Abstract

The production of endothelium-derived relaxing factor(s) in response to kinins was investigated in cultured porcine aortic endothelial cells. The production was estimated by the measurement of the accumulation of cyclic GMP, a response which can be attributed to activation of the soluble guanylate cyclase of the endothelial cells by endothelium-derived relaxing factor(s). Bradykinin increased markedly the levels of cyclic GMP in endothelial cells without affecting those of cyclic AMP. The bradykinin-stimulated production of cyclic GMP was transient and concentration-dependent. Kallidin (an agonist at B2-kinin receptors) but not des-Arg9 bradykinin and des-Arg10 kallidin (agonists at B1 kinin receptors) also increased, in a concentration-dependent manner, the content of cyclic GMP. The B2 kinin receptor antagonist, D-Arg0 [Hyp3, D-Phe7]bradykinin but not the B1 kinin receptor antagonists Leu8-des-Arg9 bradykinin and Leu9-des-Arg10 kallidin inhibited the production of cyclic GMP upon stimulation of the endothelial cells with either bradykinin or kallidin. Both the basal and kinin (bradykinin and kallidin)-stimulated productions of cyclic GMP were reduced by hemoglobin and potentiated by superoxide dismutase. Methylene blue also reduced kinin-stimulated production of cyclic GMP. These findings suggest that cultured porcine aortic endothelial cells possess B2 kinin receptors which are associated with the production and/or release of endothelium-derived relaxing factor(s). The endothelium-derived relaxing factor(s) produced in turn enhances the activity of soluble guanylate cyclase and induces the accumulation of cyclic GMP.