Effect of phentolamine on noradrenaline uptake and release

Summary The influence of phentolamine on the uptake of exogenous noradrenaline infused into the aortic cannula and on the overflow of endogenous noradrenaline caused by sympathetic nerve stimulation was investigated in the isolated perfused rabbit heart. 10^–6 M phentolamine doubled the overflow of endogenous noradrenaline, but did not change noradrenaline uptake. 10^–5 M phentolamine increased the stimulation-induced overflow of noradrenaline 4-fold and inhibited amine uptake by about 50%. 10^–4 M phentolamine elevated the overflow of noradrenaline less than 10^–5 and 3×10^–5 M did. The augmentation of transmitter overflow was only partly reversed by 13 min perfusion with drug-free medium.Pretreatment of hearts with 1.5×10^–5 M cocaine or with 10^–7 or 10^–6 M desipramine did not change the effect of phentolamine on the overflow of noradrenaline evoked by nerve impulses. Pretreatment of hearts with 10^–5 M, but not with 10^–6 M, phentolamine prevented the increase of transmitter overflow by cocaine.It is concluded that low concentrations of phentolamine potentiate the overflow of noradrenaline during nerve stimulation by a mechanism different from that of cocaine, i.e. different from inhibition of neuronal re-uptake. The nature of this mechanism is discussed.This work was supported by the Deutsche Forsehungsgemeinschaft. We have the pleasure to thank Mrs. Ch. Arts, Miss B. Piel and Mr. E. Hagelskamp for skilful technical assistance.     

蒲公英与白屈菜合用对兔离体肠管的作用

蒲公英白屈菜水煎剂(TCD)能显著降低肠管蠕动频率和幅度,给药10min 降低肠管蠕动频率和幅度分别为对照组的56.6%和46.2%。二者与阿托品对照组比较作用明显,且维持时间较长。给药后20min降幅度作用为阿托品的43.1%两者比较差异显著(P<0.05)。实验结果还表明 TCD 对乙酰胆碱,组织胺引起的肠痉挛具有明显对抗作用。     

Effect of phentolamine on the electroencephalogram and pulse activity of the cortical neurons

In tests with vigilant immobilized and also urethan anesthetized rabbits the influence of intravenous injection of phentolamine (3--10 mg/kg) on the EEG waves parameters was studied. It is shown that within 45 to 75 minutes following introduction of phentolamine there is observed either shortening or elimination of the EEG activation reaction in response to stimulation of the sciatic nerve. The blocking effect of the intravenous administration of phentolamine is noted also by following dynamic changes in the discharge activity of single neurons.     

Effect of phentolamine and anaprilin on the makeup and distribution of electrolytes in the myocardium]

Acute tests with rats demonstrated that the adrenoblocking agent phentolamine acts predominantly on the potassium level in the myocardium, raising its total, intra- and extra-cellular content. The effect of anapriline was mainly on sodium. Thyramine, which like adrenoblocking agents displays a catecholine-reducing effect, did not produce any similar changes in the potassium and sodium content.     

酚妥拉明联合垂体后叶素治疗支气管扩张咯血的疗效观察

目的探讨酚妥拉明联合垂体后叶素治疗支气管扩张咯血的临床疗效。方法将72例患者随机分为观察组和对照组（各36例）,对照组在综合性基础治疗上给予垂体后叶素治疗,观察组在对照组治疗的基础上加用酚妥拉明治疗。结果观察组总有效率为97．2％,明显优于对照组的77．8％,两组总有效率比较差异具有统计学意义（P〈0．05）。结论应用酚妥拉明联合垂体后叶素治疗支气管扩张咯血疗效显著,具有起效快、安全可靠、不良反应少等优点,值得临床推广。     

Effect of propranolol and phentolamine on myocardial necrosis after subarachnoid haemorrhage.

A study was set up to assess the effect on the clinical course of subarachnoid haemorrhage (SAH) of giving propranolol 80 mg eight-hourly plus phentolamine 20 mg three-hourly by mouth for three weeks. Out of the 90 patients studied, 14 died. Two of the deaths occurred in an open pilot study of 10 patients, the remaining 12 deaths occurring in patients in a randomised double-blind placebo-controlled study. Postmortem examination was carried out on 12 of the patients, six of whom had been receiving placebo and six propranolol plus phentolamine. Necrotic myocardial lesions were present in the hearts of all six patients (age range 30-59 years) who died while taking placebo (all had had abnormal electrocardiograms (ECGs). In contrast, no necrotic lesions were found in the hearts of the six patients (age range 28-59) who died while receiving the drugs (all had previously had normal ECGs). We conclude that the necrotic myocardial lesions were induced by catecholamines and that propranolol had a cardioprotective effect. While death from a further haemorrhage in cases of SAH is not affected by propranolol and phentolamine, propranolol may have a beneficial effect in other potentially lethal stresses.     

