Animal experiment:

Rats[1]SpragueDawley rat are used. Saline is used as control for the anpiotensin I1 type 1 receptor antagonists. ZD 7155 is given intravenously in a bolus dose of 1.082 pmol/kg, and losartan in the doses 2.165 and 6.495 pmol/kg[1].

ZD 7155 hydrochloride is an angiotensin II receptor type 1 (AT1 receptor) antagonist.

In conscious SD rats, ZD 7155 and losartan behave as competitive antagonists and the pressor response curve to angiotensin II is shifted to the right. Experiments in conscious SD rats also show that ZD 7155 is approximately ten times as potent as losartan in suppressing the angiotensin II-induced pressor response (240 ng/kg; 10 min infusion). In addition, experiments with conscious rats demonstrate that ZD 7155 could suppress the angiotensin II-induced pressor response for approximately 24 h when ZD 7155 is administered intravenously in a 1.082 μmol/kg bolus dose and angiotensin II is given at 240 ng/kg (in a 10-min infusion). Experiments in conscious SHRs using ZD 7155 (1.082 mumol/kg) and losartan (6.495 mumol/kg) as intravenous boluses indicate that both ZD 7155 and the reference compound losartan exhibit a significant antihypertensive effect[1].

References:
[1]. Junggren IL, et al. Comparative cardiovascular effects of the angiotensin II type 1 receptor antagonists ZD 7155 and losartan in the rat. J Pharm Pharmacol. 1996 Aug;48(8):829-33.