McPherson G A, Malta E, Raper C
J Cardiovasc Pharmacol. 1981 Jul-Aug;3(4):739-52. doi: 10.1097/00005344-198107000-00008.
The effects of intravenous infusions of norepinephrine, epinephrine, isoproterenol, N-t-butylnorepinephrine, oxymethyleneisoproterenol, and RO363 on heart rate, mean arterial blood pressure, cardiac output, total peripheral resistance, and stroke volume were evaluated in chloralose-anaesthetized cats before and after phentolamine, propranolol, atenolol, and butoxamine. Pressor responses to both norepinephrine and epinephrine largely resulted from alpha-receptor-mediated increases in total peripheral resistance. Vasomotor reversal was noted with both drugs in the presence of alpha-receptor blockade. Dilator responses to norepinephrine were abolished by the beta 1-receptor selective antagonist atenolol, as were those to the beta 1-receptor selective agonists oxymethyleneisoproterenol and RO363. Dilator responses to epinephrine were abolished by the beta 2-receptor selective antagonist butoxamine, as were those to N-t-butylnorepinephrine (beta 2-selective) and isoproterenol (nonselective). These results indicate that in addition to beta 2-receptors, beta 1-receptors subserving vasodilatation occur in the cat vasculature. Atenolol displayed agonist-dependent inhibition of the cardiac responses. Responses to noradrenaline, RO363, and oxymethyleneisoproterenol were blocked to a greater extent than were those to epinephrine, N-t-butylnorepinephrine, and isoproterenol. Butoxamine did not display any marked agonist-dependent inhibition of cardiac responses. Nevertheless, the results are in accord with previous suggestions that cardiostimulant beta 2-receptors exist in the cat heart. Interpretation of the actions of catecholamines may be complicated by mixed beta-adrenoceptor populations in the cat cardiovascular system.
在水合氯醛麻醉的猫中，分别于给予酚妥拉明、普萘洛尔、阿替洛尔和布托沙明之前及之后，评估了静脉输注去甲肾上腺素、肾上腺素、异丙肾上腺素、N -叔丁基去甲肾上腺素、甲氧亚甲基异丙肾上腺素和RO363对心率、平均动脉血压、心输出量、总外周阻力和每搏输出量的影响。对去甲肾上腺素和肾上腺素的升压反应主要源于α受体介导的总外周阻力增加。在存在α受体阻断的情况下，两种药物均出现血管运动反转。对去甲肾上腺素的舒张反应被β1受体选择性拮抗剂阿替洛尔消除，对β1受体选择性激动剂甲氧亚甲基异丙肾上腺素和RO363的舒张反应也被消除。对肾上腺素的舒张反应被β2受体选择性拮抗剂布托沙明消除，对N -叔丁基去甲肾上腺素（β2选择性）和异丙肾上腺素（非选择性）的舒张反应也被消除。这些结果表明，除了β2受体外，猫血管系统中还存在介导血管舒张的β1受体。阿替洛尔表现出激动剂依赖性的心脏反应抑制作用。对去甲肾上腺素、RO363和甲氧亚甲基异丙肾上腺素的反应比对肾上腺素、N -叔丁基去甲肾上腺素和异丙肾上腺素的反应受到更大程度的阻断。布托沙明未表现出任何明显的激动剂依赖性心脏反应抑制作用。然而，这些结果与之前关于猫心脏中存在心脏兴奋β2受体的观点一致。猫心血管系统中混合的β肾上腺素能受体群体可能会使儿茶酚胺作用的解释变得复杂。
