于细胞外钙，并且能被钙拮抗剂所拮抗；NE与Oua，Ca₂₊对血管平滑肌的收缩呈协同作用。     

Comparative cardiovascular actions of clentiazem, diltiazem, verapamil, nifedipine, and nimodipine in isolated rabbit tissues.

Clentiazem is an 8-chloro-substituted derivative of diltiazem. We compared the relative potency of clentiazem with that of diltiazem, verapamil, nifedipine, and nimodipine in isolated rabbit right atria and vascular smooth muscle removed from various arterial beds. In experiments with isolated right atria, calcium channel blockers were added cumulatively to study relative cardiodepressive potencies (as compared with vascular effects) with the following results: verapamil greater than or equal to diltiazem greater than clentiazem greater than or equal to nimodipine much greater than nifedipine. The aorta, pulmonary, renal, mesenteric, coronary, and basilar arteries were removed, cut helically in strips, and mounted in isolated tissue baths to measure isometric force. Vessels were contracted with either 40 mM KCl (opening voltage-operated calcium channels) or 1 x 10(-5) M norepinephrine (NE, opening receptor-operated calcium channels). Cumulative dose-response curves were generated for relaxation with each calcium channel blocker. All compounds were more potent at relaxing potassium-induced contractions than NE-induced contractions. In vessels precontracted with KCl, neither diltiazem, verapamil, or nifedipine showed selectivity for basilar artery as compared with the mesenteric artery. Both clentiazem and nimodipine were selective (6- and 30-fold, respectively) for basilar artery in blocking potassium-induced contractions. When NE was used to contract the arteries, clentiazem (12-fold), diltiazem (8-fold), verapamil (8-fold), and nifedipine (153-fold) were all more potent in relaxing the contraction in basilar artery than in mesenteric artery. Nimodipine failed to demonstrate selectivity for basilar artery as compared with mesenteric artery contracted with NE.(ABSTRACT TRUNCATED AT 250 WORDS)     

Calcium channel blocking activity of calycosin, a major active component of Astragali Radix, on rat aorta

AIM: To investigate the vasoactivity of calycosin, a major active component of Astragali Radix. METHODS: Experiments were performed on isolated rat thoracic aortic rings pre-contracted with phenylephrine (PHE) or KCl. RESULTS: Calycosin produced a concentration-dependent relaxation on the tissue pre-contracted using PHE with 4.46+/-0.13 of pD(2) and 95.85%+/-2.67% of E(max); or using KCl with 4.27+/-0.05 of pD2 and 99.06%+/-2.15% of Emax, and displaced downwards the concentration-response curves of aortic rings to PHE or KCl. The relaxant effect of calycosin on denuded endothelium aortic rings was the same as on intact endothelium aortic rings, and its vasorelaxant effect was not influenced by L-NAME or indomethacin. In Ca(2+)-free solution, calycosin (30 micromol/L) did not have an effect on PHE (1 micromol/L)-induced aortic ring contraction. The effects of calycosin and nifedipine where somewhat different; calycosin decreased aortic ring contractions induced by the two agonists, but nifedipine displayed a more potent inhibitory effect on KCl-induced contractions than on PHE-induced contractions, and the vascular relaxing effects of calycosin and nifidipine were additive on PHE-induced contraction but not KCl-induced. CONCLUSION: Calycosin is a vasorelaxant. Its action is endothelium-independent and is unrelated to intracellular Ca(2+) release. It is a noncompetitive Ca(2+) channel blocker. The effect of calycosin on Ca(2+) channel blockade may be different from that of dihydropyridines. This study demonstrated a novel pharmacological activity of calycosin, and supplied a theoretic foundation for Astragali Radix application.     