酚妥拉明对野百合碱引起的大鼠肺动脉高压的影响

本文研究结果表明:野百合碱是一个有效的引起Wistar大鼠肺动脉高压模型的药物;酚妥拉明(0.2mg·kg~(-1)0.4mg·kg~(-1))im.每天2次.连续用药21d后.可降低野百合碱引起的肺动脉高压.但对股动脉血压无明显影响。酚妥拉明(0·52mg·kg~(_1))iv一次即可明显降低野百合碱引起的大鼠肺动脉高压和股动脉压。     

Effect of phentolamine on peripheral venous distensibility in congestive heart failure

Summary Seven patients with congestive heart failure received an infusion of phentolamine, 5 mg per hour for one hour, and seven others, considered as controls, received an infusion of dextrose. The small dose of phentolamine produced a minimal increase in pulse rate, and no significant change in arterial blood pressure and forearm blood flow. Venous distensibility was measured in the forearm by occlusion plethysmography. It was significantly increased by phentolamine, the rise in venous volume being 20–30% greater than in controls for the same effective venous pressure.     

拉贝洛尔联合酚妥拉明对妊娠期高血压患者的疗效

目的探讨拉贝洛尔联合酚妥拉明对妊娠期高血压患者妊娠结局及爱帕琳肽(Apelin)、血栓调节蛋白(PTM)水平的影响。方法本研究为随机对照试验。选择2019年2月至2022年2月临沂市人民医院收治的86例妊娠期高血压患者为研究对象, 以随机数字表法分为观察组(43例)与对照组(43例)。对照组年龄(29.12±3.93)岁, 孕周(29.63±4.12)周;观察组年龄(28.23±3.19)岁, 孕周(31.01±4.13)周。对照组采用酚妥拉明治疗, 观察组在对照组的基础上给予拉贝洛尔治疗, 两组均持续治疗7 d后观察效果。对比两组患者的临床疗效及不良妊娠结局, 比较治疗前后Apelin、PTM水平。统计学方法采用χ2检验、独立样本t检验、配对t检验。结果观察组患者的临床总有效率高于对照组[93.02%(40/43)比76.74%(33/43)], 两组比较差异有统计学意义(χ2=4.440, P=0.035)。治疗前, 两组患者的Apelin、PTM水平比较差异均无统计学意义(均P>0.05);治疗后, 两组的Apelin、PTM均降低, 且观察组患者的Apelin、PTM水平...     

Effect of diazoxide on capacitance vessels

Summary Haemodynamic changes after an i. v. bolus of diazoxide 300 mg were studied in 11 hypertensive subjects. A hypotensive effect due to a fall in total peripheral vascular resistance was found in all of them, but changes in the peripheral circulation were less regular. A uniform change in forearm blood volume, blood flow, vascular resistance and venous distensibility was not found after diazoxide. This is interpreted as being due to a reflex increase in sympathetic activity, which counteracts the direct vasodilator action of the drug.     

Effect of intrahypothalamic phentolamine on hypothermia produced by peripheral noradrenaline in the pigeon.

1 The effect of intrahypothalamic phentolamine (1 and 1 microliter of a 10 microgram/microliter solution) on hypothermia induced by intramuscular injection of noradrenaline (NA, 2 mg/kg) at different times (2, 10, 20 min) after phentolamine was investigated in pigeons. 2 Administration of phentolamine shortly before NA was shown to attenuate hypothermic responses to NA. 3 It is suggested that the attenuation is due to blockade of central hypothermic effects of intramuscular NA. 4 The mapping of injection sites in the brains was carried out.     

Effect of guanethidine on α-adrenoceptor blocking potency of phentolamine in vitro

The effect of guanethidine on the α-adrenoceptor blocking property of phentolamine was studied using the rabbit aortic strip and rat vas deferens. The agonists used were noradrenaline (in presence of DOCA and cocaine which block uptake mechanisms) and xylometazone (which is not taken by uptake mechanisms). Guanethidine augmented the responses to noradrenaline and xylometazoline and increased the pA₂ value of phentolamine against both agonist. Increased affinity of α-receptors may be partly responsible for the guanethidine-induced supersensitivity to α-adrenoceptor agonists.