Influence of propranolol and pindolol on the haemodynamic effects of papaverine,isoprenaline and noradrenaline in hypertensive patients

Summary The influence of two -adrenoceptor antagonists, propranolol and pindolol, on the haemodynamic effects of papaverine, isoprenaline and noradrenaline was investigated in 9 male patients with first degree essential hypertension. Propranolol and pindolol were given according to a doubleblind, crossover scheme. Heart rate and blood pressure were measured before and after each treatment. Propranolol 670 µg/kg i. v. reduced the supine and standing systolic blood pressures by 2.3% and 1.6%, respectively. Similarly, the intravenous administration of pindolol 35 µg/kg reduced supine and standing systolic blood pressure by 5.5% and 8.3% respectively (clinically insignificant). Neither drug affected diastolic blood pressure. Following propranolol, there were moderate reductions in supine and standing heart rates, respectively by 24% and 20% (p<0.001). Similarly, but to a lesser extent, pindolol reduced supine and standing heart rate by 12% and 17% (p<0.001). The effects of papaverine, which, at 1.5 mg/kg i. v. reduced systolic blood pressure by 5–10% and increased heart rate by 8–15%, were not significantly influenced by the -blockers. The blood pressure and heart rate responses to isoprenaline, on the other hand, were attenuated or inhibited by both -blockers. While the -blockers inhibited the -adrenoceptor component of noradrenaline, the pressor component of noradrenaline, which is mediated through the -adrenoceptors, was not influenced by propranolol, but was inhibited after pindolol. It is concluded that pindolol differs qualitatively from propranolol in that it inhibited both the -and -adrenoceptor effects of noradrenaline.Abbreviations BP blood pressure - ECG electrocardiogram - HR heart rate - ISA intrinsic sympathomimetic activity     

The effect of urapidil on responses to phenylephrine,angiotensin and isoprenaline in man

Summary Intravenous urapidil, 40 mg bolus followed by an infusion of 18 mg·h^–1 for 2 h was administered to 6 female non-patient volunteers. Randomised cumulative dose response curves to angiotensin, phenylephrine and isoprenaline were performed before and commencing 30 min after the start of the infusion of urapidil. Urapidil significantly reduced supine systolic blood pressure, 118.5 mm Hg to 105.3. The diastolic blood pressure was not significantly reduced, heart rate was not affected. Urapidil did not affect the responses to angiotensin or isoprenaline. Urapidil inhibited the pressor response to phenylephrine. The dose required to increase systolic blood pressure by 20 mm Hg increased from 156.9 g·min^–1 before to 685 g·min^–1 during urapidil; Dose ratio from individual values of 4.58. Urapidil concentrations were not significantly different before and after each agonist infusion. It is concluded that urapidil has ₁-adrenoceptor blocking activity in man without any non specific vasodilator action and that it is devoid of beta adrenoceptor blocking action.     

BRL-37344对心力衰竭大鼠β肾上腺素受体表达水平的影响(英文)

目的　探讨 β3 肾上腺素受体 (β3 AR)及其激动剂BRL 37344 (BRL)在心力衰竭中的作用。方法大鼠分为对照组、异丙肾上腺素 (Iso)组和Iso +BRL组。Iso组和Iso +BRL组大鼠间隔 2 4h ,scIso 340mg·kg- 12次制作心力衰竭模型。 8周后 ,Iso +BRL组大鼠从尾静脉给予BRL 0 .4nmol·kg- 1·min- 1,10min ,每周 2次 ,给药 2或 6周。分别于给Iso后 10或 14周测定死亡率、血流动力学、左室重 /体重、心肌组织 β1 ,β2 和 β3 ARmRNA水平。结果　 14周时对照组、Iso组和Iso +BRL组分别死亡 0 / 2 0 ,3/ 18和 5 / 2 2 (P >0 .0 5 )。Iso使左室收缩末压、±dp/dtmax明显降低 ,左室等容舒张时间常数、左室舒张末压明显增高 ,左室重 /体重明显增加 ;与Iso组比 ,Iso +BRL组的心脏舒缩功能进一步下降 ,左室重 /体重进一步增加。Iso组 β1 ARmRNA水平降低 ,β3 ARmRNA水平升高 ,与Iso组比较 ,Iso +BRL组 β1 ARmRNA水平更低 ,β3 ARmRNA水平更高。β2 ARmRNA 3组均有下降趋势 ,但无统计学差异。结论衰竭心脏β1 AR水平下降及 β3 AR水平增高可导致心功能降低。β3 ARmRNA水平在衰竭心脏比非衰竭心脏明显增高 ,应用 β3 AR激动剂可明显加重心力衰竭。     

