异黄酮化合物1461扩血管作用的探讨

本文通过离体兔主动脉条实验,证明1461对血管平滑肌有明显的松弛作用。其作用能被心得安减弱。又能使NA效应曲线右移,同样浓度10~(-5)M酚妥拉明、戊脉安及1461,它们的ID_(50)(即50％抑制量)分别为<4.5、5.6及6.58。1461与戊脉安对高K~+去极化所致的收缩有明显的抑制作用,1461(1.6×10~(-3)M与戊脉安(1.6×10~(-4)M)对KC1的阻遏率分别为43.7％及95.1％。在无Ca~(2+)溶液中,1461与戊脉安都能明显对抗外Ca~(2+)的收缩作用,又能使KC1最大反应率明显下降。据此,我们初步认为1461对血管平滑肌的松弛作用与戊脉安相似,但作用较弱。     

盐酸地尔硫革的药理作用及其毒性试验

本文验证了国产盐酸地尔硫(艹卓)的一些心血管药理作用及其急性毒性。它能抑制电刺激引起的离体兔左心房收缩(IC_(50)3.35μM);对去甲肾上腺素引起的离体兔主动脉条收缩,作用很弱,但能浓度依赖性地抑制氯化钾引起的兔主动脉条收缩(IC_(50) 0.21μM)。它能有效地对抗哇巴因所致豚鼠心律失常;降低麻醉大鼠的血压约22mmHg,持续30 min-并使其心率明显减慢。小鼠口服和静脉注射的 LD_(50)值分别为34.3和335.5mg/kg。     

淫羊藿总黄酮对肾上腺素能受体阻断作用的研究

淫羊藿总黄酮（ＴＦＥ，０，１３ｇ·Ｌ－１）抑制兔离体右心房肌的肌力和心率，此作用无Ｍ受体激动效应和钙拮抗作用，能使异丙肾上腺素（ＩＳＯ，１０－７ｍｏｌ·Ｌ－１）对心房肌的正性频率作用的量效曲线平行右移。ＴＦＥ不影响ＩＳＯ（１０－７ｍｏｌ·Ｌ－１）对豚鼠气管条的负性肌力作用和去甲肾上腺素（ＮＥ，１０－６ｍｏｌ·Ｌ－１）对兔主动脉条的正性肌力作用。ＴＦＥ（ｉｖ，１００ｍｇ·ｋｇ－１）明显降低麻醉猫和大鼠血压，减弱ＩＳＯ（１０μｇ·ｋｇ－１）所致的大鼠心率加快的作用，但对ＩＳＯ和肾上腺素（Ａｄｒ）的降压作用无影响，也不增敏Ａｄｒ的升压作用。实验结果证实ＴＦＥ选择性阻断离体及整体动物心肌β１受体，对气管β２受体和血管平滑肌α受体无阻断作用。     

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。     

雌酚酮衍生物EA204对离体兔血管平滑肌的舒张作用

目的探讨雌酚酮衍生物(EA204)对离体兔血管平滑肌的作用及其机制。方法以离体兔主动脉条为标本,观察了EA204对去甲肾上腺素(NE)、氯化钾(KCl)引起的兔主动脉条收缩的影响;对氯化钙(CaCl2)累积收缩量效曲线的影响,并与维拉帕米(Ver)相比较。通过对比格列苯脲(10μmol.L-1)孵育前后EA204对BaCl2、KCl的舒张量效曲线,研究EA204对钾通道的作用。结果EA204(10~3 mmol.L-1)可以剂量依赖性地抑制NE、KCl收缩的兔主动脉条;EA204(10μmol.L-1)或Ver(0.1μmol.L-1)都使CaCl2累积收缩量效曲线呈剂量依赖性右移,但EA204孵育后CaCl2量效曲线最大反应基本不变,而Ver使最大反应降低;加入格列苯脲(10μmol.L-1)孵育后EA204对BaCl2、KCl收缩的主动脉条的舒张量效曲线发生明显变化,EA204的舒张作用被抑制。结论EA204具有舒张离体兔血管平滑肌的作用,其作用机制与其钙通道阻断作用和钾通道开放作用有关。     

