Action and metabolism of des(Arg)kinins in mesenteric arteries

Kallidin and bradykinin can be hydrolyzed at their C-termini to produce des(Arg10)kallidin and des(Arg9)bradykinin respectively. These des(Arg)kinins, previously thought to be biologically inactive, are now known to have potent effects on B1 receptors. Although stimulation of B1 receptors has been reported to produce peripheral vasodepressor responses in certain experimental states, only constriction has been reported in isolated vessels (i.e., rabbit aorta, basilar artery, mesenteric vein). In the present study, we have investigated the biologic activity of des(Arg) kinins on a peripheral resistance vessel (rabbit mesenteric artery). We found that des(Arg)bradykinin relaxes mesenteric arteries, and that its potency relative to kallidin and bradykinin is consistent with the presence of B1 receptors. Further, intact mesenteric arteries, and a plasma membrane fraction purified from these arteries, contained a carboxypeptidase activity which was capable of producing des(Arg)kinins from both kallidin and bradykinin. Thus, these data demonstrate that the vasculature has the enzymatic capacity to form B1 kinins, and that stimulation of B1 receptors in resistance vessels can be associated with peripheral vasodilation.