Foulkes R, Gardiner S M, Bennett T
Department of Physiology and Pharmacology, Queen's Medical Centre, Nottingham, UK.
J Hypertens. 1988 Apr;6(4):305-10.
The cardiovascular responses to selective alpha 1- and alpha 2-adrenoceptor antagonism (with prazosin and idazoxan, respectively) were assessed in rats 4 weeks after unilateral nephro-adrenalectomy, contralateral adrenal enucleation and the provision of a 1% NaCl solution as drinking fluid (AEN rats) and in sham-operated (SON) rats. Measurements were made between 0700 and 1000 h and between 1400 and 1700 h, since we have previously shown that resting blood pressures (BPs) in AEN rats are higher in the morning than in the afternoon. Following prazosin administration (morning or afternoon), BP fell to similar levels in both SON and AEN rats. Idazoxan, given 20 min after the start of prazosin infusion, caused similar transient falls in BP in all four groups of rats. Following the subsequent additional antagonism of angiotensin II (Ang II) production (with captopril) and vasopressin (V1) receptors [with d(CH2)5DAVP], BP in AEN rats studied in the morning was higher than in SON rats at that time of day, and higher than in AEN rats studied in the afternoon. These findings suggest than an additional underlying mechanism capable of increasing BP exists in AEN rats studied in the morning.
在单侧肾肾上腺切除术、对侧肾上腺摘除并给予1%氯化钠溶液作为饮用水4周后的大鼠（AEN大鼠）和假手术（SON）大鼠中，评估了对选择性α1和α2肾上腺素能受体拮抗作用（分别使用哌唑嗪和咪唑克生）的心血管反应。测量在上午7点至10点以及下午2点至5点之间进行，因为我们之前已经表明，AEN大鼠的静息血压在早晨高于下午。给予哌唑嗪后（上午或下午），SON大鼠和AEN大鼠的血压均降至相似水平。在开始输注哌唑嗪20分钟后给予咪唑克生，在所有四组大鼠中均引起相似的血压短暂下降。在随后进一步拮抗血管紧张素II（Ang II）生成（使用卡托普利）和血管加压素（V1）受体[使用d(CH2)5DAVP]后，上午研究的AEN大鼠的血压在该时间段高于SON大鼠，且高于下午研究的AEN大鼠。这些发现表明，上午研究的AEN大鼠中存在一种能够升高血压的额外潜在机制。
