Butler D G, Butt D A
Department of Zoology, University of Toronto, Ramsay Wright Zoological Laboratories, Ontario, Canada.
Arch Int Pharmacodyn Ther. 1995 Mar-Apr;329(2):272-82.
Pressor responses to [Ile5]-Angiotensin II and [Val5]-Angiotensin II were measured following single intravenous doses of 0.0075, 0.075, 0.375, 0.75 and 7.5 micrograms/kg b.w. in anesthetised rats. [Val5]-Angiotensin II was significantly (10 per cent) more potent than [Ile5]-angiotensin II when log dose was plotted against the increase in carotid arterial pressure. Doses of 0.075 microgram/kg b.w. or more of each of the two peptides gave a full pressor response within 30 seconds. However, only at the highest and, probably, nonphysiological dose of [Ile5]-Angiotensin II (7.5 micrograms/kg b.w.) was there a significant increase in noradrenaline and adrenaline concentrations measured using a radioenzymatic assay. [Val5]-Angiotensin II was more potent than [Ile5]-Angiotensin II insofar as plasma noradrenaline increased significantly (p < 0.05) following doses of 0.75 and 7.5 micrograms/kg b.w.; adrenaline at the higher dose only. Plasma dopamine was unresponsive to both peptides.
在麻醉大鼠中，静脉注射单剂量0.0075、0.075、0.375、0.75和7.5微克/千克体重的[异亮氨酸5]-血管紧张素II和[缬氨酸5]-血管紧张素II后，测量其升压反应。当以对数剂量对颈动脉血压升高作图时，[缬氨酸5]-血管紧张素II的效力比[异亮氨酸5]-血管紧张素II显著高10%。两种肽的剂量为0.075微克/千克体重或更高时，在30秒内产生完全升压反应。然而，仅在最高且可能是非生理性剂量的[异亮氨酸5]-血管紧张素II（7.5微克/千克体重）时，使用放射酶法测定的去甲肾上腺素和肾上腺素浓度才有显著增加。[缬氨酸5]-血管紧张素II比[异亮氨酸5]-血管紧张素II更有效，因为在剂量为0.75和7.5微克/千克体重后，血浆去甲肾上腺素显著增加（p<0.05）；仅在较高剂量时肾上腺素增加。血浆多巴胺对两种肽均无反应。
