Effects of angiotensin-converting enzyme inhibitors on the vascular response to norepinephrine

The effects of three types of angiotensin-converting enzyme inhibitor, SQ 14225 (captopril), SQ 20881 (teprotide) and SA 446 (Santen, Osaka, Japan), on the vascular contraction induced by norepinephrine were studied in the perfused rat mesenteric vascular bed. (1) SQ 14225 attenuated in the vascular contraction induced by norepinephrine, but SQ 20881 and SA 446 revealed no effect on vascular reactivity. (2) The effect of SQ 14225 was not altered in the presence of bradykinin or angiotensin II in the perfusate. On the basis of these results it is suggested that the attenuating effect on the vascular response to norepinephrine may be limited to SQ 14225 and that its effect is not mediated through the renin-angiotensin or kallikrein-kinin system.