Toal C B, Leenen F H
Can J Physiol Pharmacol. 1985 Oct;63(10):1258-62. doi: 10.1139/y85-208.
Blood pressure responsiveness to iv noradrenaline and angiotensin II was studied in conscious, freely moving, age-matched spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats from 4 to 16 weeks of age. At 4 and 6 weeks the SHR showed small, but nonsignificant increases in responsiveness compared with WKY to both noradrenaline and angiotensin II. At 8 weeks they exhibited similar responses to the WKY. Subsequently, at 12 and 16 weeks decreased responsiveness to noradrenaline (nonsignificant) and angiotensin II (p less than 0.05 at 12 and 16 weeks) was observed in SHR versus WKY. At 16 weeks of age, hexamethonium caused potentiation of the blood pressure response to noradrenaline and angiotensin II, but to the same degree in the two strains. Captopril at this age did not elicit potentiation to noradrenaline or angiotensin II in either strain. These results indicate that there is no rise in blood pressure responsiveness to circulating pressor agents, parallel to the development of hypertension in SHR. Increased receptor occupancy or more active attenuating reflexes in SHR versus WKY appear not to be involved in the absence of hyperresponsiveness in intact conscious SHR at 16 weeks of age.
在4至16周龄的清醒、自由活动、年龄匹配的自发性高血压（SHR）大鼠和Wistar-Kyoto（WKY）大鼠中，研究了静脉注射去甲肾上腺素和血管紧张素II后的血压反应性。在4周和6周时，与WKY相比，SHR对去甲肾上腺素和血管紧张素II的反应性虽有小幅但不显著的增加。在8周时，它们与WKY表现出相似的反应。随后，在12周和16周时，观察到SHR与WKY相比，对去甲肾上腺素（不显著）和血管紧张素II的反应性降低（12周和16周时p<0.05）。在16周龄时，六甲铵可增强对去甲肾上腺素和血管紧张素II的血压反应，但在两种品系中增强程度相同。在这个年龄，卡托普利在两种品系中均未引起对去甲肾上腺素或血管紧张素II的增强作用。这些结果表明，与SHR高血压的发展并行，对循环升压剂的血压反应性并未升高。在16周龄的完整清醒SHR中，与WKY相比，受体占有率增加或衰减反射更活跃似乎与无高反应性无关。
