Circulatory effects of angiotensin II during anaesthesia, evaluated by real-time spectral analysis
Circulatory effects of angiotensin II during anaesthesia, evaluated by real-time spectral analysis
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DOI：
10.1034/j.1399-6576.2003.00114.x
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发表时间：
2003-05-01
影响因子：
2.1
通讯作者：
Rundgren, M
中科院分区：
文献类型：
--
作者：
Ullman, J;Härgestam, R;Rundgren, M
背景：全身麻醉可刺激肾素-血管紧张素系统。外源性给药血管紧张素II升高血压主要是通过增加总外周阻力引起的直接血管收缩作用。血管紧张素II的降压作用涉及脑介导的成分，这也得到了很好的证实。异氟醚麻醉大大降低血管内输注血管紧张素II的降压作用。一个可能的机制是异氟醚麻醉降低了血管紧张素II对血压的影响，这涉及到对自主神经活动的影响。在一项绵羊实验研究中，我们利用动脉血压信号的实时频谱分析，分别获得异氟醚麻醉期间副交感神经、交感自主神经活动对血管紧张素II的反应。方法：对清醒和异氟醚麻醉的绵羊进行研究，在20分钟内颈动脉内输注血管紧张素II (85 ng kg(-1) min(-1))，随后30分钟恢复期，然后静脉注射血管紧张素II， AT(1)受体拮抗剂氯沙坦（10 mg kg(-1)）。监测全身和局部（肾脏和股）循环，并实时频谱分析动脉血压信号。结果：异氟醚麻醉降低了血管紧张素ⅱ输注后高血压反应的程度和持续时间。表示交感神经激活的频带的功率谱密度与有意识动物的平均动脉压变化相关，但在异氟醚麻醉期间则无关。结论：我们得出结论，循环血管紧张素II的高血压作用的脑介导成分在很大程度上被异氟醚麻醉消除。血压信号的频谱功率分析表明，脑血管紧张素II的作用涉及交感神经活动的激活。
Background: General anaesthesia may stimulate the renin-angiotensin system. Exogenous administration of angiotensin II elevates blood pressure mainly via increased total peripheral resistance caused by direct vasoconstrictor actions. It is also well established that the hypertensive effect of angiotensin II involves a cerebrally mediated component. The hypertensive effect of an intravascular infusion of angiotensin II is substantially reduced by isoflurane anaesthesia. A likely mechanism is that isoflurane anaesthesia reduces the cerebral component of the angiotensin II effect on blood pressure, which involves influences on autonomic nervous activity. In an experimental study in sheep we used real-time spectral analysis of arterial blood pressure signals to obtain information on parasympathetic, respectively, sympathetic autonomic nervous activity in response to angiotensin II administration during isoflurane anaesthesia.Methods: The study was performed on conscious and isoflurane-anaesthetized sheep that were subjected to an intracarotid infusion of angiotensin II (85 ng kg(-1) min(-1) ) during 20 min followed by a recovery period of 30 min and thereafter an injection of the angiotensin II, AT(1) -receptor antagonist losartan (10 mg kg(-1) ) i.v. Systemic and regional (renal and femoral) circulation was monitored in parallel to real-time spectral analysis of the arterial blood pressure signal.Results: Isoflurane anaesthesia reduced both magnitude and duration of the hypertensive response to angiotensin II infusion. The power spectral density in the frequency band that represents sympathetic activation, correlated to the changes in mean arterial pressure in conscious animals, but not during isoflurane anaesthesia.Conclusion: We conclude that the cerebrally mediated component of the hypertensive effect of circulating angiotensin II is largely eliminated by isoflurane anaesthesia. Spectral power analysis of the blood pressure signal indicates that the cerebral angiotensin II effect involves activation of sympathetic nervous activity.