1,6-二磷酸果糖镁盐对大鼠实验性心肌线粒体损伤的治疗作用

 目的观察1,6-二磷酸果糖镁盐(FDP-Mg)对由异丙肾上腺素(Iso)诱导的心肌线粒体缺血性损伤的治疗作用。方法采用皮下多点注射Iso致大鼠心肌缺血损伤模型,静脉分别予FDP-Mg100mg·kg^-1及FDP-Na120mg·kg^-1和MgSO₄30mg·kg^-1进行治疗,观察心肌细胞及线粒体超微结构的变化,测定药物对缺血损伤的心肌细胞内的线粒体膜电位的影响及对线粒体肿胀的抑制率。同时利用黄嘌呤/黄嘌呤氧化酶氧自由基发生系统和CuSO₄/细胞色素C羟自由基发生系统分别检测药物对超氧阴离子(O₂^-)和羟自由基(·OH)的清除率。结果FDP-Mg可以显著改善由Iso所诱导的线粒体膜电位异常改变,抑制线粒体肿胀。且对·OH和O₂^-有较高的清除率,与对照组相比有显著差异。电镜显示FDP-Mg对维持线粒体的正常形态有明显作用。结论FDP-Mg可有效保护由Iso所致的心肌细胞的线粒体实验性缺血损伤。     

异丙肾上腺素对心肌细胞内钙释放和肌浆网内钙容量的影响

目的 :心肌细胞膜上的 β-肾上腺素受体的激活对兴奋 -收缩耦联 （ECC）过程有重要的调节作用。本课题利用异丙肾上腺素 （ISO,1μmol/ L）激活 β-肾上腺素受体从而研究其对源自心肌细胞肌浆网的胞内钙释放 （ECC的重要环节 ）和肌浆网内钙容量的影响 ,进而分析钙释放与钙容量之间的关系。方法 :局部场刺激作用于成年大鼠心肌细胞 ,促使后者产生动作电位 ,进而诱发胞内钙瞬变 （ACT） ,由 ACT可估测胞内钙释放。肌浆网内钙容量则由咖啡因 （2 0 m mol/ L）诱发的钙瞬变 （CCT）估测。实验结果均由 Zeiss L SM- 5 10激光共聚焦显微镜系统记录。结果 :ISO作用下的 ACT峰值为 10 .2 9± 0 .35 （n=13）比正常情况下的 5 .74± 0 .2 7（n=18）高 （P<0 .0 1）。 ISO作用下的CCT峰值为 11.2 3± 0 .2 9（n=13）比正常情况下的 7.6 2± 0 .2 4 （n=18）高 （P<0 .0 1）。结论 :ISO可明显地提高心肌细胞内钙释放量和肌浆网内的钙容量。不管有无 ISO存在 ,胞内钙释放量总是只占肌浆网内钙容量的一部分。在正常情况下 ,心肌的钙释放量有较大的储备能力 ,且此储备可因β-肾上腺素受体的激活而动员。     

Phloroglucinol averts isoprenaline hydrochloride induced myocardial infarction in rats

Myocardial infarction (MI) is indicated by the symptoms like sharp chest pain, sweating, palpitations, and nervousness finally leading to heart attack. MI occurs mainly due to the risk factors like smoking, elevated blood pressure, diabetes, hypercholesterolemia, obesity, decreased HDL level, elevated LDL level, hyperlipoproteinemia and aging consequently leads to demandable coronary blood supply, oxidative stress, and acute necrosis of the myocardium. Cardioprotective potential of the phloroglucinol (PG) was assessed by treating isoprenaline hydrochloride (ISO; 85 mg/kg b.w., s.c.) induced MI model in rats. Pretreatment with PG in a dose of 30 mg/kg was done for 28 days and followed by ISO (for MI induction) on 29th and 30th days, exhibited decline in the abnormalities in the ECG patterns, cardiac marker enzymes, enzymic and nonenzymic antioxidants, lipid peroxidation, lipid profiles, and histopathological investigations compared to isoprenaline alone treated group. On the whole, the present investigations elucidate the significance of PG in alleviating the pathological process and appreciably prevent the induction of MI in experimental rats.     

