Struyker-Boudier H A, van Essen H, Smits J F
Eur J Pharmacol. 1983 Nov 25;95(3-4):151-9. doi: 10.1016/0014-2999(83)90629-5.
The hemodynamic effects of the vasodilators hydralazine, dihydralazine and endralazine were studied in conscious, unrestrained spontaneously hypertensive rats (SHR) equipped for chronic hemodynamic measurements. The arteriolar vasodilators hydralazine (0.3 mg/kg i.a.) and dihydralazine (0.3 mg/kg i.a.) caused a rapid fall in blood pressure and peripheral resistance, lasting up to 24 h in the case of dihydralazine. Immediately after injection, the cardiac output and heart rate were increased significantly. These effects only lasted for 1-2 h. The hemodynamic pattern of the new vasodilator endralazine (0.1-1 mg/kg i.a.) was very similar, with a duration of action similar to that of dihydralazine. The role of baroreceptor reflexes in the early hemodynamic effects of vasodilators was studied by comparing the effects of 0.3 mg/kg hydralazine in baroreflex-denervated and non-denervated SHR. The decrease in blood pressure and peripheral resistance was significantly larger in the denervated SHR, whereas increases in cardiac output and heart rate were almost completely absent in these animals. These data suggest that baroreceptor reflexes oppose the early fall in blood pressure and peripheral resistance induced by vasodilators. However, the activity of the baroreflex seems of very short duration, suggesting a rapid adaptation to the prevailing blood pressure. Moreover, the data show that endralazine is an effective arteriolar vasodilator in conscious SHR.
在为慢性血流动力学测量配备装置的清醒、未束缚的自发性高血压大鼠（SHR）中，研究了血管扩张剂肼屈嗪、双肼屈嗪和恩屈嗪的血流动力学效应。小动脉血管扩张剂肼屈嗪（腹腔注射0.3mg/kg）和双肼屈嗪（腹腔注射0.3mg/kg）可使血压和外周阻力迅速下降，双肼屈嗪的这种作用可持续长达24小时。注射后即刻，心输出量和心率显著增加。这些效应仅持续1 - 2小时。新型血管扩张剂恩屈嗪（腹腔注射0.1 - 1mg/kg）的血流动力学模式非常相似，作用持续时间与双肼屈嗪相似。通过比较0.3mg/kg肼屈嗪对压力感受器去神经和未去神经的SHR的作用，研究了压力感受器反射在血管扩张剂早期血流动力学效应中的作用。在去神经的SHR中，血压和外周阻力的下降明显更大，而这些动物的心输出量和心率几乎完全没有增加。这些数据表明，压力感受器反射对抗血管扩张剂引起的血压和外周阻力早期下降。然而，压力感受器反射的活动似乎持续时间非常短，表明对当前血压有快速适应。此外，数据表明恩屈嗪在清醒的SHR中是一种有效的小动脉血管扩张剂。
