Bonelli J, Magometschnigg D, Hitzenberger G, Kaik G
Int J Clin Pharmacol Biopharm. 1977 Aug;15(8):381-3.
The study was conducted in six healthy male volunteers aged between 20 and 30 years. Cardiac output was determined by means of the Swan-Ganz-thermodilution-method. A control-study was carried out, during which an isoproterenolinfusion with increasing doses was given. Fifty minutes after i.v. injection of a beta-receptor-blocker the hemodynamic parameters were measured again under increasing doses of isoproterenol until the block was overcome. This study procedure was performed twice in each subject at an interval of at least 14 days. For the one study 15 mg propranolol i.v. and for the other 0,5 mg mepindolol i.v., a new beta-receptor-blocker, were injected. After i.v. injection of propranolol the dose-response-relationship-curve for the heart-rate (HR) and stroke volume (SV) describes a definite shift to the right. After mepindolol the dose-effect curve for the heart rate describes a definite shift to the right, as seen with propranolol. In contrast, only a very slight shift can be seen in respect of the SV increase, i.e. the SV and HR curves dissociate under mepindolol. The results of our study indicate, that a distinction can be made with respect to the so-called beta 1-receptors between those mediating a specific effect on the heart-rate and those mediating a mainly positive inotropic effect.
该研究在6名年龄在20至30岁之间的健康男性志愿者身上进行。心输出量通过Swan-Ganz热稀释法测定。进行了一项对照研究，在此期间给予递增剂量的异丙肾上腺素输注。静脉注射β受体阻滞剂50分钟后，在递增剂量的异丙肾上腺素作用下再次测量血流动力学参数，直至阻滞被克服。每个受试者以至少14天的间隔重复此研究过程两次。一项研究静脉注射15mg普萘洛尔，另一项研究静脉注射0.5mg美哌洛尔（一种新的β受体阻滞剂）。静脉注射普萘洛尔后，心率（HR）和每搏输出量（SV）的剂量反应关系曲线明显向右偏移。与普萘洛尔一样，美哌洛尔注射后心率的剂量效应曲线也明显向右偏移。相比之下，在SV增加方面仅可见非常轻微的偏移，即在美哌洛尔作用下SV和HR曲线分离。我们的研究结果表明，在介导对心率的特定作用和介导主要正性肌力作用的所谓β1受体之间可以做出区分。
