Satoh K, Nunoki K, Goto T, Taira N
J Cardiovasc Pharmacol. 1985 May-Jun;7(3):508-15. doi: 10.1097/00005344-198505000-00015.
The mechanism of the vasodilator action of bunitrolol was investigated in pentobarbital-anesthetized dogs. When injected intraarterially, bunitrolol increased blood flow through the femoral arterial bed more effectively than that through the vascular bed of the left anterior descending coronary artery (LAD). The former is rich in alpha-adrenoceptors and tonically controlled by the sympathetic nerves, whereas the latter is not. Intraarterial prazosin increased femoral flow but not LAD flow, whereas intraarterial nitrendipine increased equieffectively both femoral and LAD flows. In the saphenous arterial bed of dogs that also underwent spinal anesthesia and received atropine and nadolol, intravenous bunitrolol suppressed more effectively vasoconstrictor responses to saphenous nerve stimulation than those to intraarterial norepinephrine. These effects of bunitrolol were similar to those of prazosin and dissimilar to those of yohimbine. In similarly treated dogs, bunitrolol suppressed more effectively increases in mean systemic arterial pressure in response to methoxamine than those to B-HT 920. From these results, it was concluded that an alpha 1-adrenoceptor blocking action is mainly involved in the acute vasodilator effect of bunitrolol. This action may also contribute to the decrease in total peripheral resistance seen in hypertensive patients treated chronically with bunitrolol.
在戊巴比妥麻醉的犬中研究了布尼洛尔的血管舒张作用机制。动脉内注射时，布尼洛尔增加股动脉床血流量的效果比增加左前降支冠状动脉（LAD）血管床血流量的效果更显著。前者富含α-肾上腺素能受体并受交感神经的紧张性控制，而后者则不然。动脉内注射哌唑嗪可增加股动脉血流量，但不增加LAD血流量，而动脉内注射尼群地平可同等有效地增加股动脉和LAD血流量。在也接受脊髓麻醉并给予阿托品和纳多洛尔的犬的隐动脉床中，静脉注射布尼洛尔比动脉内注射去甲肾上腺素更有效地抑制对隐神经刺激的血管收缩反应。布尼洛尔的这些作用与哌唑嗪的作用相似，与育亨宾的作用不同。在同样处理的犬中，布尼洛尔比B-HT 920更有效地抑制对甲氧明的平均体动脉压升高。从这些结果得出结论，α1-肾上腺素能受体阻断作用主要参与布尼洛尔的急性血管舒张作用。这种作用也可能有助于长期接受布尼洛尔治疗的高血压患者总外周阻力的降低。