Differential vasorelaxant effects of milrinone and amrinone on contractile responses of canine coronary, cerebral, and renal arteries

The vasorelaxant effects of milrinone and amrinone in canine coronary, cerebral, and renal arterial rings or strips contracted by either K+-depolarization, U46619 (a thromboxane mimetic), or prostaglandin F2 alpha (PGF 2 alpha) were quantitated. Milrinone was more potent as a vasorelaxant in coronary arteries relative to cerebral or renal arteries regardless of the mode of contraction; amrinone was coronary selective with K+ contraction only. When comparing potency in arteries contracted by different agonists, milrinone was significantly more potent as a vasorelaxant in all three arteries contracted by either U46619 or PGF2 alpha than in arteries contracted by K+ depolarization, whereas amrinone was only selective for U46619-induced contractions in cerebral arteries. This profile of activity for milrinone was similar to that of sodium nitrite and isoproterenol and dissimilar from the calcium entry blocking agents nimodipine and nifedipine. In conclusion, this study shows that coronary vascular selectivity exists for milrinone and amrinone. Moreover, the relaxant profiles of milrinone and amrinone, with different sources of vascular smooth muscle, are unlike those of calcium entry blocking agents and more similar to the profiles of agents that modulate cyclic nucleotide levels.     

Influence of extracellular Ca2+ on the modulation of alpha-adrenergic-induced contractions in rat aorta.

1. Rat thoracic aortic rings with and without endothelium incubated in a Ca2(+)-free solution showed a significant reduction of the maximal contraction (E max) induced by norepinephrine (NE) and phenylephrine (Ph), while the contraction induced by a 70 mM KCl depolarizing solution was completely abolished. 2. After Ca2+ removal, pD2 values (-log ED50) for NE and Ph were significantly reduced only in vessels without endothelium. 3. Under control conditions, clonidine (C) induced a contraction only in vessels without endothelium; this response was completely abolished by Ca2+ removal and by nifedipine (10(-8) M). 4. Pre-incubation with nifedipine (10(-8) M) produced an effect similar, although less pronounced, than the removal of Ca2+ in vessels with and without endothelium. 5. Nevertheless, aortic rings with intact endothelium showed a greater reduction of E max than rings without endothelium, suggesting that the endothelial layer may act in synergism with calcium channel blockers to inhibit the contractions induced by alpha-adrenergic agonists. 6. The modulation exerted by the endothelium on alpha 1- and alpha 2-adrenergic-induced contractions in rat aortic rings seems to depend both on extracellular Ca2+ concentration and on the release and action of endothelial relaxing factor(s).     

双氢杨梅树皮素对兔胸主动脉条平滑肌收缩反应的影响

用兔胸主动脉条研究双氢杨梅树皮素对去甲肾上腺素（NE）、KCl和CaCl2所致兔胸主动脉条收缩反应量效曲线的影响。双氢杨梅树皮素能显著地抑制NP、KCl和CaCl2所致兔胸主动脉杂的收缩，量效曲线右移，最大反应降低，对高K 所致兔胸主动脉条收缩的抑制作用明显大于NE所致兔胸主动脉条收缩的抑制作用。双氢杨梅树皮素对NE引起的依赖内Ca2 释放的收缩有明显抑制作用，而对NE依赖细胞外Ca2 性收缩区在较高浓度时才显示抑制作用，提示双氢杨梅树皮素可能对电压依赖性钙通道（PDC）有选择性阻滞作用。     

Potentiation by aminoethylisothiourea of the extra-cellular Ca(2+) component of norepinephrine-induced contraction in rat femoral arteries

Aminoethylisothiourea (AET) is a potent inhibitor of inducible nitric oxide synthase (NOS). The present study was performed to investigate whether AET and its rearrangement products might modulate vascular contraction independently of its effects as a NOS inhibitor in rat small femoral arteries. AET caused an endothelium-independent increase in contraction induced by norepinephrine (NE). This effect was not affected by either N(omega)-nitro-L-arginine methyl ester, nitro-L-arginine, indomethacin or propanolol, but it was suppressed in Ca(2+)-free medium. AET enhanced extracellular Ca(2+) component of NE-induced contraction, and this effect was prevented by the receptor-mediated Ca(2+) entry blocker, 1-{beta-[3-(p-methoxyphenyl)-propyloxyl]-p-methoxyphenetyl}- 1H-imidaz ole hydrochloride (SK&F 96365), but not by the voltage-dependent Ca(2+) channel blocker, nitrendipine. AET did not alter the response to CaCl(2) in vessels exposed to KCl depolarization. The protein kinase C (PKC) inhibitor, 2-[1-(3-dimethylaminopropyl)indol-3-yl]-3-(indol-3-yl) (GF 109203X), prevented the potentiating effect of AET on the NE response. AET failed to produce an increase in tone in the presence of NE and GTP in permeabilized arteries. Among the AET rearrangement products, mercaptoethylguanidine produced an endothelium-independent increase in the NE response. 2-aminothiazoline had no effect, and guanidinoethyldisulphide produced relaxation. The effect of mercaptoethylguanidine was dependent on extracellular Ca(+) and was prevented by GF 109203X. These results indicate that AET is able to potentiate the contraction to NE in rat femoral resistance arteries independently of its inhibitory effect on either NOS or cyclo-oxygenase. Its effect occurs via an enhancement of SK&F 96365-sensitive Ca(2+) entry. A PKC inhibitor-sensitive mechanism also appears to be involved in the AET effect. Mercaptoethylguanidine potentiates NE response through a mechanism similar to AET.     

