Sasso E H, O'Connor D T
Eur J Clin Pharmacol. 1982;22(1):7-14. doi: 10.1007/BF00606418.
Prazosin is a post synaptic alpha adrenergic blocker effective in hypertension, whose hypotensive effect is unaccompanied by reflex tachycardia or hyperreninemia, nor by other evidence of increased sympathetic activity. We studied the baroreceptor reflex arc as a potential mediator of these effects. Twenty-two essential hypertensive men were treated with prazosin alone versus placebo, and experienced a blood pressure fall (from 114.8 +/- 3.6 down to 101.1 +/- 2.5 mmHg, p less than 0.005) unaccompanied by any change in heart rate, plasma renin activity, or several other indices of sympathetic nervous system activity (plasma dopamine-beta-hydroxylase activity; urinary excretion of free catecholamines and vanillyl mandelic acid; all p less than 0.1). Concomitant with the blood pressure fall, there was a significant depression of baroreflex arc sensitivity, from 11.4 +/- 2.0 ms/mmHg down to 6.6 +/- 1.9 ms/mmHg (p less than 0.05), without an associated change in cardiac vagal inhibition (291.2 +/- 46.2 versus 300.3 +/- 19.2 ms, p greater than 0.1). Baroreflex arc sensitivity depression may in part explain the lack of reflex sympathetic outflow noted during prazosin treatment of hypertension.
哌唑嗪是一种对高血压有效的突触后α肾上腺素能阻滞剂，其降压作用不伴有反射性心动过速或高肾素血症，也没有其他交感神经活动增强的证据。我们研究了压力感受器反射弧作为这些效应的潜在介导因素。22名原发性高血压男性患者分别接受哌唑嗪单药治疗和安慰剂治疗，血压下降（从114.8±3.6降至101.1±2.5 mmHg，p<0.005），而心率、血浆肾素活性或交感神经系统活动的其他几个指标（血浆多巴胺-β-羟化酶活性；游离儿茶酚胺和香草扁桃酸的尿排泄量；所有p<0.1）均无变化。与血压下降同时，压力反射弧敏感性显著降低，从11.4±2.0 ms/mmHg降至6.6±1.9 ms/mmHg（p<0.05），而心脏迷走神经抑制无相关变化（291.2±46.2对300.3±19.2 ms，p>0.1）。压力反射弧敏感性降低可能部分解释了哌唑嗪治疗高血压期间未观察到反射性交感神经流出的现象。
