Metz S A, Halter J B, Porte D, Robertson R P
J Clin Endocrinol Metab. 1978 Jan;46(1):83-90. doi: 10.1210/jcem-46-1-83.
Administration of the anti-hypertensive agent clonidine as a single (0.5 mg) oral dose or as multiple doses (0.2-0.4 mg/day for 4 days) markedly reduced plasma catecholamines (decrement = 81 +/- 3% and 68 +/- 5%, respectively; X +/- SE, % of basal; both P less than 0.001) in normal male volunteers. Five patients with various metabolic disorders showed similar responses. The absolute decrements in plasma catecholamines correlated significantly with basal catecholamine levels (P less than 0.001). Clonidine-induced decrements in mean arterial blood pressure correlated significantly with decrements in plasma catecholamines (P less than 0.001). The clonidine effect upon catecholamine levels was reversed by phentolamine (clonidine = -68 +/- 5%; clonidine with phentolamine = -1 +/- 16%). The decrements in catecholamines induced by clonidine in normal subjects were associated with increased sensitivity to the pressor effect of infusion of exogenous norepinephrine. In an analogous fashion flushing associated with endogenous adrenergic discharge was blocked by clonidine, whereas that due to exogenous catecholamines was intensified. These data are compatible with data in experimental animals suggesting that clonidine acts at least in part by interaction with a central alpha adrenergic receptor.
给予抗高血压药物可乐定单次口服剂量（0.5毫克）或多次剂量（0.2 - 0.4毫克/天，共4天），可使正常男性志愿者的血浆儿茶酚胺显著降低（分别下降81±3%和68±5%；X±SE，占基础值的百分比；P均小于0.001）。5例患有各种代谢紊乱的患者也表现出类似反应。血浆儿茶酚胺的绝对下降量与基础儿茶酚胺水平显著相关（P小于0.001）。可乐定引起的平均动脉血压下降与血浆儿茶酚胺下降显著相关（P小于0.001）。酚妥拉明可逆转可乐定对儿茶酚胺水平的作用（可乐定=-68±5%；可乐定加酚妥拉明=-1±16%）。可乐定在正常受试者中引起的儿茶酚胺下降与对外源性去甲肾上腺素输注升压作用的敏感性增加有关。类似地，可乐定可阻断与内源性肾上腺素能释放相关的潮红，而对由外源性儿茶酚胺引起的潮红则有增强作用。这些数据与实验动物的数据一致，提示可乐定至少部分通过与中枢α肾上腺素能受体相互作用发挥作用。
