Einstein R, Goodman A H, Yeoh E B
J Auton Pharmacol. 1986 Mar;6(1):9-14. doi: 10.1111/j.1474-8673.1986.tb00625.x.
The cardiovascular effects of some beta-adrenoreceptor agonists on heart rate, blood pressure and myocardial contractility (maximum rate of change of left ventricular pressure/integrated isometric tension) were measured in pentobarbitone-anaesthetised and conscious, instrumented greyhounds. In anaesthetised dogs isoprenaline increased heart rate and myocardial contractility and reduced blood pressure. Prenalterol and RO 363, in equiactive inotropic doses, induced greater increases in heart rate than isoprenaline if blood pressure fell by less than 25 mmHg. Salbutamol had hypotensive activity at all doses and appeared to be a relatively selective inotrope. None of the agonists caused blood pressure to fall in the conscious dogs. Prenalterol and RO 363 were more effective inotropic stimulants, producing smaller increases in heart rate and more pronounced increases in myocardial contractility. Salbutamol, however, elicited greater increases in heart rate in the conscious animals and the inotropic selectivity demonstrated in the anaesthetised animals was lost. The direct effects of the beta-adrenoreceptor agonists, without modification by reflexes could be observed in the anaesthetised animals. The differences in the actions of the agonists in the conscious animals appear to be attributable to the state of the baroreceptor reflex control system and the relatively enhanced responsiveness of the heart.
在戊巴比妥麻醉且装有仪器的灵缇犬以及清醒的装有仪器的灵缇犬身上，测量了一些β - 肾上腺素能受体激动剂对心率、血压和心肌收缩力（左心室压力最大变化率/等长张力积分）的心血管效应。在麻醉犬中，异丙肾上腺素可增加心率和心肌收缩力，并降低血压。普瑞特罗和RO 363在等活性变力剂量下，如果血压下降小于25 mmHg，比异丙肾上腺素引起的心率增加更大。沙丁胺醇在所有剂量下均有降压活性，似乎是一种相对选择性的变力剂。在清醒犬中，没有一种激动剂会导致血压下降。普瑞特罗和RO 363是更有效的变力刺激剂，引起的心率增加较小，而心肌收缩力增加更明显。然而，沙丁胺醇在清醒动物中引起的心率增加更大，并且在麻醉动物中表现出的变力选择性丧失。在麻醉动物中可以观察到β - 肾上腺素能受体激动剂未经反射调节的直接效应。激动剂在清醒动物中的作用差异似乎归因于压力感受器反射控制系统的状态以及心脏相对增强的反应性。