酚妥拉明、去氧肾上腺素对兔离体气管平滑肌收缩力的影响

目的 观察酚妥拉明及去氧肾上腺素对离体气管平滑肌张力的影响.方法 观察一定剂量的酚妥拉明、去氧肾上腺素对静息状态下离体兔气管平滑肌张力的影响;用电刺激诱发兔离体气管平滑肌收缩,观察一定剂量的酚妥拉明、去氧肾上腺素对其的影响.结果 酚妥拉明0.66mmol/L圾去氧肾上腺素1.23 mol/L对静息状态气管平滑肌无直接收缩作用(P＞.05).酚妥拉明0.66 mmol/L可显著抑制电刺激诱发的气管平滑肌收缩(P＜0.01).去氧肾上腺素1.23 mmol/L使电刺激兔离体气管平滑肌收缩力略有增加(P＞0.05).结论 酚妥拉明对电刺激诱发兔离体气管平滑肌收缩力有显著的抑制作用;去氧肾上腺素则无明显影响.     

细辛油药理作用研究

细辛油能松驰兔离体主动脉条，使去甲肾上腺素所致主动脉收缩的量效曲线右移并效能降低；使离体兔耳灌流量减少；能延长小鼠常压耐缺氧时间；用其1／2LD50之剂量腹腔注射给药3天，可致小鼠骨髓微核形成增加。     

心脉隆注射液对不同状态大鼠离体胸主动脉的影响

摘 要 目的：探讨心脉隆注射液（XML）对不同状态大鼠离体胸主动脉的影响。方法: 采用累积加药法,观察XML对静息、氯化钾（KCl）或去甲肾上腺素（NA）预收缩大鼠离体胸主动脉的影响。使用不同工具药分析作用产生的机制。结果: 与对照组相比,XML在一定浓度范围内可以兴奋静息离体胸主动脉,进一步增加KCl预收缩血管的张力,而降低NA预收缩血管的张力。XML舒张NA预收缩血管的作用可被普萘洛尔、双氯芬酸所抑制,而不受Nω-硝基-L-精氨酸的影响。结论:XML对不同状态下大鼠离体胸主动脉的作用不同,其机制可能与Ca²+通道、β受体和前列腺素有关。     

薤白提取物对兔离体主动脉条的作用

本实验以离体兔主动脉条为标本 ,对薤白 (EA)的扩血管机制进行了探讨 .观察了薤白对去甲肾上腺素 (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EA对NE引起的兔主动脉条两种收缩成分的影响 .结果表明EA能舒张已为氯化钙、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 .EA松弛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 .EA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 .因此EA的扩血管机制与其对钙通道阻断作用有关 .     

硝苯吡啶对兔输卵管活动和卵子运行的影响

钙道阻断剂硝苯吡啶(NIF)可明显延缓卵子在兔输卵管内的运行速度。在HCG处理的麻醉兔,NIF抑制输卵管的自发收缩,并说明减弱去甲肾上腺素(NA)和15-甲基PGF_2α所致输卵管腔内压升高和电活动增强。在离体兔输卵管环肌标本,NIF能明显压低NA使峡部和壶腹部环肌张力提高的浓度—反应曲线。以上提示NIF延缓兔卵子运行可能与其阻断钙通道,抑制平滑肌收缩和/或降低输卵管平滑肌对内源性NA和PGF_2α的反应性有关。     

Study on adrenergic function after development of tolerance to ethylene glycol dinitrate (EGDN) in rats

The effects of sustained exposure to ethylene glycol dinitrate (EGDN; 50 mg.kg-1.2, 10 days) on heart rate (HR) and mean arterial blood pressure (MAP), isolated strips from aorta and vena cava, catecholamine (CA) and DOPAC levels in brain, heart, adrenals and plasma, and synaptosomal uptake of noradrenaline (NA) have been investigated in rats. Aortic strips showed a decreased responsiveness to EGDN and were more sensitive to NA than were control strips 2, 24 and 96 hrs after cessation of EGDN. Acute cumulative doses of EGDN induced a decrease in MAP at all time intervals but 2 hrs after cessation of chronic EGDN-treatment, while NA induced a dose-dependent increase in MAP. MAP was lower 2 hrs after cessation of EGDN, than in the control rats, while HR was higher. After 24 hrs, MAP was slightly higher than in the controls and HR was still elevated. EGDN induced a decrease in the accumulation of L-DOPA and DOPAC in all brain structures measured, which was especially prominent 2 hrs after cessation of EGDN. The levels of CA's and DOPAC in peripheral tissues did generally not change significantly, although there was a tendency to a decrease. L-DOPA, NA and adrenaline (A) in plasma decreased significantly, while DOPAC and dopamine (DA) increased. No consistent effects on uptake of NA into synaptosomes could be distinguished. However, the amount of protein was generally lower at all times after cessation of EGDN. It is suggested that prolonged exposure to EGDN not only induces tolerance at the cellular level, but also interferes with arterial smooth muscle sensitivity to NA and with resetting of MAP and HR. The decrease in the synthesis and turnover of CA's and DOPAC in the brain indicated a decrease in nervous activity, which is reflected by a corresponding decrease of NA and A levels in plasma.     

