Interaction between β blockers and epinephrine on hemodynamics of spontaneously hypertensive rats

本文研究了非选择性β受体阻滞剂与肾上腺素的相互作用对自发性高血压大鼠和京都大鼠血流动力学的影响。(研究一)：清醒的自发性高血压大鼠和京都大鼠分别给予非选择性β阻滞剂吲哚洛尔和含1：8万肾上腺素的2%利多卡因。肾上腺素在吲哚洛尔预处理后并未引起WKY明显的血流动力学改变。另一方面，自发性高血压大鼠血压显著升高。在另一项研究中，对SHR和WKY进行了腹膜内注射去甲肾上腺素。SHR组较WKY组血压升高更明显。这一结果表明自发性高血压大鼠对刺激物比WKY更敏感。(研究2)：在非选择性β阻滞剂异丙酚全麻下，静脉注射洛拉洛尔。SHR和WKY连续静脉注射肾上腺素。通过股动脉无创测量血压和心率。我们发现，在SHR和WKY中，肾上腺素联合心得安均可显著升高血压。这些观察表明，肾上腺素对周围血管床的作用在心得安的存在下被夸大了。就病理特征而言，SHR更容易被异丙酚扩张血管。这可能是SHR和WKY血压无差异的原因。

We investigated the effects of the interaction between nonselective β adrenergic blocking agents and epinephrine on the hemodynamics in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY).(Study 1) : Nonselective β blocker, pindolol, and 2% lidocaine containing 1:80,000 epinephrine were administered to conscious SHR and WKY intraperitoneally Blood pressures and heart rate were measured by the photoplethysmografic tail cuff method. Epinephrine did not cause significant hemodynamic changes in WKY after the pindolol pretreatment. On the other hand, blood pressure increased significantly in SHR. From these observation, it was suggest that a effects of epinephrine on peripheral vascular bed was exaggerated in the presence of pindolol.In an additional study, fenylephrine was administered to SHR and WKY intraperitoneally. There was more marked increase in blood pressure in SHR than WKY. This result showed that SHR was more sensitive to a stimulator than WKY.(Study 2) : Under general anesthesia with propofol, nonselective β blocker, ploplanolol was injected intravenous. Then epinephrine was injected intravenous continuously to SHR and WKY. Blood pressure and heart rate were measured invasively through the femoral artery. We found that in both SHR and WKY, epinephrine in combination with proplanolol induced remarkable increase in blood pressure. From these observation, it was suggest that a effects of epinephrine on peripheral vascular bed was exaggerated in the presence of proplanolol. For the pathologic features, SHR is more prone to vasodilation by propofol. This might be the reason why there were no differences in bloodpressure between SHR and WKY.