Lammintausta R, Koulu M, Allonen H
Int J Clin Pharmacol Biopharm. 1979 Jun;17(6):240-43.
The effect of labetalol, an alpha- and beta-adrenergic receptor blocking antihypertensive, on plasma renin activity (PRA) and the hemodynamics of healthy volunteers at rest and during an ergometric exercise test was studied. Oral doses of 200 and 400 mg labetalol were tested against a placebo in a crossover manner. The labetalol plasma concentrations were determined. Systolic and diastolic blood pressures in the supine position decreased after 400 mg labetalol as did the response of the heart rate to exercise. The lower dose decreased the resting heart rate, but had no effect on the heart rate during exercise. The ergometric exercise induced an increase in PRA which was partly inhibited after 200 mg labetalol in a manner similar to that induced by beta-blockers in our earlier studies. After 400 mg labetalol PRA was already increased at one hour at sitting rest and this higher basal level was maintained for four hours. After this higher dose of labetalol the reaction of PRA to exercise was not significantly inhibited. In renin release the vasodilating alpha-blockade thus dominated the beta-blocking property of labetalol at the dose which decreased the blood pressure.
研究了α、β肾上腺素能受体阻断降压药拉贝洛尔对健康志愿者静息及运动试验时血浆肾素活性（PRA）和血流动力学的影响。以交叉方式对口服200毫克和400毫克拉贝洛尔与安慰剂进行了测试。测定了拉贝洛尔的血浆浓度。400毫克拉贝洛尔后仰卧位收缩压和舒张压下降，心率对运动的反应也下降。较低剂量降低了静息心率，但对运动时的心率无影响。运动试验导致PRA升高，200毫克拉贝洛尔后PRA升高受到部分抑制，其方式与我们早期研究中β受体阻滞剂诱导的方式相似。400毫克拉贝洛尔后，静息坐位1小时时PRA已经升高，且这种较高的基础水平维持了4小时。给予较高剂量的拉贝洛尔后，PRA对运动的反应未受到显著抑制。在肾素释放方面，在降低血压的剂量下，拉贝洛尔的血管舒张α阻断作用在其β阻断特性中占主导地位。
