Influence of inhibition of angiotensin I converting enzyme with SQ-14225 on the arterial blood pressure of mongrel dogs.

Effects of SQ-14225 (0.1, 0.3, and 3.0 mg/kg, i.v.) on the pressor responses to angiotensin I (A-I) and on the arterial blood pressure were investigated in anesthetized mongrel dogs. All the three doses significantly inhibited A-I induced pressor response (70-80%), however reduction in the blood pressure was noted only with the highest dose used. Neither bilateral nephrectomy, autonomic ganglionic blockade nor pretreatment with saralasin, an angiotensin II antagonist, altered the hypotensive activity of SQ-14225 (3 mg/kg, i.v.). The results of this study indicate that significant inhibition of angiotensin converting enzyme does not result in a decrease in the blood pressure in dogs, and that the hypotension produced by SQ-14225 may involve a mechanism yet to be identified.