灯盏花素抑制去甲肾上腺素而增强高钾缩血管反应

目的　观察灯盏花素 (Bre)对去甲肾上腺素 (NA)和高钾所致缩血管反应的影响 ,研究其效应与细胞内游离钙浓度([Ca2 + ]i)变化的关系。方法　采用兔胸主动脉条 ,观察Bre对NA及高钾缩血管量效曲线、对NA和咖啡因在无钙液中所致短暂收缩及复钙后NA缩血管反应的影响 ;利用Fura 2 /AM负载的兔血管平滑肌细胞 ,观察在Bre存在下 ,由NA及高钾所增加的 [Ca2 + ]i的变化。结果　Bre呈剂量依赖性地使NA缩血管量效曲线非平行右移 ,最大反应压低 ,对高钾的量效曲线却呈增强作用 ;该药抑制NA及咖啡因在无Ca2 + 液中所诱发的短暂收缩及复Ca2 + 后NA所致缩血管反应 ;Bre抑制NA所致平滑肌 [Ca2 + ]i 的升高 ,而增强高钾升高 [Ca2 + ]i 的作用。结论　Bre通过抑制Ca2 + 内流和Ca2 +释放而抑制NA所致血管平滑肌的收缩 ,通过增强高钾所致Ca2 + 内流而增强其缩血管效应 ,但Bre增强高钾升高[Ca2 + ]i 的作用原理尚有待探讨     

Effect of Candida albicans septicemia on the cardiovascular function of rabbits

Candida albicans is an opportunistic pathogen that causes life-threatening systemic infection in immunocompromised host. However, little is known about the effects of yeast on the cardiovascular functions. This study examined the effects of C. albicans septicemia on the heart and vessel functions and nitric oxide (NO) production in infected rabbits. Anaesthetized animals were challenged with intravenous C. albicans (6 x 10(8)/kg) or saline and the blood pressure of rabbits were measured over 5 h. After that response of the isolated thoracic aorta, right atrium and left papillary muscle were recorded. Blood pressure significantly decreased in the infected rabbits during the septicemia but in the control animals it was stable. The blood nitrite levels and NO-synthases (eNOS, iNOS) expression and tissue nitrite levels in the heart and aorta were similar in the both groups. In the aorta isolated from C. albicans-infected rabbits, acetylcholine-induced endothelium-dependent relaxation was decreased, but contractions induced by phenylephrine were potentiated. The NOS inhibitor, L-N(G)-nitro-arginine methyl ester (L-NAME)-induced contraction increase in the right atrium was depressed by the yeast-infection. In the heart and aorta, microscopic examination revealed no tissue invasion of C. albicans. These results indicate the ability of C. albicans-induced septicemia to destroy NO-related responses of the heart and aorta and may have important implications for functional damage to endothelium and the regulation of cardiovascular functions. In addition, NOS induction and NO over-production are not stimulated by systemic C. albicans infection, which would alter the host immune reaction and homeostasis.     

Analysis of vasodilatory action of a new nitroester agent, 2-nicotinamidoethyl nitrate (SG-75).

