ZD 7155 hydrochloride is an angiotensin II receptor type 1 (AT1 receptor) antagonist. IC50 & Target: Target: AT1 receptor^[1] In Vivo: 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].