硝苯地平和环匹阿尼酸对易卒中型肾性高血压大鼠血管平滑肌收缩功能的影响

观察了易卒中型肾性高血压大鼠（ＳＰＲＨＲ）主动脉环血管平滑肌在术后血压升高不同阶段收缩反应性．与假手术组相比，随着术后血压的升高，低浓度ＫＣｌ１０～２０μｍｏｌ·Ｌ－１使ＳＰＲＨＲ主动脉环的收缩反应明显增强；苯肾上腺素（Ｐｈｅ）在无钙Ｋｒｅｂｓ液中所致的收缩反应强度降低，而复钙后的收缩张力明显增强；ＳＰＲＨＲ主动脉环在无钙Ｋｒｅｂｓ液中温育１ｈ后，重新复钙后可致收缩反应且为硝苯地平（Ｎｉｆ）所抑制；肌浆网Ｃａ２＋泵抑制剂环匹阿尼酸（ＣＰＡ）在ＳＰＲＨＲ主动脉环上所致的持续收缩反应也明显强于对照并为Ｎｉｆ所阻断；连续给予Ｎｉｆ，卡托普利１８０±１１ｍｇ·ｋｇ－１·ｄ－１８ｗｋ后，ＳＰＲＨＲ的血压均明显下降．在术后１，４ｗｋ，Ｎｉｆ对部分ＳＰＲＨＲ主动脉环在无钙液中复钙所致的收缩反应并无抑制作用且可进一步引起收缩反应．结果表明，肾性高血压大鼠血管平滑肌收缩功能的高反应性与高血压状态下Ｃａ２＋转运的失调有关，不同高血压时期的血管平滑肌细胞膜上的Ｃａ２＋通道特性可能存在差异性．     

The inhibitory action of melatonin on the contractile response to 5-hydroxytryptamine in various isolated vascular smooth muscles

The effects of melatonin on the contractile responses to 5-hydroxytryptamine (5-HT), norepinephrine (NE), angiotensin-1 (AT-1) and potassium were determined on the rabbit isolated aorta, iliac and renal arteries. Melatonin, at 10(-4) or 10(-3) M inhibited the response to 5-HT in the aorta, iliac and renal arteries. Melatonin, at 10(-3) M, had a negligible effect on the responses to NE and AT-1 in all preparations used. The potassium-induced contraction of all 3 preparations used was slightly inhibited by only the high concentration of melatonin (10(-3) M). In a Ca+-free medium with EGTA (0.1 mM), the residual response to 5-HT (10(-5) or 10(-4) M) were inhibited by melatonin (10(-4) or 10(-3) M) in all preparations used. In a Ca2+-free medium with EGTA (0.01 mM), nifedipine (10(-6) M) and 5-HT (5 X 10(-7) M), application of Ca2+ (2 mM) resulted in a tonic contraction, related to receptor operated channels, of all preparations. This Ca2+ dependent, nifedipine insensitive contraction was markedly inhibited or abolished by melatonin at 10(-5) and 10(-4) M. These results demonstrated that melatonin had a generally greater inhibitory effect on the response to 5-HT than those to NE, AT-1 and potassium in vascular smooth muscles. Also the results suggest that action of melatonin on the 5-HT induced contraction is more related to interference with Ca2+ influx through receptor operated channels than release of intracellular Ca2+ from the store site.