Effects of 2-nicotinamidoethyl nitrate (SG-75) on cardiovascular system were investigated using whole animals and isolated vascular smooth muscles of dogs and rabbits. In dogs in vivo SG-75 i.v. produced dose-dependent falls in systemic blood pressure (SBP) concomitant with increases in heart rate (HR). Hypotension by SG-75 was not affected by propranolol and atropine but slightly inhibited by diphenhydramine. Norepinephrine (NE) dose-dependently increased SBP, and SG-75 could not affect these effects of NE. In dog coronary arterial strips contracted with potassium, SG-75 produced a dose-dependent relaxation of these strips. These effects of SG-75 were not affected by propranolol and atropine, but slightly inhibited by diphenhydramine. NE dose-dependently increased the tension of helical strips prepared from rabbit femoral artery, rabbit aorta and dog coronary artery. But SG-75 could not alter these effects of NE. The results suggest that SG-75 may have not an adrenergic beta-receptor stimulating action, a muscarinic action and an adrenergic alpha-receptor blocking action, but an inconsiderable histamine-like action. Probably, a main action of SG-75 may be a nitroglycerin-like action.     

Multiple effects of gymnopilin on circulatory system of the rat

Gymnopilin is one of the substances produced by the hallucinogenic mushroom, Gymnopilus junonius. In this study, we examined effects of gymnopilins purified from wild fruiting bodies of G. junonius on contractile activity of aorta preparations and blood pressure in rats. Gymnopilins at lower concentrations than 5?mg/mL did not evoke contraction of helical strips of the thoracic aorta. In contrast, gymnopilins (5?mg/mL) applied to the aorta strips pre-contracted by norepinephrine (100?nM) caused relaxation. This relaxing action did not depend on the activity of the endothelium cells. The relaxing effect of 5-mg/mL gymnopilins was observed in aorta strips contracted by angiotensin II (10?nM) and the high K⁺ solution (60?mM). Moreover, the adenylyl cyclase inhibitor, SQ-22536, significantly inhibited the relaxing effect of gymnopilins at 1?mg/mL on the norepinephrine-contracted strips. These results suggested that gymnopilins acted directly on smooth muscle cells of the aorta and activated the cAMP-dependent cascade to cause the vasodilation. Paradoxically, gymnopilins injection into the jugular vein transiently increased blood pressure without affecting the heart rate. This result suggests that gymnopilins increase cardiac output and/or tension of the artery through the excitation of the vasomotor nerve that overcame the direct relaxing effect on the vascular smooth muscle.     

人参皂苷Rg2对兔戊巴比妥钠心力衰竭的影响

目的观察人参皂苷Rg2(Rg2)对兔戊巴比妥钠心力衰竭的影响.方法复制戊巴比妥钠致心力衰竭模型,静脉注射Rg22.5,5.0和10.0mg/kg,观察对血流动力学的影响.结果Rg22.5,5.0和10.0mg/kg静脉注射,可加快HR,升高SBP,DBP,MAP,LVSP及±dp/dtmax.结论Rg2能改善心功能不全兔的血流动力学状况,具有强心作用.     

Involvement of endogenous noradrenaline release in methylene blue-induced contraction of isolated rabbit aorta

The vasocontractile response to methylene blue (Meb) was investigated in isolated rabbit aorta. Meb (1-100 microM) induced a slowly developing contraction after a long latency in rabbit aortic strip. The maximal contraction was obtained by 50 microM Meb, which corresponded to 1 microM noradrenaline (NA)-induced contraction. Once the maximal contraction was induced by Meb, the strip completely lost the contractile response to a further application of Meb. The usual NA-induced contraction, however, could be observed in such a Meb-insensitive aortic strip. Meb-induced contractions were not affected by atropine, diphenhydramine, methysergide, indomethacin, nordihydroguaiaretic acid and removal of endothelial cells from the aortic strip, but they were abolished by prazosin. In aortic strips from rabbits pretreated with reserpine (3.0 mg/kg, i.m.) for a day, Meb failed to induce contraction. Meb evoked the [3H] release from [3H]NA-preloaded aortic strips. In high performance liquid chromatographic analysis, a considerable amount of NA was found in the bathing fluid of the aortic strip in the presence of Meb. In addition, Meb pretreatment inhibited [3H]NA uptake by the aortic strip and abolished the contractile response to an electrical stimulation of adrenergic nerve terminals. Although Meb decreased the basal level of cyclic GMP in the aortic strip, Meb-induced [3H]NA release from the aortic strip was not affected by 8-bromo cyclic GMP. These results suggest that Meb-induced contraction of rabbit aorta is due to the release of endogenous NA from its storage pools of intramural adrenergic nerves through an independent mechanism of its cyclic GMP lowering effect. In addition, incubation of aortic strips with Meb resulted in depleting the storage NA and blocking the nerve function, suggesting that Meb might be useful for a pharmacological tool as an adrenergic neuron blocking agent in vitro.     

