Nonaka A, Kashimoto S, Nakamura T, Kumazawa T
Department of Anesthesiology, Yamanashi Medical University, Japan.
Eur J Anaesthesiol. 1994 May;11(3):213-9.
The influence of several intravenous anaesthetics on the heart was assessed using the isolated rat heart-lung preparation. Each group received 10(-3)mol litre-1 and 10(-4)mol liter-1 of ketamine, 6 micrograms ml-1 and 60 micrograms ml-1 of midazolam, 6 micrograms ml-1 and 60 micrograms ml-1 of diazepam or 0.6 micrograms ml-1 and 6 micrograms ml-1 of flunitrazepam. Systolic blood pressure in rats receiving high doses of midazolam, diazepam and ketamine were higher than that in the control group. Heart rate in rats receiving high doses of ketamine and diazepam were lower than that in the control group. However, there were no significant changes in cardiac output among the groups. Maximum rate of left ventricular tension development in rats receiving high doses of midazolam and diazepam increased significantly in comparison with that in the control group. There were no significant changes in myocardial high energy phosphates among the groups. None of the intravenous anaesthetics, even in doses which were 100 times greater than therapeutic doses, showed any depressant effects in this preparation. Moreover, it is surprising that midazolam and diazepam produced direct increases in myocardial contractility. These results suggest that the cardiodepressant effects of intravenous anaesthetics may be due to their effects on the central nervous system.
采用离体大鼠心肺制备模型评估了几种静脉麻醉药对心脏的影响。每组分别给予10⁻³mol/L和10⁻⁴mol/L的氯胺酮、6μg/ml和60μg/ml的咪达唑仑、6μg/ml和60μg/ml的地西泮或0.6μg/ml和6μg/ml的氟硝西泮。接受高剂量咪达唑仑、地西泮和氯胺酮的大鼠收缩压高于对照组。接受高剂量氯胺酮和地西泮的大鼠心率低于对照组。然而，各组间心输出量无显著变化。与对照组相比，接受高剂量咪达唑仑和地西泮的大鼠左心室张力最大发展速率显著增加。各组间心肌高能磷酸盐无显著变化。即使剂量比治疗剂量大100倍，这些静脉麻醉药在该制备模型中均未显示出任何抑制作用。此外，令人惊讶的是，咪达唑仑和地西泮可直接增强心肌收缩力。这些结果表明，静脉麻醉药的心脏抑制作用可能归因于它们对中枢神经系统的影响。
