Effects on Smooth Muscle and Blood Vessels of Polypeptides Related to Bradykinin and to Kallidin

Abstract

Summary Ten synthetic peptides, structurally related to bradykinin or to kallidin, were compared with bradykinin for (a) stimulant activity on the excised rat's uterus, (b) i.v. vasodepressor activity in the anesthetized rat, (c) increased capillary permeability effects in rabbit's skin, and (d) coronary dilator activity in the excised cat's heart. The decreasing order of activity of these peptides was as follows: (1) bradykinin and 6-glycine bradykinin, (2) 7-glycine kallidin, (3) 7-glycine bradykinin, (4) 9-citrulline bradykinin; 1-citrulline bradykinin; bisnitrobradykinin, (5) arginylheptaglycylarginine; 1,9-biscitrulline bradykinin; fully protected bradykinin; and retrobradykinin. None of the bradykinin analogues manifested anti-bradykinin activity on the excised rat's uterus or in rabbit's skin.