乙酰胆碱和组织胺对豚鼠离体气管条张力的影响及机制分析

用自制的多个“工”形相连的豚鼠气管条,观察乙酰胆碱、组织胺和异丙基肾上腺素对肌张力的影响,探讨钙激活钾(KC_a)通道功能的变化。结果显示:1.乙酰胆碱和组织胺共同作用时,平滑肌张力升高幅度大于乙酰胆碱和组织胺单独作用,小于两者单独作用之和。2.异丙基肾上腺素引起乙酰胆碱或组织胺所致平滑肌张力下降,甚至低于基础张力,乙酰胆碱和组织胺共同作用时,异丙基肾上腺素也可解痉。结果提示:中等浓度乙酰胆碱和组织胺对增加气管平滑肌张力有协同作用。异丙基肾上腺素引起乙酰胆碱或组织胺所致平滑肌张力下降,表明乙酰胆碱和组织胺引起气管平滑肌痉挛时,KC_a通道处于关闭或大部分关闭状态。     

西洋参茎叶皂甙对实验性心肌坏死的保护作用

研究西洋参茎叶皂甙（ＰＱＳ）对应激状态下心肌缺血坏死的保护作用。ｉｇＰＱＳ５０、１００ｍｇ·ｋｇ－１，能明显减少心肌坏死面积，降低血清ＣＫ、ＬＤＨ活性。表明ＰＱＳ具有保护作用。同时ＰＱＳ能降低血清ＦＦＡ水平，减少心肌ＬＰＯ含量。提示其抗心肌缺血作用可能与纠正心肌缺血时ＦＦＡ代谢紊乱及对抗氧自由基引发的脂质过氧化反应有关。     

活血养阴颗粒对异丙肾上腺素诱导大鼠心肌缺血的保护作用

目的研究活血养阴颗粒对异丙肾上腺素造成急性心肌缺血模型大鼠的保护作用。方法采用异丙肾上腺素造成大鼠急性心肌缺血模型。结果活血养阴颗粒可对抗异丙肾上腺素所致心肌缺血大鼠的心电图T波抬高及S-T段的异常偏移,使血清乳酸脱氢酶(LDH)降低,并可增加心肌组织超氧化物歧化酶(SOD)的活力,减少丙二醛(MDA)生成。结论活血养阴颗粒对大鼠急性心肌缺血有一定的保护作用。     

Comparison of α- and β-Receptor Stimulation in the Circular and Longitudinal Muscle of the Oestrogen and Progesterone Dominated Rabbit Uterus

Abstract: Longitudinal and circular muscle strips from the progesterone-dominated rabbit uterus were stimulated in vitro with the α- and β-adrenergic agents noradrenaline and isoprenaline, and the effects were compared with results obtained from the oestrogen-dominated uterus. The spontaneous activity in oestrogen- and progesterone-dominated strips was the same. Noradrenaline caused an increase in frequency and basal tone in all strips. In the oestrogen-dominated strips the force of the induced contractions exceeded the force of the spontaneous contractions. In the progesterone-dominated strips the force of the contractions subsequent to the addition of noradrenaline was usually a little reduced. No difference between the circular and longitudinal strips was observed. Reserpine-treatment of the oestrogen-dominated animals substantially reduced the force of the noradrenaline-induced contractions. In progesterone-dominated animals reserpine treatment had no such effect. Isoprenaline produced a reduction in the force and the frequency of the spontaneous contractions. In the circular strips, the spontaneous activity was less inhibited by isoprenaline in the progesterone than in the oestrogen-dominated strips. As to the longitudinal strips, the dose-response curves were quite similar. The circular strips were much less inhibited by isoprenaline than were the longitudinal ones. It is concluded that the different reactions to adrenergic nerve stimulation in oestrogen- and progesterone-dominated rabbit uteri reported previously by other investigators, might depend on the different reactions of the muscle to α stimulation, this difference being partly explained by the higher catecholamine content of the oestrogen-dominated tissue.