Datar S, Laverty W H, McNeill J R
Can J Physiol Pharmacol. 1986 Mar;64(3):284-9. doi: 10.1139/y86-045.
Pressor responses and heart rate responses to intravenous injections (3.5-50.0 pmol/kg) of arginine vasopressin (AVP) were recorded in saline- and clonidine-treated spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Clonidine (20 micrograms/kg, i.v.) caused a marked fall of arterial pressure in SHR but not in WKY rats so that, 20 min after the injection of the alpha 2-adrenoceptor agonist, arterial pressure was similar in the two strains of rats. The curve expressing the relationship between the dose of AVP and the increase of arterial pressure for saline-treated SHR was positioned to the left of that for saline-treated WKY rats. This enhanced pressor responsiveness of SHR to AVP may have been related to impaired reflex activity since heart rate fell much less in SHR than in WKY rats for a given elevation in pressure. Pressure responses to AVP were augmented by clonidine in both SHR and WKY rats so that, similar to saline-treated rats, pressor responsiveness to the peptide was still greater in SHR. Heart rate responses to AVP were not altered significantly by clonidine. The results indicate that clonidine fails to enhance reflex activity and reduce pressor responsiveness of SHR to AVP. The increased pressor responsiveness of both SHR and WKY rats to AVP following clonidine was an unexpected finding and may be related to a peripheral interaction between alpha-adrenergic agonists and AVP.
在生理盐水处理和可乐定处理的自发性高血压大鼠（SHR）以及正常血压的Wistar-Kyoto（WKY）大鼠中，记录了静脉注射（3.5 - 50.0 pmol/kg）精氨酸加压素（AVP）后的升压反应和心率反应。可乐定（20微克/千克，静脉注射）使SHR的动脉压显著下降，但对WKY大鼠无此作用，因此在注射α2 - 肾上腺素能受体激动剂20分钟后，两种品系大鼠的动脉压相似。表达生理盐水处理的SHR中AVP剂量与动脉压升高之间关系的曲线位于生理盐水处理的WKY大鼠的曲线左侧。SHR对AVP的这种增强的升压反应性可能与反射活动受损有关，因为在给定的压力升高情况下，SHR的心率下降幅度远小于WKY大鼠。可乐定使SHR和WKY大鼠对AVP的压力反应均增强，因此与生理盐水处理的大鼠类似，SHR对该肽的升压反应性仍然更高。可乐定对AVP的心率反应无显著改变。结果表明，可乐定未能增强反射活动，也未能降低SHR对AVP的升压反应性。可乐定处理后SHR和WKY大鼠对AVP的升压反应性增加是一个意外发现，可能与α - 肾上腺素能激动剂和AVP之间的外周相互作用有关。