Lithium chloride-induced cardiovascular changes in rabbits are mediated by adenosine triphosphate-sensitive potassium channels.

The effect of lithium chloride on the mean arterial blood pressure, heart rate and heart contractility was evaluated in rabbits. The intravenous administration of 50 mg kg-1 lithium chloride as a bolus injection into rabbits produced a progressive decrease in the mean arterial blood pressure, heart rate and heart contractility during the 2-h period of investigation. Pretreatment of animals with 5 mg kg-1 glibenclamide, a potent inhibitor of adenosine triphosphate-sensitive potassium channels, markedly inhibited the cardiovascular changes induced by lithium chloride. Doubling the dose of glibenclamide nearly abolished these effects of lithium chloride. Similarly, lithium chloride produced a concentration- dependent relaxation of noradrenaline-induced contractions in isolated aortic strips of rabbits. This relaxant effect of lithium chloride was inhibited by pretreatment of the aortic strips with glibenclamide. Doubling the concentration of glibenclamide in the bathing fluid nearly abolished the effect of lithium. Diazoxide and verapamil potentiated the relaxant effect of lithium chloride on the isolated noradrenaline-contracted aortic strips. Pretreatment with glibenclamide markedly reversed the effect of diazoxide but not that of verapamil. The intravenous administration of lithium was also found to be capable of increasing the plasma potassium level and of decreasing the intracellular levels of adenosine triphosphate in cardiac and vascular tissues in a time-dependent manner. The plasma sodium and calcium levels were not changed. These results provide evidence that the hypotensive and cardiac depressant effects of lithium chloride are mediated by activation of adenosine triphosphate-sensitive potassium channels.     

Hemodynamic effects of di-sec-butyl phenol, an anesthetic substituted phenol

Dose- and age-related hemodynamic effects were determined for an anesthetic substituted phenol, 2,6-di-sec-butyl phenol (DSB). DSB, 7.5 mg/kg, induced hypnosis in young rabbits and increased mean blood pressure to 170 +/- 14% and heart rate to 150 +/- 21% of control values. In elderly rabbits, 7.5 mg/kg DSB induced hypnosis, had no effect on blood pressure, but increased the heart rate to 130 +/- 2% of control. After ganglionic blockade with hexamethonium, 7.5 mg/kg DSB caused a decline in mean blood pressure (71 +/- 5% of control) without change in heart rate. DSB increased norepinephrine release from SH-SY5Y cells, a human neuroblastoma cell line (5.4 +/- 1.7% vs. 3.5 +/- 0.3%). DSB produced age-dependent elevation of mean blood pressure in rabbits, probably by causing release of catecholamines from the sympathetic nervous system.     

Studies on some para-substituted clonidine derivatives that exhibit an alpha-adrenoceptor stimulant activity.

1 alpha-Adrenoceptor stimulant activity was determined for noradrenaline (NA), clonidine and a series of para-substituted derivatives of clonidine on rat aortic strips, a rat brain synaptosome preparation, and anaesthetized pithed rats. The effects on the blood pressure of intraventricular (i.c.v.) injections of para-aminoclonidine were also determined in anaesthetized rats. 2 Para-substituted derivatives of clonidine (amino-, diethylamino-, ethylamino-, acetamido-, bromoacetamido-, N-chloroethyl-N-methyl-amino and N-beta-chloroethyl-N-methylaminomethyl-) retain alpha-adrenoceptor stimulant activity. 3 pD2 values determined on rat aortic strips were 11.2, 7.67 and 9.05 respectively for para-aminoclonidine, clonidine and noradrenaline. The Ki values of these agents, determined on a rat brain synaptosomal preparation with a radioreceptor assay using [3H]-clonidine as ligand, were 1.3, 8.0 and 23 nM respectively for para-aminoclonidine, clonidine and NA. When given by i.c.v. injection in rats, para-aminoclonidine lowered the blood pressure. 4 N-beta-chloroethyl-N-methylaminomethylclonidine is an alkylating agent with an unusual agonist activity. It elicits contractions of the rat aorta that persist despite repeated washing. 5 alpha-Adrenoceptor affinities are discussed in relation to their structural features.